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Background: Pityriasis lichenoides et varioliformis acuta (PLEVA) is a rare dermatosis recognized as a benign condition of unknown etiopathogenesis. It is more common in pediatric patients and young adults and is characterized by multiple small or large erythematous plaques spread over the trunk and extremities., Case Report: We describe the case of a 5-year-old male, previously healthy, with multiple erythematous lesions that disappeared leaving hypopigmented macules. The biopsy reported histological changes suggestive of mycosis fungoides. After a second revision of lamellae in this hospital, lymphocytic vasculitis (LV) with focal epidermal necrosis consistent with acute pityriasis lichenoides (PL) was identified., Conclusions: The existing knowledge about PLEVA lacks a consensus in specifying its classification, etiopathogenesis, diagnosis, and treatment, so this clinical condition represents a medical challenge. The diagnosis is made by clinical suspicion and confirmed by histology. The objective of this article was to report a case of PLEVA with an atypical presentation due to its histopathological findings, being the first report showing LV in children, as well as a review of the literature., (Copyright: © 2023 Permanyer.)

Background and objectives : Pytiriasis alba (PA) is a common skin disorder which affects 80% of children between six and 16 years. The etiology of PA is unclear, but hypo-pigmented patches in photo-exposed zones characterize the disease. Because the high ultraviolet exposition of the skin promotes an acute inflammatory response and an increase of oxidative stress (OS), this study aimed to evaluate the expression levels of inflammatory and OS-related genes in skin biopsies, and their association with PA. Materials and Methods : A cross-sectional study was carried out. Skin biopsies of the lesion sites and healthy skin (controls) from 16 children with PA were evaluated. The tissue expression of IL-4, IL-6, IL-17A, TNFα, INFγ, IL-1β, SOD1, and HMOX1 was analyzed by qRT-PCR, using SYBR Green and glyceraldehyde-3-phosphate dehydrogenase gene as the endogenous control. Results : There were differences in the ΔCq values of HMOX1, SOD1, IL-6, and IFNγ between tissue with lesions and healthy skin ( p < 0.05). Compared with healthy skin, IL-6, IFNγ, HMOX1, and SOD1 were predominantly under-expressed in the lesion sites. However, 25% of skin biopsies with lesions showed over-expression of these four genes. Positive correlations between the expression of IL-6 and HMOX1, SOD1, and IFNγ ( p < 0.05) were also observed. Conclusions : Our results suggest the presence of molecular stages of PA, defined according to the over-expression (first stage) or under-expression (second stage) of the HMOX1, SOD1, IL-6, and IFNγ genes in abnormal skin tissue. These findings may have implications for the selection of treatment for PA-related lesions.

Although pityriasis alba is a common dermatologic condition, its pathogenesis is poorly understood, and there are many discrepancies in the literature. To assess the effect of the duration of disease on the histologic findings, a search of cases labeled "pityriasis alba" was performed on any cases submitted to our dermatopathology laboratory. Of 179 cases of pityriasis alba, five cases identified the duration of the disease, when the biopsy was taken. A biopsy for a lesion of only 1-month duration demonstrated groups of large, prominent melanocytes heaped up upon one another. Compared with biopsies from patients who had the lesions for increasingly longer periods of time, it was apparent that the melanocytes became progressively less abundant and smaller with less prominent dendritic processes. The time that the biopsy is taken may affect the histologic findings of pityriasis alba. Additionally, an abundance of melanosomes was observed between the melanocytes in all sections examined which may reflect a problem with the transfer of melanosomes into keratinocytes in this condition., (Copyright © 2019. Published by Elsevier Inc.)

Background: Pityriasis rotunda is a rare skin disease characterized by the presence of multiple, round or oval, sharply demarcated hyperpigmented scaly patches. It has been described in Japan, South Africa, and in some other countries. The cause of pityriasis rotunda is usually idiopathic but may be associated with certain internal malignancy or systemic diseases., Objective: The aim of this study is to describe this rare entity in Jordan in a retrospective study during the last 10 years. Jordan, as a Middle Eastern country, had no previous reports about this rare disease. In addition, the intention was to report any systemic association with the disease. Some of the cases were examined by dermoscopy. No previous reports documented dermatoscopic features of the disease., Results: We could report 23 cases during the last 10 years. Eighteen cases were females and five males, in an age range of 9-38 years. There were three familial cases. The dermatoscopic findings were well demarcated, hyperpigmented with brownish patches with polygonal scales. These scales were more defined, not homogeneous in color, and separated from each other by paler stria., Conclusions: The cases of the study seem to indicate the rarity of the disease in Jordan. Our case fits neatly into the benign form of the disease with lack of association with any underlying diseases., (© 2018 The International Society of Dermatology.)

Pityriasis folliculorum has been described as a dry type of rosacea with extensive proliferation of Demodex folliculorum in pilosebaceous follicles of the skin. This skin condition is frequently difficult to manage, with various treatment options showing mixed efficacy. Oral ivermectin, a macrocyclic lactone parasiticide with anti-inflammatory and anti-parasitic effects, is one of the leading treatment modalities for demodicosis. Topical ivermectin has recently been FDA approved as therapy for rosacea. We present the case of a woman with pityriasis folliculorum who showed significant improvement from using topical ivermectin with no adverse events related to treatment.

We report on a 21-year-old woman with a 3-year history of crusts and erosions on her scalp that had appeared after starting treatment with adalimumab due to Crohn's disease. By clinicopathological correlation pityriasis amiantacea with underlying folliculitis decalvans was diagnosed. Topical and systemic antibiotic treatment showed rapid response. The occurrence of pityriasis amiantacea in folliculitis decalvans associated with tumor necrosis factor (TNF)-α inhibitor therapy is remarkable and highlights the ambivalent role of TNF-α in diseases with immunological dysfunctions in combination with infections.

Pityriasis alba (PA) is a skin disorder that affects children and adolescents. Although it is common worldwide, its incidence is markedly higher in darker skin phototypes. Its characteristic features include an extended, multistage course and spontaneous remissions and recurrences. Preceded by erythematous changes, patches of hypopigmented skin of up to a few centimeters in diameter appear on the upper body. Pruritus may accompany it. Even though its etiology is unknown, possible reported triggering factors include sunlight, beauty treatments, and microorganisms, among others. Calcineurin inhibitors play the most crucial role in PA pharmacotherapy. PA often coexists with atopic dermatitis and is considered one of its milder forms., (© 2015 Wiley Periodicals, Inc.)

Pityriasis rotunda disorder of keratinization clinically described as persistent, large, sharply defined circular patches of ichthyosiform scaling with no inflammatory changes. Patients with pityriasis rotunda may be classified into one of two groups, which are based on ethnicity, number of lesions, family history, and association with systemic diseases. A 45-year-old woman presented with asymptomatic, sharply-demarcated, round, scaly, hyperpigmented lesions on her leg that had been present for several years. Our patient did not have systemic disease or malignancy and so does not fit into groups already described.

Pityriasis rotunda (PR) is an uncommon chronic dermatosis, which may be idiopathic or may be associated with infections or malignancy. We describe the clinical and biochemical findings of two patients with multiple myeloma, who were incidentally diagnosed with PR, and detail the clinical conditions with which this rare paraneoplastic phenomenon may be associated. Although PR is a rare condition, it may be found as a paraneoplastic phenomenon in a range of conditions, and thus should be recognised as an important clinical sign., (© 2014 British Association of Dermatologists.)

Background: Pityriasis alba affects 1% of the world population and about 9.9% of the children in Brazil. However, its etiology remains uncertain., Objective: The objective of the present study was to evaluate the immunoexpression of factor XIIIa in dermal dendrocytes of skin lesions of pityriasis alba., Method: Twenty patients with pityriasis alba and 20 patients with atopic dermatitis underwent biopsy. The dermal dendrocytes marked by factor XIIIa were counted by means of immunohistochemical analysis., Results: The mean amount of dermal dendrocytes found in the patients with pityriasis alba was 2, whereas in the patients with atopic dermatitis it was 4, with a statistically significant difference between them. A cutoff point of 3 cells/square inch was established to differentiate pityriasis alba from atopic dermatitis, with 80% sensibility and 90% specificity., Conclusion: We believe that pityriasis alba and atopic dermatitis should be considered different clinical forms within the spectrum of atopic disease, in which sun radiation plays an important role by modulating the progression of the disease.

We present a 65-year-old man with Darier disease with pityriasis amiantacea on the scalp, alopecia, and congenital facial nerve palsy.

Acquired hypopigmentary disorders comprise a significant group of disorders that affect Indians and Asians. The pigment disturbance in darker skin individuals can be very distressing to the patient and the family. These disorders cover a wide array of pathologies including infections, autoimmune processes, lymphoproliferative disorders, and sclerosing diseases. Histological diagnosis is particularly important because treatments for these diseases are varied and specific. This review will focus on histopathological diagnosis based on clinicopathological correlation for commonly encountered disorders such as leprosy, vitiligo, lichen sclerosus, pityriasis alba (PA), and pityriasis versicolor (PV). Atypical or uncommon clinical presentation of classic diseases such as hypopigmented mycosis fungoides (HMF) and hypopigmented sarcoidosis are also included.

Despite an increasing knowledge of dandruff and seborrheic dermatitis (D/SD), the pathophysiological understanding is still incomplete but suggests a role of Malassezia yeasts in triggering inflammatory and hyper-proliferative epidermal responses. The objective of this report is to review published literature from in vivo studies of D/SD populations to provide a more complete description of overall scalp health. New biomolecular capabilities establish a depth of pathophysiological understanding not previously achievable with traditional means of investigation. Biomarkers representing inflammation, hyper-proliferation and barrier function are all perturbed by the D/SD condition and robustly respond to therapeutic resolution. These biomarkers can be sampled noninvasively, enabling their use in routine clinical evaluations as either surrogate endpoints or complementary ones to classical signs/symptoms to broaden the etiological learning.

Pityriasis Amiantacea, also known as pseudotinea amiantacea, is a clinical syndrome which affects the scalp, having a reaction pattern reported to occur in several inflammatory dermatoses. The authors seek to establish the correlation between its clinical, dermoscopic and light microscopy features through the analysis of scale- encrusted hair tufts submitted to histological processing.

Papulopustular rosacea (PPR) is a common facial skin disease, characterized by erythema, telangiectasia, papules and pustules. Its physiopathology is still being discussed, but recently several molecular features of its inflammatory process have been identified: an overproduction of Toll-Like receptors 2, of a serine protease, and of abnormal forms of cathelicidin. The two factors which stimulate the Toll-like receptors to induce cathelicidin expression are skin infection and cutaneous barrier disruption: these two conditions are, at least theoretically, fulfilled by Demodex, which is present in high density in PPR and creates epithelial breaches by eating cells. So, the major pathogenic mechanisms of Demodex and its role in PPR are reviewed here in the context of these recent discoveries. In this review, the inflammatory process of PPR appears to be a consequence of the proliferation of Demodex, and strongly supports the hypothesis that: (1) in the first stage a specific (innate or acquired) immune defect against Demodex allows the proliferation of the mite; (2) in the second stage, probably when some mites penetrate into the dermis, the immune system is suddenly stimulated and gives rise to an exaggerated immune response against the Demodex, resulting in the papules and the pustules of the rosacea. In this context, it would be very interesting to study the immune molecular features of this first stage, named "pityriasis folliculorum", where the Demodex proliferate profusely with no, or a low immune reaction from the host: this entity appears to be a missing link in the understanding of rosacea., (© 2011 The Author. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.)

Paraneoplasias are frequently the first sign of a subjacent malignant tumor. Although relatively rare, they need to be recognized by dermatologists to make an early diagnosis and improve the prognosis related especially to the neoplasia. This contribution presents the morphologic aspects and the differential diagnosis of the main paraneoplasias, which include acanthosis nigricans, tripe palms, Leser-Trélat sign, acquired ichthyosis, acquired hypertrichosis lanuginosa, pityriasis rotunda, erythema gyratum repens, palmo-plantar keratoderma, Bazex syndrome, and dermatomyositis, hoping to contribute to the familiarity of dermatologists with the identification and early diagnosis of this group., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Fungal infections of the genitals are probably more common than realized; however, relatively few reports concerning fungal genital infections exist in the literature. In this review, the fungal microbiota of the penis are highlighted, and the epidemiological characteristics of Candida balanitis, penile pityriasis versicolor, and tinea genitalis are addressed. In addition, the benefits of circumcision on male genital infections are included. However, systemic mycoses affecting the penis and/or scrotum will not be addressed in this review. To obtain a reliable diagnosis of genital fungal infections, medical history, clinical examination, and mycological and histological investigations of the lesions are critical.

An adolescent boy presented with isolated, symmetrical, bilateral areolar and periareolar pityriasis versicolor. This extremely rare condition should be considered in the differential diagnosis of light brown patches on the areolae.

A 42-year-old man presented with asymptomatic, sharply-demarcated, round, scaly lesions on his forearms that had been present for several months. A skin biopsy specimen was consistent with pityriasis rotunda. Pityriasis rotunda is a disorder of keratinization, which is thought to be a form of acquired ichthyosis, a delayed presentation of congenital ichthyosis, or a cutaneous manifestation of systemic disease. Patients with pityriasis rotunda may be classified into one of two groups, which are based on ethnicity, number of lesions, family history, and association with systemic diseases. Treatment is challenging, but the use of lactic acid lotion and oral vitamin A has shown some promise.

Background: Pityriasis alba (PA) is a skin disorder characterized by asymptomatic, variably hypopigmented, slightly scaling patches with indistinct margins. It is sometimes difficult to clinically differentiate PA from other hypopigmented disorders such as naevus depigmentosus., Aim: To examine the clinical and histopathological characteristics of PA that are important in differentiating PA from other hypopigmenting disorders., Methods: A clinical survey was carried out on 56 patients with PA. Histopathological features were investigated with immunostains for NKI/beteb antibody, melanoma antigen recognized by T cells (MART)-1 and S-100 protein, and by haematoxylin and eosin and Fontana-Masson stains., Results: Of the 56 PA patients, 10 (18%) had a previous history of atopic dermatitis and 9 (16%) had a solitary lesion. Histopathological study revealed markedly reduced pigment in the epidermis of lesional skin, but no significant difference in melanocyte count was found between lesional and normal skin. Ultrastructurally, degenerative changes in melanocytes and a reduced number of melanosomes within keratinocytes were seen., Conclusion: No significant difference in the number of melanocytes between lesional and normal skin was seen. These findings should be considered when diagnosing and differentiating PA from other hypopigmentary disorders.

Febrile ulceronecrotic Mucha-Habermann disease is a severe variant of pityriasis lichenoides et varioliformis acuta characterized by the sudden onset of ulceronecrotic skin lesions and associated with high fever and systemic symptoms. We report here a case of a 20-year-old woman in whom the disease started as pityriasis lichenoides et varioliformis acuta and evolved to febrile ulceronecrotic Mucha-Habermann disease. Almost 90% of the body surface was involved, together with high fever and malaise. Steroids alone proved to be an insufficient therapeutic procedure. The remission achieved was attributed to the use of methotrexate. To our knowledge, only 39 cases of febrile ulceronecrotic Mucha-Habermann disease have been reported in the literature to date.

Background: Use of topical corticosteroids for the treatment of pityriasis alba is limited by their potential side-effects, such as skin atrophy especially with long-term use on the face. Pimecrolimus cream 1% is a topical calcineurin inhibitor that has anti-inflammatory properties, lacks the cutaneous side-effects associated with steroids, and provide a potential benefit for the treatment of pityriasis alba., Methods: This 10-patient, prospective, single-arm, open-label, single-center, 12-week, investigator-initiated proof of concept study assessed the efficacy, safety, and patient acceptance of pimecrolimus cream 1% twice daily. In addition to pimecrolimus cream, patients used facial emollient containing SPF 15 sunscreen and mild soap-free cleanser. Efficacy assessments were Investigator Global Assessment (IGA) of disease severity and evaluation of uneven skin color, scaling, eczema, follicular keratosis, and pruritus. All efficacy assessments were reported on a 4-point scale (0 = none to 3 = severe)., Results: Of the 10 patients enrolled (aged: 12-35 years), all had intensive sun-exposure, 90% had skin type IV-V, and 80% completed the 12-week treatment. At baseline, mean IGA was 1.20 (mild-moderate), uneven skin color was 2.3 (moderate-severe) and scaling was 1.2 (mild). IGA decreased to 0.25 by week 12, uneven skin color improved by week 3 with near complete resolution by week 12 (mean = 0.38) and scaling resolved at week 3. Pruritus, eczema, and follicular keratosis remained at low levels from baseline throughout the course of the study. Patients consistently reported satisfaction with the treatment ("satisfied" or "very satisfied"). No adverse events were reported., Conclusions: Pimecrolimus cream 1% may represent an alternative for the treatment of pityriasis alba.

Background: Pityriasis alba (PA) is a frequent reason for dermatological consultation because of its chronic course, tendency to relapse and aesthetic impact., Objectives: In view of its strong association with atopic dermatitis, the objective of this open-label study was to assess the efficacy and safety of tacrolimus ointment in the treatment of PA compared with the efficacy of moisturizers., Patients/methods: The study population consisted of 60 individuals of phototype III or IV according to Fitzpatrick's classification, aged 6-21 years. Patients were randomly assigned to one of two groups. Subjects in group A were instructed to apply tacrolimus ointment 0.1% twice daily, 12 h apart, on all hypopigmented macules. Standard moisturizers with SPF 20 sunscreen were used on all lesions applied at least 30 min apart from the tacrolimus ointment. Subjects in group B used solely the same moisturizers with sunscreen. Hypopigmented areas were evaluated at baseline and weeks 0, 3, 6 and 9 by investigators for scaling, hypopigmentation and pruritus on a scale of 0-3. Patient satisfaction was also recorded on a scale of 0-3. All adverse effects were recorded., Results: A statistically significant improvement through time, in hypopigmentation, pruritus and scaling was observed in both groups during the course of 9 weeks. Hypopigmentation resolved from a baseline score of 2.38+/-0.64 to 1.15+/-0.54 at week 3, 0.46+/-0.51 at week 6 and 0.00+/-0.00 at week 9 for the group applying tacrolimus ointment 0.1%. The difference in improvement between the two groups was statistically significant on all three assessments for hypopigmentation (P<0.001), and for pruritus on week 6 and 9 assessments (P<0.05). Three patients (11.5%) in the tacrolimus group reported a mild transient sensation of burning. All patients in the tacrolimus group reported they were completely satisfied or just satisfied with the treatment compared with only 50% of patients using the placebo., Conclusions: Tacrolimus ointment 0.1% appears to be an effective and safe treatment for PA.

We report the cases of five female patients with high skin phototype affected by relapsing, hypochromic, non-scaling macules occurring after the summer on the back and spreading over large areas of skin. Histological features disclosed decreased epidermal melanin. Psoralen plus ultraviolet A (PUVA) treatment proved to be beneficial, but new relapses were noted after stopping treatment. Clinical and histological features were consistent with the diagnosis of 'progressive and extensive hypomelanosis' described by Guillet in persons of mixed racial background. We discuss the differential diagnosis of the latter entity with respect to the other idiopathic acquired primitive hypomelanosis and hypothesize an overlapping with the so-called extensive pityriasis alba (EPA).

Pityriasis versicolor (PV) is a widespread dermatomycosis caused by yeasts. Erythrasma is a superficial bacterial skin disease affecting the major folds of the body, particularly the groin. We report the case of a 45-year-old man, affected by PV, exclusively localized in the inguinal folds and in the inner surface of the thighs, characterized by lesions clinically reproducing erythrasma. The authors underline the possibility that PV mimics erythrasma and vice versa, especially in those countries in which both diseases are quite common, and stress the importance of performing a simple mycological examination to avoid gross diagnostic and therapeutic errors.

Dandruff (also called Pityriasis capitis) is a seborrhoeic dermatitis of the scalp. It has been correlated with the pathological colonization of the scalp with yeast from the genus Malassezia; this illness has a worldwide distribution and represents 25% of all scalp dermatosis cases. It has been demonstrated that the extract obtained from leaves of the plant Solanum chrysotrichum possesses biological activity against dermatophytes and yeast. Different steroidal saponins with antimycotic activity have been isolated from the active extract. Clinical trials with standardized extracts prepared with this vegetal species report high rates of clinical and mycological effectiveness in the treatment of Tinea pedis,without producing secondary effects. The aim of this randomized, double blind and controlled clinical study, was to compare the therapeutic effectiveness and tolerability of a shampoo containing a standardized extract of S. chrysotrichum (applied every third day, for 4 weeks), against 2% ketoconazole in the topical treatment of Pityriasis capitis. From a total of 120 patients with the clinical diagnosis of Pityriasis capitis, 14 subjects were eliminated because the presence of Malassezia was not proved, an-other two patients withdrew from the study due to non-medical causes and one more withdrew because Tinea capitis was diagnosed. Therefore, the final analysis included 51 subjects in the experimental group and 52 in the control; in 45.6% of the cases M. furfur was identified as the pathogenic agent, in 44.66% M. globosa was isolated, and 9.71 % of the patients had a mixed infestation. At the end of the treatment period, the prepared phytopharmaceutical with the standardized extract from S. chrysotrichum achieved a clinical effectiveness (total absence of signs and symptoms produced by Pityriasis capitis) of 92.16%;the mycological effectiveness (absence of Malassezia spp. in the direct examination and culture) was 68.63 %; whilst the tolerability (absence of side effects that prompt subjects to abandon the treatment) was 100%. The therapeutic success (clinical and mycological effectiveness plus tolerability) was 64.71%. The comparison of these results with that obtained from the group treated with 2% ketoconazole, showed no significant differences (Z2, p >0.23). These results show the therapeutic effectiveness and tolerability of the standardized extract from S. chrysotrichum on the local treatment of Pityriasis capitis associated with the yeast of the genus Malassezia.

Background: Studies on pityriasis amiantacea (PA) in the literature are limited and mostly retrospective. We prospectively analyzed the clinical and etiopathologic factors in a large series of PA diagnosed at our department within a defined period (2000-01)., Methods: All PA patients who attended our department were evaluated clinically and underwent bacteriologic, mycologic, and histopathologic examinations. Forty healthy control persons were similarly subjected to bacteriologic and mycologic investigations of their scalp hairs., Results: A total of 85 PA patients were collected and studied. Pathological diagnosis of scalp psoriasis was confirmed in 35.3% of cases. Eczematous features suggesting a diagnosis of seborrheic and atopic dermatitis were detected in 34.2%. Diagnosis of tinea capitis, diagnosed by potassium hydroxide preparation, fungal culture, and periodic-acid Schiff staining, was detected in 12.9% of the PA patients. Staphylococcus isolates were detected in 96.5% of the PA patients compared with 15% in healthy persons as the control (P > 0.00001)., Conclusions: Pityriasis amiantacea represents a particular reaction pattern of the scalp to various inflammatory scalp diseases. The most frequent skin diseases associated with PA are psoriasis and seborrheic dermatitis. It is important to keep the diagnosis of tinea capitis in mind when evaluating PA patients. Staphylococci on the scalp could participate in the pathogenesis of PA.

Objective: To determine the prevalence and severity of seborrheic dermatitis and pityriasis capitis in Australian preschool-aged children., Design: A stratified cross-sectional skin survey using cluster sampling of centers throughout Victoria, Australia., Setting: The study population included children attending child care centers, preschools, and Maternal and Child Health Centers, with the reference population being Australian children 5 years and younger., Participants: Of the 1,634 children in the original sample, 1.116 children aged 11 days to 5 years 11 months were included in the study., Intervention: Parents completed a questionnaire recording demographic information and personal and family history of skin problems and related diseases. A dermatologist performed a total skin examination, including the diaper area for children younger than 12 months., Main Outcome Measure: The age- and sex-specific prevalence rates and site and severity of seborrheic dermatitis and pityriasis capitis were measured., Results: The overall age- and sex-adjusted prevalence of seborrheic dermatitis was 10.0% (95% confidence interval [CI], 8.2%-11.7%): 10.4% (95% CI, 7.8%-12.9%) in boys and 9.5% (95% CI, 7.0%-12.0%) in girls. This was highest in the first 3 months of life, decreasing rapidly by the age of 1 year, after which it slowly decreased over the next 4 years. Most (71.9%) had disease classified as minimal to mild. Pityriasis capitis occurred in 41.7% (95% CI, 38.8%-44.6%) of the 1,116 children examined, with 85.8% categorized as minimal to mild only., Conclusions: Seborrheic dermatitis and pityriasis capitis are common in early childhood. Most children have minimal to mild disease that would require little if any treatment. Education programs directed at those caring for preschool-aged children are needed to provide information on simple preventative measures and treatment, if necessary, that could easily reduce the morbidity associated with these very common conditions.

Background: The aetiology of pityriasis alba (PA), a common dermatosis in childhood, is still controversial. The objective of this study was to assess the possible aetiopathogenic factors of this disease in infants., Methods: Forty-four patients with PA and 31 healthy children were examined and compared. Personal hygiene habits, sun exposure, presence of Staphylococcus aureus in nasal fossae and presence of major or minor signs of atopy were assessed during anamnesis and physical examination. Susceptibility to ultraviolet (UV) B radiation was measured by the onset of a contact hypersensitivity reaction to diphenylcyclopropenone in individuals sensitized in previously irradiated areas., Results: The prevalence of PA was higher in individuals with darker skin, in high phototype categories, as well as in males. The number of daily baths and sun exposure between 10.00 h and 15.00 h were significantly higher in the PA group when compared with controls (P = 0.03 and P = 0.0015, respectively). The presence of atopy signs was more common in pityriasis patients (P = 0.002). Susceptibility to UVB radiation was 29.6% in the PA group vs. 29.0% in the control group; nevertheless, important differences were found after stratification in order to control possible confounding factors. The presence of S. aureus in the nostrils was equal in both groups., Conclusions: Our results confirm that PA, in our population, is more prevalent in males and in individuals in higher phototype categories. In those with inadequate personal hygiene and sun exposure habits the disease is more accentuated, demonstrating that the xerosis presenting in individuals with atopic diathesis is an important element in the development of the disease. S. aureus is not an important aetiopathogenic factor in PA. Susceptibility to UVB becomes important when related to the patient's phototype.

Pityriasis Rotunda is a dermatosis well known in Japan and Black Africa. Its unusual in Europe and North Africa. Several authors consider that Pityriasis Rotunda is an acquired ichtyose and that it represents a real paraneoplastic syndrome. We report the case of Tunisian men suffering from a Pityriasis Rotunda associated to a dilatation of branch.