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The hair follicle and nail unit develop and regenerate through epithelial-mesenchymal interactions. Here, we review some of the key signals and molecular interactions that regulate mammalian hair follicle and nail formation during embryonic development and how these interactions are reutilized to promote their regeneration during adult homeostasis and in response to skin wounding. Finally, we highlight the role of some of these signals in mediating human hair follicle and nail conditions., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Ingrowing toenails are a common and painful condition often requiring surgical management. Practitioners who perform surgery on ingrowing toenails include orthopaedic surgeons, general practitioners, podiatrists and podiatric surgeons. There has been limited investigation into the specific surgical approaches used by Australian podiatric surgeons for ingrowing toenails, or the associated infection rates for these procedures. The aim of this study was to assess the frequency and type of ingrowing toenail surgery performed by podiatric surgeons, and identify risk factors for post-operative infection., Methods: Data was entered into the Australian College Podiatric Surgeons (ACPS) National Audit Tool for all patients who underwent foot and ankle surgery performed by podiatric surgeons in Australia between January 2014 and December 2017. Infection within the first 30 days following surgery was recorded according to the ACPS national audit descriptors. Infection rates, risk ratios (RR) and 95% Confidence Intervals (CI) were calculated to determine postoperative infection risk., Results: Of 7682 records, 1831 reported 2712 diagnoses of ingrowing nails. Patients with a diagnosis of ingrowing toenails were younger, less likely to have systemic disease, and a lower proportion were female compared to those without ingrowing toenails. Furthermore, they were more likely to be diagnosed with a post-operative infection than those without ingrowing toenails (RR = 2.72; CI = 2.00-3.69; P < 0.01). Univariate risk factors for post-operative infection following ingrowing toenail surgery include age greater than 60 years (RR = 3.16; CI = 1.53-6.51; P < 0.01), surgery performed in an office setting (RR = 1.77; CI = 1.05-2.98; P = 0.04), and radical excision of toenail bed procedure (RR = 2.35; CI = 1.08-5.01; P = 0.04). Patients that underwent radical excision or office based procedures were on average older, and more likely to have systemic disease. Further, radical excision procedures were more likely to be performed in office base settings., Conclusions: Ingrowing toenail surgery carries a greater risk of postoperative infection than other procedures performed by podiatric surgeons. Radical excision of toenail bed was associated with higher postoperative infection rates compared to other ingrowing toenail procedures. Procedures performed in an office setting carry a higher risk of infection. Further research into these associations is recommended.

Background: Many over the counter and consumer packaged goods are promoted to enhance the appearance of hair, skin, and nails for the consumer. Nutrition is a major factor in affecting the health and appearance of hair, skin, and nails. In addition to how one eats, dietary supplementation may play a role in overall health and in the physical appearance., Aims: It was the aim of this study to objectively and subjectively evaluate the impacts of a nutritional intervention as compared to placebo on the appearances of hair, skin, and nails in healthy middle-aged adults., Methods: Randomized, double-blind placebo-controlled study with 88 subjects randomized evenly to Study Product (BiovaBio™ 450 mg/d, n = 44) or Placebo (n = 44) for 12-weeks. Outcome tests included TrichoScan HD (hair), Canfield Visia ® -CR (skin), modified FACE-Q (skin), and anchored Likert Scales (nails)., Results: Oral hydrolyzed eggshell membrane ingestion was associated with a significant improvement in facial skin appearance in crow's feet in 4 weeks and skin tone in 8 weeks, with significant impact on hair thickness, reduction in hair breakage and improvement in hair growth at 4, 8, and 12 weeks. There were no observed subjective improvements for nails (appearance, strength or growth)., Conclusions: Oral supplementation of 450 mg/d hydrolyzed eggshell membrane for 12 weeks is associated with improvement in the appearance of facial skin and hair., (© 2020 Wiley Periodicals, Inc.)

Background: Homodigital adipofascial flap is a well-established method for treating a distal fingertip defect; nonetheless, its use has some limitations. Reconstruction of fingertip injuries, with radial or ulnar tissue loss, may lead to some difficulties in providing an adequate bone coverage. The standard bipedicled technique did not allow the flap to cover the bone exposure without excessive tension. In our series, the reverse adipofascial flap had a single pedicle. The modified technique, because of its improved degree of rotation, granted the flap to reach either radial or ulnar tissue losses., Patients and Methods: We treated 15 fingertip amputations distal to the lunula (9 Allen's type II and 6 type III), the mean size of defects was 2.7 cm 2 (range, 1.8-3.2 cm 2 ), the mean age of patients was 44 years (range, 22-63 years). Quick Disabilities of the Arm, Shoulder, and Hand score and Visual Analogue Scale were evaluated along with a 2-point discrimination test; the aesthetic satisfaction of the patients was estimated subjectively using a 5-point Likert scale., Results: Mean flap size was 3.6 cm 2 (range, 2.5-4.2 cm 2 ), primary flap survival was observed in 14 out of 15 cases, partial flap necrosis was observed in 1 case, the nail grew in all fingers in about 6 months. Mean proximal and distal interphalangeal joint motion was 89° (range, 80°-100°) and 71° (range, 65°-80°), respectively. No complications were observed at the donor site. The median static 2-point discrimination was 4.5 mm (range, 3-8 mm), the mean quick DASH score was 2.6 (range, 0-9.1). All patients returned to work within a mean of 4.4 weeks (range, 4-5 weeks). The follow-up was 12 months., Conclusions: Single pedicle reverse adipofascial flap is an effective technique. This modified procedure allows a wider degree of flap rotation; it represents the ultimate arrow in our bow to address some particular defect geometry., (© 2018 Wiley Periodicals, Inc.)

Pregnancy causes some physiological skin changes, such as hyperpigmentation and striae gravidarum. Thickening of scalp hair and a prolonged anagen phase are also known to occur during pregnancy. However, a limited number of studies have been conducted on the effect of pregnancy on the nails. We aimed to investigate the effect of pregnancy on the morphology of the nail plate, specifically its growth rate and thickness. Pregnant women and a control group consisting of healthy female volunteers were included in the study. The distance from the apical point of the lunula to the midpoint of the free edge of the nail plate of the the thumb was measured with digital calipers. The measurement was repeated during the control visits and recorded in millimeters per day. The thickness of the nail plate of the thumb was measured at the midpoint of the free edge of the nail plate. A dermatological examination of the fingernails was performed for both groups. A survey was also conducted to identify any changes that occurred in the nails during pregnancy. The mean growth rate of the nail plate in pregnant women was 0.1 ± 0.05 mm/day, and in the control group it was 0.09 ± 0.05 mm/day. There was no statistically significant difference between the pregnant and control groups regarding the growth rate of the nail plate (P = 0.438). The mean thickness of the nail plate in pregnant women was 0.87 ± 0.19 mm, and in the control group it was 0.75 ± 0.17 mm. There was a statistically significant difference between the groups with respect to nail plate thickness (P < 0.001). A dermatological examination of the fingernails in the two groups did not reveal any statistically significant differences with respect to the nail findings. We determined in our study that pregnancy did not affect the growth rate and the morphology of the nails but increased the thickness of the nail plates., (© 2018 The International Society of Dermatology.)

Background: Bimatoprost has known adnexal activity and was observed to increase nail growth at two clinical centers., Objectives: In this randomized, double-blinded, placebo-controlled pilot study, we examine the effect of bimatoprost (Lumigan 0.01%), applied bid to the proximal nail fold on nail growth, nail brittleness, and intraocular pressure., Methods: Bimatoprost drops were placed on the proximal nail folds of 45 subjects on one hand (medication group) and vehicle drops to the other hand (control group). Baseline and final nail growth measurements, Goldmann applanation tensions of both eyes, and photos at 30 days were performed. Nail brittleness was subjectively graded., Results: For the 38 subjects completing the study, the final mean nail growth of the hands, the net individual nail growth of the digits (excluding chipped nails), nail brittleness, and eye pressure readings were NS at P<.05. Photos revealed no increased hirsutism, but one subject with increased skin pigmentation. The drops were well tolerated without adverse effects. Nail chipping was a limitation of the study., Conclusions: Despite the negative results in this pilot study on nail growth and brittleness, further studies with higher bimatoprost concentration (0.03%) are warranted. We recommend monitoring nail growth by etching or marking the nail rather than measuring the full nail length due to our chipped nail findings., (© 2017 Wiley Periodicals, Inc.)

Background: Brittle nail syndrome is a common problem among women and refers to nails that exhibit surface roughness, raggedness, and peeling., Aim: The goal of this study was to investigate whether daily oral supplementation with collagen peptides alleviates the symptoms of brittle nails and improves nail growth rate., Methods: In this open-label, single-center trial, 25 participants took 2.5 g of specific bioactive collagen peptides (BCP, VERISOL ® ) once daily for 24 weeks followed by a 4-week off-therapy period. Nail growth rate and the frequency of cracked and/or chipped nails as well as an evaluation of symptoms and global clinical improvement score of brittle nails were assessed by a physician during treatment and 4 weeks after discontinuation., Results: Bioactive collagen peptides treatment promoted an increase of 12% nail growth rate and a decrease of 42% in the frequency of broken nails. Additionally, 64% of participants achieved a global clinical improvement in brittle nails, and 88% of participants experienced an improvement 4 weeks post-treatment. The majority of participants (80%) agreed that the use of BCP improved their nails' appearance, and were completely satisfied with the performance of the treatment., Conclusions: This study demonstrated that the daily ingestion of BCP increased nail growth and improved brittle nails in conjunction with a notable decrease in the frequency of broken nails., (© 2017 Wiley Periodicals, Inc.)

Linear nail growth rate is affected by various conditions, one of which is the level of blood flow. Our supposition was that topical minoxidil, which has vasodilatory properties, can increase the rate of nail growth. The aim of this study was to determine the impact of topical minoxidil on nail growth. A 5% topical minoxidil solution was applied twice daily to the fingernails of 32 participants. Two groups of 16 participants were randomly chosen. In one group, the applications were made to the right index and left ring fingernails, and, in the other, the left index and right ring fingernails. During each visit (weekly during the first month and every 2 weeks during the second month), the nail length of six fingernails (index, middle, and ring of both hands) was measured using a digital caliper. Beginning in the first week, the mean nail length of the treated nails was greater than that of nails in the untreated group with statistical significance. There were no systemic or cutaneous side effects. During the first month, the mean growth of the treated nails was 4.27 mm/month compared with 3.91 mm/month in the untreated nails (P = 0.003). These findings suggest that a 5% concentration of topical minoxidil can stimulate nail growth with increased growth beginning in the first week of application. The results may have important implications for the treatment of nail disorders; however, a comparable study involving participants with nail disorders is highly recommended., (© 2017 The International Society of Dermatology.)

The nail is a unique epithelial skin appendage made up of a fully keratinized nail plate. The nail can be affected in several systemic illnesses, dermatological diseases, and inherited nail disorders. Nail dystrophies can present as isolated disorders or as a part of syndromes. Substantial progress has been achieved in the management and diagnosis of nail diseases; however, not much is known about the underlying molecular controls of nail growth. The homeostasis and development of the nail appendage depend on the intricate interactions between the epidermis and underlying mesenchyme, and comprise different signaling pathways such as the WNT signaling pathway. Digit-tip regeneration in mice and humans has been a known fact for the past six decades; however, only recently the underlying biological mechanisms by which the nail organ achieves digit regeneration have been elucidated. Moreover, significant progress has been made in identifying nail stem cells and localizing stem cell niches in the nail unit. More fascinating, however, is the role they play in orchestrating the processes that lead to the regeneration of the digit. Further elucidating the role of nail stem cells and the signaling pathways driving epithelial-mesenchymal interactions in the nail unit might contribute to the development of novel therapeutic tools for amputees., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The entire body of a patient with cancer is exposed to low-dose levels of radiation (mGy) during radiation therapy. The safety and biological impact of such exposure to low-dose radiation on the human body are largely unknown. The fingernail is a highly proliferative tissue, and its growth can be monitored during radiation treatment to analyze early effects of low-dose radiation. The fingernails of 30 patients who received external beam radiotherapy (EBRT) were used in this study to investigate the change in nail growth during fractionated radiotherapy. Lead shields were applied to some fingers to create dose variance within individual patients. The absorbed dose was measured, and the relationship between the dose and change in nail growth rate was analyzed. Other factors, including serum albumin, hemoglobin level, body weight index, age, gender and chemotherapy, were also subjected to multivariate analysis. Fingernails from patients received an average of 0.96 mGy per treatment fraction. We observed a surprising decline in fingernail growth rate during radiotherapy, which was more prominent in the nonshielded fingernails with a relatively high-absorbed dose. Such growth delay could be observed as early as one week postirradiation and lasted the entire treatment course. Using fingernail growth as a novel marker for radioresponse, the current study showed that exposure to very low-dose ionizing radiation has previously unrecognized early effects on human tissue.

Background: Many factors have been noted to alter the growth rate of both finger and toe nails, some with harder evidence than others. Infectious diseases are among the ones reported as slowing the growth rate. However, on previous studies we noticed that patients living with HIV and onychomycosis could be cured without the use of antifungal therapy, only with the immunological improvement provided by the combined antiretroviral therapy, and we wanted to prove that the growth rate is also increased in this group and thus probably contributes to the cure of onychomycosis., Methods: This was an observational, descriptive, and prospective study. We marked with a scalpel the nail plate of the first finger of the non-dominant hand and the same foot, and measured the nail growth in the subsequent medical appointments with a magnifying glass and a millimetric scale., Results: Thirteen patients completed the study, and were paired with healthy controls by age and gender. After performing Mann-Whitney U test, our results showed statistical significance among both groups, showing that patients with HIV have faster nail growth rates than those in the HIV negative group., Conclusions: There is little data on HIV nail growth rate to compare our results, but what we see in the clinical practice is that this group of patients shows a faster nail growth rate, as has also been reported for longer eyelashes, and this could be an important factor in the cure rates of onychomycosis., (© 2017 The International Society of Dermatology.)

Onychomycosis remains difficult to cure by traditional methods. The aim of this study was to evaluate the efficacy of combination therapy with a fractional erbium yttrium aluminum garnet (Er:YAG) laser and 5 % amorolfine lacquer on onychomycosis. Nine patients with bilateral nails affected by distal and lateral subungual onychomycosis were included. The bilateral nails of each patient were divided into two groups. The 20 affected nails on one side of each patient as group 1 were treated with a fractional Er:YAG laser once a week and 5 % amorolfine lacquer twice weekly, while the 20 nails on the symmetrical side of each patient as group 2 were treated with amorolfine lacquer only. The laser treatment was conducted at weeks 1, 2, 3, 4, 8, and 12 in group 1. The clinical improvement, onychomycosis severity index (OSI), maximum linear clear nail growth (MLCNG), and mycological cure rate were evaluated. At week 24, 18 of 20 (90 %) nails in group 1 had achieved obvious clinical responses. The mean OSI score showed a significant decrease (5.24) and the average MLCNG was 3.1 mm in group 1. At week 24, 15 of 20 (75 %) nails achieved a negative mycological examination in group 1, compared with four of 20 (20 %) nails in group 2. The treatments were well-tolerated by most patients. This clinical study suggests that combination therapy of a fractional 2940-nm Er:YAG laser and 5 % amorolfine lacquer is an effective, safe, and convenient treatment method for onychomycosis.

Introduction: Successful treatment of onychomycosis is both a clinical and therapeutic challenge. Effective patient education and reassurance are critical. This post hoc analysis aims to provide some guidance to physicians based on initial disease severity and influencing factors., Methods: A post hoc analysis of two multicenter, randomized, double-blind, vehicle-controlled studies evaluating the efficacy and safety of efinaconazole topical solution, 10% in mild to moderate onychomycosis. Outcomes were assessed based on baseline severity (20%-29%, 30%-39%, 40%-49%, and ≥50% affected target toenail)., Results: Overall, the mean percent affected toenail following efinaconazole treatment decreased from 36.4% to 20.6% (a 43% reduction). The percent reduction in mean percent affected toenail (range, 43.6% to 59.8%) with efinaconazole was similar irrespective of baseline severity. Improvement was only seen in the very mildest patients with vehicle and not before week 36. Improvement was influenced by gender (females did better) and disease duration (long standing disease responding less well)., Conclusions: Our onychomycosis patients treated with efinaconazole might expect a 50% improvement in their disease within a year, and this will be seen as significant by many, especially those who have suffered for many years. Many will do better, but they will need to be reminded of the slow growth of the toenail.

Although surgical treatment of nail conditions can be traced back centuries to the writings of Paul Aegineta (625-690 AC), little is known about the physical laws governing nail growth. Such a poor understanding together with the increasing number of nail salons in the high street should raise legitimate concerns regarding the different procedures applied to nails. An understanding of the physics of nail growth is therefore essential to engage with human medicine and to understand the aetiology of nail conditions. In this context, a theory of nail plate adhesion, including a physical description of nail growth can be used to determine the transverse and longitudinal curvatures of the nail plate that are so important in the physical diagnosis of some nail conditions. As a result physics sheds light on: (a) why/how nails/hooves adhere strongly, yet grow smoothly; (b) why hoof/claw/nail growth rates are similar across species; (c) potential nail damage incurred by poor trimming; (d) the connection between three previously unrelated nail conditions, i.e. spoon-shaped, pincer and ingrown nails and; last but not least, (e) why ingrown nails occur preferentially in the big toes.

Purpose of Review: Nail diseases in infants and children are an uncommon cause of consultation and are often difficult to diagnose and to manage. This review will cover nail diseases that are most commonly seen in clinical practice, including congenital and hereditary disorders and inflammatory, infective, and neoplastic nail diseases. The purpose of the review is to help the reader to recognize nail disorders at an early age and to manage them appropriately., Recent Findings: Two recent large studies have reported the clinical findings of genetic disorders involving the nails, that is, pachyonychia congenita and epidermolysis bullosa. Only a few articles gave a comprehensive review of a disease, as occurred for onychomycosis, while the majority of the reports published in the recent literature involve single cases., Summary: Nail diseases in children and neonates are not easy to diagnose by nonexperts. Basic knowledge of the anatomy and biology of the nail facilitates their diagnosis as the understanding of their pathophysiology. This review gives hints at the most common nail diseases that affect infants and children.

A 7-month-old girl was evaluated for V-shaped ridging of the fingernails consistent with chevron nails. Chevron nails are a normal variant in the pediatric population that is frequently outgrown. This case nicely demonstrates this normal finding that has so rarely been reported in the literature., (© 2013 Wiley Periodicals, Inc.)

Background: Onychomycosis is a common nail infection that is difficult to treat successfully. The prevalence increases with age and is associated with diabetes. Oral treatments are limited by drug interactions and potential hepatotoxicity; topical treatments, by modest efficacy., Objective: We investigated the efficacy and safety of a solution using a novel topical triazole antifungal, efinaconazole, in distal lateral subungual onychomycosis (DLSO)., Methods: Multicenter, randomized, double-blind, vehicle-controlled phase 2 study in mild to moderate toenail DLSO (n=135). Subjects randomized (2:2:2:1 ratio) to receive efinaconazole 10% solution (with or without semiocclusion), efinaconazole 5% solution, or vehicle, once daily for 36 weeks, with one 4-week posttreatment follow-up (week 40). Efficacy assessments included complete cure, mycologic cure, clinical efficacy, and other assessments of overall treatment effectiveness. No efficacy variables were designated as primary., Results: At follow-up, complete cure was numerically higher in all active groups (16%-26%) compared with vehicle (9%). Mycologic cure rates with efinaconazole 10% semiocclusion, efinaconazole 10%, and efinaconazole 5% were 83%, 87%, and 87%, respectively. Efinaconazole 10% (with or without semiocclusion) demonstrated significantly greater clinical efficacy and treatment effectiveness when compared with vehicle (P=.0088 and .0064; .0056 and .0085, respectively, for both efinaconazole 10% groups). Adverse events were generally similar and mild. Local-site reactions were restricted to few subjects and did not differ meaningfully from those produced by vehicle., Conclusions: This study provided evidence that once-daily efinaconazole 10% solution (with or without semiocclusion) applied topically for 36 weeks was more effective than vehicle in treating DLSO and was well tolerated. Based on these results, efinaconazole 10% solution was chosen for the phase 3 development program.

Nail unit dermatopathology is a growing field filled with many challenges. Many advances in this field have been made in the last 5 years. This review article provides an update on new information and studies published in that period of time. We divided these works into different sections, including clinical and pathologic challenges in diagnosis and treatment of nail disorders, nail unit biopsy and processing techniques, normal nail unit histology, nail plate structural and growth pathology, metabolic disease, inflammatory conditions, onychomycosis, benign growths, malignant growths, and dyschromias. Specific highlights include advances in the marking and orientation of nail unit biopsies for improved histologic interpretation, improved nail plate softening techniques, new methods for histologic evaluation of onychomycosis, descriptions of newly described benign growths unique to the nail unit, and the morphologic and immunohistochemical distinction between benign and malignant pigmented lesions of the nail unit., (© 2012 Wiley Periodicals, Inc.)

Background: Severely incurved toenails are accompanied by deformity of the toenail growth plate. In such a condition, partial removal of the nail and nail bed and simple unfolding of the nail itself frequently result in the recurrence of symptoms. We sought to design and develop a new technique for the treatment of incurved toenail with growth plate deformity and to report the results of treating this disease entity., Methods: Forty consecutive patients (52 cases) underwent treatment of symptomatic incurved toenails with a new technique named matrixplasty. The mean ± SD patient age was 40.3 ± 18.9 years. Last follow-up was at a mean ± SD of 18.0 ± 1.3 months. An American Orthopedic Foot and Ankle Society (AOFAS) forefoot hallux score was assigned, and patients were evaluated before treatment and at last follow-up. Patient satisfaction and the recurrence rate of the deformity were evaluated. For evaluation of improvement in toenail shape, the center to edge angle of the toenail was measured before treatment and at last follow-up. The complication rate was also evaluated., Results: All of the ingrown toenails healed, and the nail deformities were corrected within 3 weeks after the procedure. None of the incurved toenails had recurred by last follow-up. The mean pretreatment AOFAS forefoot hallux score was 72.9, and it improved to 99.6 by last follow-up (P < .001). Every patient was very satisfied or satisfied with the results of treatment. The mean ± SD center to edge angle of the toenail improved from 53.3° ± 9.5° to 15.3° ± 5.2° by last follow-up (P < .001). Minor paronychia, which was managed with local wound dressing and oral antibiotics, was identified in four cases. No other complication was identified., Conclusions: Matrixplasty showed excellent clinical results in the treatment of severe incurved toenail, and this newly developed procedure showed improvement of the deformed toenail and its growth plate.

A rapid and simple gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the simultaneous detection and quantification of five psychotropic phenylalkylamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and norketamine) in toenails. After external decontamination, nail clippings were mechanically pulverized with a bead mill and then incubated in methanol under ultrasonication at 50°C for 1 h. The resulting solutions were evaporated to dryness, derivatized, and analyzed by GC-MS. The intra- and inter-day precisions were within 10.7% and 13.9%, respectively. The intra- and inter-day accuracies were -4.2% to 5.0% and -2.4% to 8.4%, respectively. Limits of detection and quantification for each analyte were lower than 0.024 and 0.08 ng/mg, respectively. The recoveries were in the range of 80.6-87.5%. The results indicated that the proposed method is a simple, rapid, accurate, and precise for quantification of five phenylalkylamines in nails. The method was successfully applied to the simultaneous detection and quantification of phenylalkylamines in nail samples of possible drug abusers., (© 2011 American Academy of Forensic Sciences.)

Background: Clinicians encounter pincer nails at a high incidence among bedridden cases who are free from weight bearing. The mechanical force transmitted by walking and loading may affect the nail configuration. This study was aimed at evaluating the influence of mechanical forces on the nail configuration., Methods: Study 1 was conducted on a sample size of 318 great toenails, with the subjects classified into the following 3 groups: healthy volunteers, participants who were bedridden for less than 3 months, and participants who were bedridden for more than 3 months. Study 2 was conducted in 12 subjects with unilateral loading., Assessments: The configuration of the great toenails, in terms of the curve index (defined as the nail height/nail width), was compared., Results: In study 1, the curve index increased significantly as the duration of the bedridden state became longer (17.5 ± 4.75, 28.9 ± 11.0, 36.4 ± 9.58, respectively). In study 2, the curve index on the nonloaded side was significantly higher than that on the loaded side (40.0 ± 8.63 vs. 27.0 ± 8.39)., Conclusion: Our results suggest that mechanical forces may affect the nail configuration and be involved in the pathophysiology of nail deformities., (Copyright © 2012 S. Karger AG, Basel.)

The rewarding use of nail clippings processed histologically for the diagnosis of some nail diseases is well established. A new application of the nail plate biopsies (NPBs) is the detection of crystals in the subungual horn. Besides other subungual crystals, urate crystals are heretofore undescribed. This presentation adds to the advantages of an NPB: the detection of some cases of gout on which urate crystals are extruded subclinically. While searching for fungi, 2 cases of gout were diagnosed histologically, aided by unstained thick sections. A history of gout was then confirmed. No tophi were noted in or near the nail field. Chasing for crystals opens the study of fluids that may exude or transude into nail structures, a kind of "nail window" into hematic or metabolic abnormalities. In sum, the abundance of cytologic and histologic findings in an NPB can expand the armamentarium of physicians to evaluate nail diseases and even systemic diseases in a noninvasive manner.

The anatomic and physiologic changes occurring with pregnancy result in a variety of symptoms affecting the lower extremity. The purpose of this investigation is to provide a comprehensive look at the lower extremity changes experienced during pregnancy and correlate symptoms with underlying etiology in a literature review. In this retrospective study, 100 postpartum women were interviewed regarding the lower extremity changes experienced in pregnancy. The interview included dermatologic, vascular, neurologic, and musculoskeletal portions. Results demonstrate more than 50% of women reported faster toenail growth, roughened toenail texture, increased dryness of the skin, swelling of the foot, ankle, and leg, unsteady gait, increased foot width, and hip pain. Though a majority of patients did not experience the remaining symptoms represented in the interview, all results are pertinent and deserve understanding to provide better insight and care for the pregnant woman. Therefore, a thorough literature review is presented to correlate the outcomes of the present study with previously published research., (Copyright 2010 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Distal replantation is an excellent model to study the results of nerve repair. We aim to demonstrate differences in aesthetic, sensory, and functional outcomes in fingertip replantation, with and without nerve repair. We recruited 28 fingers in 28 patients, who had successful distal replantation in 5 years. Half of the fingers had nerves repaired. Mean follow-up was 39 months. Symptoms of pain, numbness, cold intolerance, scar hypersensitivity, pulp atrophy, and weakness were reported. Nail width, pulp length, 2-point discrimination, Semmes-Weinstein test, and power were evaluated. We used chi-square tests of independence to examine association between nerve repair and symptoms, and independent T tests and Mann-Whitney U tests to analyze difference between replantation with and without nerve repair according to objective results. Chi-square tests reviewed no significant association between nerve repair and symptoms. Mann-Whitney U tests showed no significant difference between the groups, with and without nerve repair. All fingers showed mean 2-point discrimination of 5.6 mm, and Semmes-Weinstein test results of green in 3 fingers and blue in 17. There was no significant difference in overall outcomes in repairing nerve or not in distal finger replantation. Both groups had satisfactory outcomes. Possibly, spontaneous neurotization is present, and nerve repair is not necessary, which may help to shorten the operation time and decrease extensiveness of surgeries., (Thieme Medical Publishers.)

Background: Human nail clippings are increasingly used in epidemiological studies as biomarkers for assessing diet and environmental exposure to trace elements or other chemical compounds. However, little is known about the growth rate of human nails., Objective: To estimate the average growth rate of fingernails and toenails and examine factors that may influence nail growth rate., Methods: Twenty-two healthy American young adults marked their nails close to the proximal nail fold with a provided nail file following a standardized protocol, and recorded the date and the distance from the proximal nail fold to the mark. One to three months later, participants recorded the date and distance from the proximal nail fold to the mark again. Nail growth rate was calculated based on recorded distance and time between the two measurements., Results: Average fingernail growth rate was faster than that of toenails (3.47 vs. 1.62 mm/month, P < 0.01). There was no significant difference between right and left fingernail/toenail growth rates. The little fingernail grew slower than other fingernails (P < 0.01); the great toenail grew faster than other toenails (P < 0.01). Younger age, male gender, and onychophagia were associated with faster nail growth rate; however, the differences were not statistically significant., Conclusion: Nail growth rates have increased compared with previous estimates conducted decades ago. Toenail clippings may reflect a long exposure time frame given the relatively slow growth rate.

A gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the simultaneous qualification and quantification of methamphetamine (MA), amphetamine (AP), 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-amphetamine (MDA), ketamine (KET) and norketamine (NKT) in fingernails. Fingernail samples (20mg) were washed with distilled water and methanol, digested with 1.0M sodium hydroxide at 95 degrees C for 30 min, and then extracted with ethyl acetate. Extract solutions were evaporated to dryness, derivatized using heptafluorobutyric anhydride (HFBA) at 60 degrees C for 30 min, and analyzed by GC-MS. The linear ranges were 0.1-20.0 ng/mg for AP, MDMA and NKT, 0.2-20.0 ng/mg for MA and MDA, and 0.4-20.0 ng/mg for KET, with the coefficients of determination (r(2)>or=0.9989). The intra- and inter-day precisions were within 7.1% and 10.6%, respectively. The intra- and inter-day accuracies were -10.9% to 0.8% and -4.3% to 4.5%, respectively. The limits of detections (LODs) and the limits of quantifications (LOQs) for each analyte were lower than 0.094 ng/mg and 0.314 ng/mg, respectively. The recoveries were in the range of 72.3-94.9%. The average fingernail growth rates of two subjects for three years and six subjects for two months were 3.12 mm/month and 3.16 mm/month, respectively. The method proved to be suitable also for the simultaneous detection and quantification of MA, MDMA, KET and their metabolites in fingernails., (2009 Elsevier Ireland Ltd. All rights reserved.)

Background Onychomycosis is a common disease; topical treatment is usually poorly effective, while systemic treatment is more effective but may be associated with side-effects. Iontophoretic drug delivery may improve drug penetration through the nail and lead to better therapeutic results. Objectives To evaluate the efficacy, safety and tolerability of topical treatments with terbinafine HCl delivered with or without an iontophoretic patch in patients with onychomycosis of the toenails. Methods Patients enrolled into the study were divided randomly into two groups. Group A was treated with terbinafine and an iontophoretic patch (at a constant current density of 100 microA cm(-2)). Group B was treated with terbinafine without iontophoresis. Treatment was overnight wear, every day, 5 days per week, for 4 weeks. Follow-up period was 8 weeks from the end of treatment. Results A significant clinical response was recorded in patients of group A (active group). The percentage of patients having healthy toenail growth of more than 1.5 mm at the end of treatment was 40% compared with 11% in patients treated with terbinafine without current (passive group). The percentage of patients having fungal elements (KOH) in nail specimens decreased significantly at 8 weeks following the completion of treatment: 16% in the active group vs. 53% in the passive group. Patients in the active group reported a tingling sensation that is expected when using an iontophoretic drug delivery treatment. Conclusions The delivery of terbinafine under an electrical current of 100 microA cm(-2) appears to be efficacious and safe and is well tolerated for the treatment of nail onychomycosis.

Valproic acid (VPA) is frequently used as an antiepileptic drug. Several side effects are known. We report on a child with onychomadesis as a possible side-effect of treatment with VPA. Normal nail growth was observed after stopping VPA. The pathomechanism of onychomadesis due to VPA treatment remains unclear.

Nails have been suggested as suitable biomarkers of exposure to F, with the advantage of being easily obtained. The effect of water F concentration, age, gender, nail growth rate and geographical area on the F concentration in the fingernail and toenail clippings were evaluated. Volunteers (n = 300) aged 3-7, 14-20, 30-40 and 50-60 years from five Brazilian communities (A-E) participated. Drinking water and nail samples were collected and F concentration was analyzed with the electrode. A reference mark was made on each nail and growth rates were calculated. Data were analyzed by ANOVA and linear regression (alpha = 0.05). Mean water F concentrations (+/- SE, mg/l) were 0.09 +/- 0.01, 0.15 +/- 0.01, 0.66 +/- 0.01, 0.72 +/- 0.02, and 1.68 +/- 0.08 for A-E, respectively. Mean F concentrations (+/- SE, mg/kg) ranged between 1.38 +/- 0.14 (A, 50-60 years) and 10.20 +/- 2.35 (D, 50-60 years) for fingernails, and between 0.92 +/- 0.08 (A, 14-20 years) and 7.35 +/- 0.80 (E, 50-60 years) for toenails. Among the tested factors, geographical area and water F concentration exerted the most influence on finger- and toenail F concentrations. Subjects of older age groups (30-40 and 50-60 years) from D and E showed higher nail F concentrations than the others. Females presented higher nail F concentration than males. Water F concentration, age, gender and geographical area influenced the F concentration of finger- and toenails, and hence should be taken into account when using this biomarker of exposure to predict risk for dental fluorosis., (2009 S. Karger AG, Basel.)

Overall survival rate for 143 digits with complete amputation of the distal phalanx was 78%. Replanted digits that underwent venous anastomosis showed a very high survival rate of 93%. Loss of the distal interphalangeal joint function in subzone IV was significantly inferior to that in subzones II and III. Protective sensation was achieved in 96% of replanted digits. Sensory recovery in the absence of nerve repair was significantly worse for avulsion injury than for crush injury. Nail deformity tended to be increased for replanted digits in subzone III or with crush-type injury. Successful venous anastomosis appears to offer the best way to promote survival of replanted digits. If venous anastomosis is infeasible, a replanted digit can survive with any methods for venous drainage in subzones II and III, but does not survive in subzone IV. To minimise nail deformity, repair of the germinal matrix is necessary.

Homeobox genes are an evolutionarily conserved class of transcription factors that are key regulators during developmental processes such as regional specification, patterning, and differentiation. In this review, we summarize the expression pattern, loss- and/or gain-of-function mouse models, and naturally occurring mouse and human mutations of known homeobox genes required for the development of ectodermal appendages., ((c) 2008 Wiley-Liss, Inc.)

The distal region of the nail unit, which marks the transition of the nail bed to the hyponychium, is known clinically as the onychodermal band (ODB). For several authors, the ODB is described as 2 subbands of tonal values: slightly milky and pink from proximal to distal. However, its 2 subbands show individual variation and are often scarcely visible. It has been stated that the proximal subband, that is, the white band of Pinkus, corresponds histologically to the attachment of the compact orthokeratotic layer of the hyponychium to the nail plate. In 2 studies, I have individualized a transitional zone between the nail bed and the hyponychium: the nail isthmus. In these previous studies, the ODB was not visible. The purpose of this article is to analyze the anatomo-clinical correlations between the nail isthmus and the ODB and to highlight some new physiological information concerning the nail growth. A case showing clearly the 2 clinical subbands of ODB was investigated. In addition, all the longitudinal sections of the 5 normal nail unit specimens, used in the 2 previous studies, were reviewed to analyze the ventral surface of the nail plate in longitudinal planes. The nail isthmus can be described synthetically by 2 features: (1) a stair-like appearance of the epithelium of the distal nail bed with a marked depression of the epithelium below the inferior surface of the nail plate (2) a specialized mode of attachment of its horny layer to nail plate via a horizontal mode of differentiation. The white band of Pinkus corresponded histologically to the nail isthmus. Its white color was caused by alteration in light diffraction in the thin compartment of pale parakeratotic corneocytes squeezed between the nail plate and the epithelium of the nail isthmus. The pink middle band corresponded to the 2 horny layers surmounting the epidermis of the hyponychium: the compact horny layer of the hyponychium and the thin pale "tongue-like" parakeratotic extension of the nail isthmus. The variable thinness of both the suprapapillary plates of hyponychium and the 2 horny layers surmounting this area explained the variable visibility of the well-developed vascular network of the dermal papillae of hyponychium, that is, the variegation of the middle subband. The review of all step sections of the normal distal nail unit cut longitudinally showed that the ventral surface of the nail plate was slightly serrated in longitudinal planes. The nail isthmus belongs functionally to the nail bed. The strong adherence between the nail plate and the nail bed is replaced by an effective sealing between the thin pale tongue-like parakeratotic extension of the nail isthmus and the nail plate. In contrast, the hyponychium belongs functionally to fingertip and exhibits an epidermal-type horny layer, that is, the horny layer of the distal hyponychium is a supportive structure. As the ventral surface of the nail plate is undulated in its transversal and to a lesser extend in its longitudinal axis, the nail bed and the nail plate grow forward together. The nail plate is "pushed" out by 2 factors: (1) the matrix which makes a new plate, (2) the nail bed which moves slowly, parallel to the direction of the nail growth, toward the tiny grooves and ridges of the inferior border of the nail plate. According to the anatomo-clinical description of the distal nail unit, the nomenclature of this region could be simplified. The term nail isthmus should be proposed as equivalent of the white band of Pinkus. The hyponychium could be compared with the follicular infundibulum as a zone bordering the surrounding epidermis, and the term nail infundibulum could be considered to be synonymous for hyponychium and ODB.

Bajiaolian (Dysosma pleianthum), a species in the Mayapple family (Podophyllum pelatum), has been widely used as a traditional Chinese herbal medication for the remedies of snake bite, tumor growth, post-partum recovery, and acne. It has also been used in western medicine, especially topically for various skin lesions. Both oral ingestion and dermal application may result in severe toxicity. The clinical presentations reported after Bajiaolian poisoning include nausea, vomiting, diarrhea, abdominal cramps, tachycardia, orthostatic hypotension, paralytic ileus, urinary retention, hepatorenal dysfunction, leukocytosis followed by leukopenia, thrombocytopenia, prolonged areflexia, prolonged paraethesia and sensory ataxia, dizziness, fever, memory impairment, hallucinations, paranoia, convulsion, fainting, and coma. There are no previous reports in the literature about the cessation of nail growth as a clinical presentation following Bajiaolian poisoning. We present a case of nail growth that was halted for more than seven years after a single case of Bajiaolian poisoning.

This paper describes a useful way of ensuring complete surgical ablation of the germinal matrix of the nail bed by staining the proximal envelope with Bonney's Blue dye.

This study aimed to determine the lag time between increased fluoride (F) intake and F detection in human nails, as well as the influence of nails growth rate and length on this. Ten 20- to 35-year-old volunteers received 1.8 mg F daily, for 30 days. Nail growth rate and length were determined for all fingernails and toenails. Nail samples were collected at the beginning of the study and every 2 weeks (15 collections in all) and F concentrations were determined. The growth rate was statistically higher in fingernails than in toenails. No statistically significant differences were observed between right and left sides. Growth rate was significantly greater for big toenails than for the other toenails, but this pattern was not found for fingernails. The estimated mean lag times for F detection in fingernails and toenails were 101 and 123 days, respectively. An apparent increase in fingernail F concentrations was observed 84 days after the beginning of the study, although this was not statistically different from baseline. For toenails, statistically significant increases in F concentration in relation to baseline were observed 112 and 140 days after increased F ingestion. These increases occurred within the 95% confidence intervals for the calculated mean lag time for fluoride detection in nails. Considering the large amount of sample provided by the big toenails, together with their faster growth rate, as well as the fact that toenails are less prone to environmental contamination, our data suggest that big toenails are more suitable biomarkers of fluoride intake., (Copyright (c) 2006 S. Karger AG, Basel)

Transverse furrows, or Beau's lines, were noted in the fingernails of all 6 divers following a deep saturation dive to apressure equal to 1100 feet (335 meters) ofsea water (3,370 kPa), and in 2 of6 divers following a similar dive to 1000 feet (305 meters) of sea water (3,164 kPa). Both dives took place at the Ocean Simulation Facility of the Navy Experimental Diving Unit in Panama City, Florida. The divers breathed a partial pressure of 0.40 - 0.44 atm abs (40.5 - 44.6 kPa) oxygen, with the balance helium, during most of the time under pressure. All divers performed hard work on bicycle ergometers during the dives. Four of the divers on the first dive were treated during the dive for pain-only decompression sickness. Beau's lines have been reported in numerous medical conditions such as typhus, rheumatic fever, malaria, myocardial infarction, and other severe metabolic stresses. To the author's knowledge this is the first report of Beau's lines associated with saturation diving.

Fingernail clippings collected from 97 consenting females, who admitted amphetamines and/or opiates use and are currently under treatment, were quantitatively analyzed for the presence of methamphetamine and amphetamine. Sixty-two subjects were found positive for methamphetamine/amphetamine. Paired nail-hair specimens were collected from 6 of these subjects for a 12-week period and analyzed to determine the duration of detectability and deposition characteristics of amphetamines in fingernails; whether data derived from the analysis of nail clippings and hair sections are reflective of drug use patterns; and whether there is a relationship between the analytical data derived from the paired nail-hair specimens. Typical sample pre-treatment procedures and GC-MS protocols were evaluated to establish the validity of various analytical parameters and to ensure that the resulting data can be properly interpreted. Major findings include 1. Methamphetamine was found in the nails of 62 subjects collected in Week 0. The distribution of methamphetamine concentrations (ng/mg) in these nail samples are range, 0.46-61.50; mean, 9.96; and standard deviation: 13.33. The corresponding data for amphetamine are < 0.20-5.42, 0.93, and 1.01, respectively. 2. Sectional analyses of hair samples collected from 6 subjects in Week 0 show methamphetamine concentrations peak at different distances from the root. 3. The concentrations of methamphetamine and amphetamine in nail clippings are generally lower than the first 1.5-cm section of hair samples collected at the same time from the same individual. 4. Amphetamine/ methamphetamine concentration ratios in nail clippings and hair samples are comparable. 5. Methamphetamine concentration in the nail clippings collected at Weeks 0, 4, 8, and 12 decreases in a pattern similar to that exhibited by the first 1.5-cm sections of the hair samples collected at the same time.