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Sphingomyelinase D (SMase D), the main toxic component of Loxosceles venom, has a well-documented role on dermonecrotic lesion triggered by envenomation with these species; however, the intracellular mechanisms involved in this event are still poorly known. Through differential transcriptomics of human keratinocytes treated with L. laeta or L. intermedia SMases D, we identified 323 DEGs, common to both treatments, as well as upregulation of molecules involved in the IL-1 and ErbB signaling. Since these pathways are related to inflammation and wound healing, respectively, we investigated the relative expression of some molecules related to these pathways by RT-qPCR and observed different expression profiles over time. Although, after 24 h of treatment, both SMases D induced similar modulation of these pathways in keratinocytes, L. intermedia SMase D induced earlier modulation compared to L. laeta SMase D treatment. Positive expression correlations of the molecules involved in the IL-1 signaling were also observed after SMases D treatment, confirming their inflammatory action. In addition, we detected higher relative expression of the inhibitor of the ErbB signaling pathway, ERRFI1, and positive correlations between this molecule and pro-inflammatory mediators after SMases D treatment. Thus, herein, we describe the cell pathways related to the exacerbation of inflammation and to the failure of the wound healing, highlighting the contribution of the IL-1 signaling pathway and the ERRFI1 for the development of cutaneous loxoscelism., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A 63-year-old man presented with two days of palpable purpura over the right anterior shin and calf with notable point tenderness on the distal mid-calf without any palpable deep abnormality. Localized right calf pain worsened with walking and was associated with headache, chills, fatigue, and low-grade fevers. A punch biopsy of the anterior right lower leg showed necrotizing neutrophilic vasculitis of superficial and deep vessels. Direct immunofluorescence showed non-specific focal granular deposition of C3 within vessel walls. Three days after presentation, a live spider was found and microscopically identified as a male hobo spider. The patient suspected the spider arrived via packages shipped from Seattle, Washington. The patient was treated with a prednisone taper with full resolution of his cutaneous symptoms. Given the unilaterality of his symptoms and otherwise unexplained etiology, the patient was diagnosed with acute unilateral vasculitis secondary to hobo spider bite. Microscopic examination is required for identification of hobo spiders. Although not deadly, there have been several reports of cutaneous and systemic reactions resulting from hobo spider bites. Our case illustrates the importance of considering hobo spider bites in areas outside of their native regions, as they are known to travel in packaged items.

Context: In recent years, the Noble false widow spider Steatoda nobilis (Thorell, 1875) has expanded its range globally and may represent a potential threat to native ecosystems and public health. Increasing numbers in synanthropic habitats have led to more human encounters and envenomations. Steatoda nobilis bites were previously classed as medically significant with similarities to bites from true black widows of the genus Latrodectus but deemed milder in onset, with symptoms generally ranging from mild to moderate., Case Details: In this manuscript we present 16 new cases of S. nobilis envenomations bringing the total number of confirmed cases reported in the literature to 24. We report new symptoms and provide discussion on the contributing factors to pathology following bites by S. nobilis ., Discussion: We report a range of pathologies including necrosis, Latrodectus -like envenomation symptoms that include debilitating pain, tremors, fatigue, nausea, hypotension, and vectored bacterial infections including cellulitis and dermatitis. Symptoms ranged from mild to severe, requiring hospitalisation in some cases.

We report a case of envenomation by Steatoda borealis (Hentz, 1850) in Connecticut in late spring 2021. The bitten subject was a 60-yr-old female Caucasian. The bite occurred upon disturbing some books in her basement. She reported a painful stinging bite on her finger followed by the formation of an erythematous macule at the site of the bite which was gone the next day. There was no sign of necrosis. The spider was recovered directly at that time. The victim reported that later that night she experienced heart palpitations. This is the first report of envenomation by S. borealis, a common spider in Connecticut., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America.All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Loxosceles reclusa (LR), commonly known as the brown recluse spider, is endemic to the south central United States. We present a case of LR envenomation in a healthy adult male outside the usual geographic range, with atypical dermatologic and delayed, prolonged systemic loxoscelism (LX). This case demonstrates the importance of expanding the depth of knowledge of LR envenomations., Case Report: A previously healthy 27 year-old male presented to an emergency department (ED) in central Virginia two hours after a LR envenomation to his left proximal arm. He was treated with diphenhydramine and discharged on oral methylprednisolone for a 5-day taper. On post-bite Days 1 and 2, the patient developed subjective fevers, chills, arthralgias, and myalgias, followed by a blanching, pruritic, morbilliform rash throughout his trunk and lower extremities. Post-bite Day 3, the patient presented to the ED again because of marked erythema of face and the right lateral thigh, and posterior and anterior trunk. Vital signs and laboratory analysis were generally unremarkable. The patient was observed overnight, and discharged with a prescription for prednisone 60 mg per day. On post-bite Day 7, the patient noted a petechial rash on the palms and soles and returned to the ED with a fever of 102.6 °F, a heart rate of 130 beats per minutes, and systolic blood pressure ranging 80-90 mmHg. After considering this may be an atypical presentation of LX, corticosteroids were increased to methylprednisolone 1 mg/kg IV every 6 h. The patient's condition slowly improved and he was discharged on post-bite Day 10. On post-bite Day 24, he had nearly complete resolution of skin findings., Conclusions: LR envenomation can cause a variety of dermatological and systemic manifestations of toxicity. It is critical for toxicologists to be aware of the variety of presentations and findings to appropriately assess and treat LX.

Spiders have long been admired for the beauty of their webs. They are celebrated in popular culture as well as in medical eponyms. This contribution provides the historical background for three spider-related eponyms: nevus araneus (spider angioma), arachnodactyly, and the arachnoid mater. Nevus araneus was first named and described by Sir Erasmus Wilson in 1842. Arachnodactyly was described in 1896 by Antoine Marfan using the term pattes d'araignée, which means spider legs. In 1902, Emile Charles Achard proposed the term arachnodactyly for this clinical finding. The arachnoid mater had been named in 1699 by Frederik Ruysch. The clinical management of spider bites from the only two dangerous venomous spiders within the United States, the black widow spider (Latrodectus mactans) and the brown recluse spider (Loxosceles reclusa), is reviewed., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Loxoscelism is a systemic inflammatory reaction in response to a brown recluse spider bite (BRSB). In this case we describe a patient with a heightened inflammatory response to a presumed BRSB, with Coomb's positive hemolysis, cytoplasmic antineutrophil cytoplasmic antibody (cANCA) vasculitis, and features of hemophagocytic lymphohistiocytosis (HLH). A 24-y-old female presented with sudden pain and swelling to her lower back, nausea, fever, and tachycardia after a presumed BRSB. Hemolysis began on hospital day 3 (15.9 g·dL -1 ) with a nadir on hospital day 5 (6.3 g·dL -1 ). She had an lactate dehydrogenase of 1415 U·L -1 , ferritin of 15534 ng·mL -1 , persistent fever, and signs of bone marrow suppression despite hemolysis, with thrombocytopenia (100,000 μL -1 ) and an inadequate reticulocyte response (1.7%) suggestive of HLH. The patient's blood was Coomb's and cANCA/antiproteinase 3 positive. She had signs of toxin-induced vasculitis, with respiratory failure requiring bilevel positive airway pressure, radiographs with bilateral pulmonary infiltrates, and a desquamating rash. She received 6 U of packed red blood cells, furosemide for pleural and pericardial effusions, antibiotics, and symptomatic treatment during the acute phase of her illness. Hemolysis improved without glucocorticoids by hospital day 6. The patient demonstrated a dysregulated immunologic and complement-mediated response to the presumed BRSB. The triad of Coomb's positive hemolysis, cANCA vasculitis, and HLH-like reaction associated with a presumed BRSB is described for the first time in the literature and brings up questions for future research regarding the role of immune modulators and complement inhibitors in the treatment of severe loxoscelism as well as the genetic factors that predispose certain individuals to such reactions., (Copyright © 2019 Marketing EDGE.org. Published by Elsevier Inc. All rights reserved.)

Brown recluse spider bites can cause local and systemic signs, including rash, dermonecrosis, edema, hemolysis, and acute kidney failure. These are mostly attributed to sphingomyelinase D, the main toxin. To evaluate the severity of the disease in pediatric patients with and without neutropenia, we retrospectively reviewed records of patients treated at St. Jude Children's Research Hospital between 1970 and 2015 and identified 19 patients who met the inclusion criteria. Variables of interest included the type of underlying illness, presence of neutropenia, number of days of hospitalization, disease signs and outcome of the bite, and treatments administered. We used descriptive statistics to summarize the manifestations and severity of spider bites in patients with and without neutropenia. Six patients experienced pain from the bite, 11 had erythema, 7 developed edema, and 5 had fever. The response to spider bites in neutropenic patients was no milder than that in non-neutropenic individuals. Six patients developed systemic complications. Compared with non-neutropenic patients, neutropenic patients had antibiotics prescribed more often and experienced longer hospital stays. Spider bites do not seem to have a different clinical course in neutropenic patients. Therefore, a conservative approach may be best for these patients, with close monitoring and local wound care.

We present a case from Valencia, Spain, of a 25-year-old woman who presented with a painful erythematous skin lesion, initially diagnosed as cellulitis. The lesion was unresponsive to antibiotic treatments and progressed into a hemorrhagic blister with necrotic ulcer formation. Posterior collection of a spider from the patient's home and expert identification of the spider as Loxosceles rufescens was achieved, establishing the diagnosis of probable cutaneous loxoscelism. Symptomatic treatment, general wound care and ultimately surgery, resulted in complete recovery with minor residual scarring. This case illustrates some of the difficulties encountered in the diagnosis and treatment of loxoscelism and adds to the increasing reports of loxoscelism in the Mediterranean Basin., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The Mediterranean recluse spider, Loxosceles rufescens (Dufour, 1820) (Araneae: Sicariidae) is a cosmopolitan spider that has been introduced in many parts of the world. Its bite can be dangerous to humans. However, the potential distribution of this alien species, which is able to spread fairly quickly with human aid, is completely unknown. Using a combination of global and regional niche models, it is possible to analyse the spread of this species in relation to environmental conditions. This analysis found that the successful spreading of this species varies according to the region invaded. The majority of populations in Asia are stable and show niche conservatism, whereas in North America this spider is expected to be less successful in occupying niches that differ from those in its native region and that do not support its synanthropic way of living., (© 2018 The Royal Entomological Society.)

Spider venom is being researched for its potential use in applications such as insecticides, to better understand the dynamics of neuronal ion channel physiology and as potential remedies to counter antibiotic resistant bacteria. However, spider venom is more widely known for its ability to cause deleterious reactions after toxic envenomations in humans. In this short review, the "dark" side of spider venoms is presented to provide a counterbalance to the investigations of the positive potential that venoms can or might improve our world or its understanding. The goal was to present a short primer on species having clinical consequences in humans rather than be an exhaustive review of all spiders of medical importance., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objective: The noble false widow Steatoda nobilis is the only medically significant spider known to occur in the British Isles and Ireland, with a single case of steatodism ever reported from Great Britain. We present here five new cases of envenomations by S. nobilis, three from Ireland and two from Great Britain and describe symptoms not previously reported for the genus Steatoda., Case Presentation: Four adult males and one adult female with confirmed S. nobilis bites reported their symptoms to the authors. General practitioner chart was obtained for case #3. In all five cases, envenomations were immediately followed by a sharp and prolonged onset of pain, mild to extensive erythema and localised to extensive swelling around the bite site. Additional symptoms include moderate to intense pruritus, vasodilation of the capillaries around the bite site and a possible minor necrotic wound., Conclusion: In all cases, symptoms subsided within 48-72 h and no further complications were reported. Envenomations by S. nobilis seem to produce symptoms similar (but not identical) to those previously reported from other Steatoda sp. Considering their benign outcome, envenomations by S. nobilis should still be regarded as of moderate medical importance, requiring monitoring and pain management strategies.

Loxosceles rufescens is a circum-Mediterranean spider species, potentially harmful to humans. Its native area covers the Mediterranean Basin and Near East. Easily spread with transported goods, it is meanwhile an alien and invasive species to nearly all other continents and many islands. This species occurs in semi-arid steppe-like habitats, typically under stones and in cavities, which enables it to settle inside buildings when invading the synanthropic environment. This review analyses the literature of L. rufescens bites to humans (38 publications) of which only 11 publications refer to 12 verified spider bites (11% of the reported bites). Two published allegedly deadly spider bites (Thailand 2014 and Italy 2016) involve non-verified spider bites and are thus not reliable. The symptoms and therapy of these 11 verified bites are described: only five cases showed moderate systemic effects, nine cases developed necrosis, four cases needed surgical debridement, all cases healed without complications within a few weeks. In conclusion, L. rufescens is a spider species globally spread by human activity, it rarely bites humans and the bites are less harmful than often described. There is no known fatal issue., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Bites by Loxosceles spiders (also known as recluse spiders or brown spiders) can cause necrotic ulcerations of various sizes and dimensions. The current standard of care for brown spider bites includes analgesics, ice, compression, elevation, antihistamines, and surgical debridement. Hyperbaric oxygen therapy (HBOT) in the treatment of brown spider bites has been administered in the early stage of ulceration, or 2 to 6 days after the bite. Unfortunately, the diagnosis of spider bite-related ulcers is often delayed and weeks or months may elapse before HBOT is considered., Objective: To evaluate the effect of HBOT on nonhealing wounds caused by brown spider bites in the late, chronic, nonhealing stage., Methods: Analysis of 3 patients with brown spider-bite healing wounds treated at The Sagol Center for Hyperbaric Medicine and Research in Israel. Patients presented 2 to 3 months after failure of other therapies including topical dressings, antibiotics, and corticosteroids. All patients were treated with daily 2 ATA (atmospheres absolute) with 100% oxygen HBOT sessions., Results: All 3 patients were previously healthy without any chronic disease. Their ages were 30, 42, and 73 years. They were treated once daily for 13, 17, and 31 sessions, respectively. The wounds of all 3 patients healed, and there was no need for additional surgical intervention. There were no significant adverse events in any of the patients., Conclusions: Microvascular injury related to brown spider bites may culminate in ischemic nonhealing wounds even in a relatively young, healthy population. Hyperbaric oxygen therapy should be considered as a valuable therapeutic tool even months after the bite.

We have previously demonstrated that Phoneutria nigriventer venom (PNV) causes blood-brain barrier (BBB) breakdown, swelling of astrocytes end-feet and fluid permeation into brain interstitium in rats. Caveolae and water channels respond to BBB alterations by co-participation in shear stress response and edema formation/resolution. Herein, we showed post-natal developmental-related changes of two BBB-associated transporter proteins: the endothelial caveolin-1 (Cav-1), the major scaffolding protein from caveolae frame, and the astroglial aquaporin-4 (AQP4), the main water channel protein expressed in astrocytic peri-vascular end-feet processes, in the hippocampus of rats intraperitoneally-administered PNV. Western blotting protein levels; immunohistochemistry (IHC) protein distribution in CA1, CA2, and CA3 subfields; and gene expression by Real Time-Polymerase Chain Reaction (qPCR) were assessed in post-natal Day 14 (P14) and 8-10-week-old rats over critical periods of envenomation. The intensity and duration of the toxic manifestations indicate P14 neonate rats more vulnerable to PNV than adults. Histologically, the capillaries of P14 and 8-10-week-old rats treated with PNV showed perivascular edema, while controls did not. The intensity of the toxic manifestations in P14 decreases temporally (2 > 5 > 24 h), while inversely the expression of AQP4 and Cav-1 peaked at 24 h when clinically PNV-treated animals do not differ from saline controls. IHC of AQP4 revealed that hippocampal CA1 showed the least expression at 2 h when toxic manifestation was maximal. Subfield IHC quantification revealed that in P14 rats Cav-1 peaked at 24 h when toxic manifestations were absent, whereas in 8-10-week-old rats Cav-1 peaked at 2 h when toxic signs were highest, and progressively attenuated such increases until 24 h, remaining though significantly above baseline. Considering astrocyte-endothelial physical and functional interactions, we hypothesize that age-related modulations of AQP4 and Cav-1 might be linked both to changes in functional properties of astrocytes during post-natal development and in the BBB breakdown induced by the venom of P. nigriventer ., Competing Interests: The authors declare no conflict of interest.

Spider poisoning is rare in Europe, with very few reported cases in the literature. Recluse spider (genus Loxosceles) bites may lead to cutaneous and systemic manifestations known as loxoscelism. We report the second known case of spider bite poisoning in Malta caused by Loxosceles rufescens (Mediterranean recluse spider). A young adult female presented with localised erythema and pain on her left thigh after a witnessed spider bite. Over a few days, the area developed features of dermonecrosis together with systemic symptoms, including fever, fatigue and a generalised erythematous eruption. She was managed by a multidisciplinary team and the systemic symptoms resolved within 6 days, while the skin lesion healed with scarring within 2 months. A recluse spider bite should be considered in patients with dermonecrosis. Although spider bite poisoning is uncommon in Europe, it is important to diagnose and manage it appropriately since it could lead to potentially serious sequelae., (2016 BMJ Publishing Group Ltd.)

Numerous studies have shown that the venom of Phoneutria nigriventer (PNV) armed-spider causes excitotoxic signals and blood-brain barrier breakdown (BBBb) in rats. Nitric oxide (NO) is a signaling molecule which has a role in endothelium homeostasis and vascular health. The present study investigated the relevance of endothelial NO synthase (eNOS) uncoupling to clinical neurotoxic evolution induced by PNV. eNOS immunoblotting of cerebellum lysates processed through low-temperature SDS-PAGE revealed significant increased monomerization of the enzyme at critical periods of severe envenoming (1-2 h), whereas eNOS dimerization reversal paralleled to amelioration of animals condition (5-72 h). Moreover, eNOS uncoupling was accompanied by increased expression in calcium-sensing calmodulin protein and calcium-binding calbindin-D28 protein in cerebellar neurons. It is known that greater eNOS monomers than dimers implies the inability of eNOS to produce NO leading to superoxide production and endothelial/vascular barrier dysfunction. We suggest that transient eNOS deactivation and disturbances in calcium handling reduce NO production and enhance production of free radicals thus contributing to endothelial dysfunction in the cerebellum of envenomed rats. In addition, eNOS uncoupling compromises the enzyme capacity to respond to shear stress contributing to perivascular edema and it is one of the mechanisms involved in the BBBb promoted by PNV., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Importance: Bites from the brown recluse spider (BRS) can cause extreme pain. We propose cytokine release as a cause of the discomfort and a central mechanism through glial cell upregulation to explain measured pain levels and time course., Observations: Twenty-three BRS bites were scored at a probable or documented level clinically, and an enzyme-linked immunosorbent assay was used to confirm the presence of BRS venom. The mean (SD) pain level in these cases 24 hours after the spider bite was severe: 6.74 (2.75) on a scale of 0 to 10. Narcotics may be needed to provide relief in some cases. The difference in pain level by anatomic region was not significant. Escalation observed in 22 of 23 cases, increasing from low/none to extreme within 24 hours, is consistent with a cytokine pain pattern, in which pain increases concomitantly with a temporal increase of inflammatory cytokines., Conclusions and Relevance: These findings in BRS bites support the hypothesis of cytokine release in inflammatory pain. A larger series is needed to confirm the findings reported here. The extreme pain from many BRS bites motivates us to find better prevention and treatment techniques.

The Australian white-tailed spiders ("WTS"; Lamponidae: notably Lampona cylindrata &Lampona murina) have a continuing reputation on Internet sites as a cause of skin ulceration, labelled "necrotic arachnidism", despite an increasing number of peer-reviewed publications debunking this reputation, with >135 confirmed cases now reported without any evidence of necrosis. We present here a case of confirmed WTS bite in a 42-year old male, followed for over a month, with photos of bite site signs and no development of skin ulceration/necrosis. The patient was initially alarmed by information on the Internet suggesting local necrosis would result from the bite. We discuss the evolution of knowledge about bites by the WTS, and the persistence of misconceptions about their factually mild medical significance., (Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.)

The Loxosceles genus spiders (the brown spiders) are encountered in all the continents, and the clinical manifestations following spider bites include skin necrosis with gravitational lesion spreading and occasional systemic manifestations, such as intravascular hemolysis, thrombocytopenia and acute renal failure. Brown spider venoms are complex mixtures of toxins especially enriched in three molecular families: the phospholipases D, astacin-like metalloproteases and Inhibitor Cystine Knot (ICK) peptides. Other toxins with low level of expression also present in the venom include the serine proteases, serine protease inhibitors, hyaluronidases, allergen factors and translationally controlled tumor protein (TCTP). The mechanisms by which the Loxosceles venoms act and exert their noxious effects are not fully understood. Except for the brown spider venom phospholipase D, which causes dermonecrosis, hemolysis, thrombocytopenia and renal failure, the pathological activities of the other venom toxins remain unclear. The objective of the present review is to provide insights into the brown spider venoms and loxoscelism based on recent results. These insights include the biology of brown spiders, the clinical features of loxoscelism and the diagnosis and therapy of brown spider bites. Regarding the brown spider venom, this review includes a description of the novel toxins revealed by molecular biology and proteomics techniques, the data regarding three-dimensional toxin structures, and the mechanism of action of these molecules. Finally, the biotechnological applications of the venom components, especially for those toxins reported as recombinant molecules, and the challenges for future study are discussed., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Envenomation by the Loxosceles spider causes loxoscelism, a pattern of signs and symptoms that primarily manifests in the dermonecrotic form. Our studies have shown that a mouse subcutaneous sponge implantation model may be useful in evaluating the effects of Loxosceles similis venom. This model provides an ideal microenvironment in which to study loxoscelism; however, it is still important to evaluate its pathogenesis and to observe the effects of L. similis venom for longer time periods than those in previous studies of this model. The aims of this study are: (1) to histologically characterize the effects of L. similis crude venom in a subcutaneous sponge implant; (2) to quantify the mast cells present in the implant and to measure their degranulation activity; (3) to quantify collagen subtypes I and III; and (4) to verify, quantify, and evaluate the effects of apoptosis in the implant on the pathogenesis of loxoscelism at 1 h, 4 h, and 24 h after injecting the venom. Thirty Swiss mice (6-8 weeks old, male) were subcutaneously implanted with polyester-polyurethane sponge discs. Fourteen days post-implantation, the animals were divided into six groups (5 animals per group): three control groups (C1h, C4h, and C24h), in which the mice received 30 μl injections of intra-implant saline, and three treated groups (T1h, T4h, and T24h), in which the mice received 30 μl (0.5 μg) injections of L. similis crude venom at 1 h, 4 h, and 24 h intervals. After each time interval, the animals were euthanized, and the implants were harvested and processed for light and electron microscopic analyses. The following results were observed in the implants harvested from the treated groups: acute inflammation with marked edema, thrombus, and vasculitis, as well as increased levels of mast cells and mast cell degranulation, and apoptosis in giant cells. Furthermore, degradation of collagen types I and III was observed. An analysis of the ultrastructure revealed apoptosis in various cell types. The present results suggest that apoptosis in some cell types associated with an increase in mast cell degranulation and the degradation of collagen fibers are important in the pathogenesis of loxoscelism therefore may explain the difficulty in repairing the ulcer is commonly observed in severe cases of loxoscelism cutaneous in humans., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

This study compiled 33 verified spider bites from the state of Oregon (USA). The initial goal was to amass a series of bites by the hobo spider to assess whether it possesses toxic venom, a supposition which is currently in a contested state. None of the 33 bites from several spider species developed significant medical symptoms nor did dermonecrosis occur. The most common biters were the yellow sac spider, Cheiracanthium mildei (N = 10) and orb-weavers of the genus Araneus (N = 6). There were 10 bites from three genera of funnel web spiders of the family Agelenidae including one hobo spider bite and one from the congeneric giant house spider which is readily confused as a hobo spider. The hobo spider bite resulted in pain, redness, twitching in the calf muscle and resolved in 12 h. Also generated from this study were possibly the first records of bites from spiders of the genera Callobius (Amaurobiidae) and Antrodiaetus (Antrodiaetidae), both with minor manifestations., (Published by Elsevier Ltd.)

Literature on bird spider or tarantula bites (Theraphosidae) is rare. This is astonishing as they are coveted pets and interaction with their keepers (feeding, cleaning the terrarium or taking them out to hold) might increase the possibility for bites. Yet, this seems to be a rare event and might be why most theraphosids are considered to be harmless, even though the urticating hairs of many American species can cause disagreeable allergic reactions. We are describing a case of a verified bite by an Indian ornamental tree spider (Poecilotheria regalis), where the patient developed severe, long lasting muscle cramps several hours after the bite. We present a comprehensive review of the literature on bites of these beautiful spiders and conclude that a delayed onset of severe muscle cramps, lasting for days, is characteristic for Poecilotheria bites. We discuss Poecilotheria species as an exception from the general assumption that theraphosid bites are harmless to humans., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

During a two-year study, all spider bites recorded by Swiss primary care physicians were reported to the Swiss Toxicological Information Centre and all collected spiders were identified. A total of 14 verified spider bites were recorded, involving five species from four families: Zoropsis spinimana (five cases), Cheiracanthium punctorium (four cases), Tegenaria atrica (three cases) and one case of Malthonica ferruginea (= Tegenaria ferruginea) (both Agelenidae), and one case of Amaurobius ferox (Amaurobiidae). The bites of all spider species produced relatively mild symptoms. Local symptoms such as moderate to severe pain, circumscribed swelling and redness were the only effects in most cases. Systemic symptoms were rare. There was complete recovery in all cases and all lesions healed completely without further damage or secondary disorders. Following a review of the European spider bite literature, the number of spider species capable of biting humans in Europe is considered to be much larger than could be concluded from this study. Most spider bites are restricted to species living synanthropically, thus promoted by climate and habitat change. The annual frequency of spider bites in Switzerland is estimated at 10-100 bites per million inhabitants, but this is predicted to increase due to the continuous arrival of new alien species, many of which have a high potential to establish in urban areas., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Erythema multiforme (EM) is an immune-mediated mucocutaneous eruption characterized by symmetrically distributed, polymorphic targetoid lesions, mostly on the distal parts of the extremities. It occurs mostly in the setting of an infection in certain predisposed individuals. A 30-year-old pregnant woman was presented with a necrotic erythematous lesion on her right thigh following a spider bite. As she was pregnant for 16 weeks, no systemic medication was given. On the 8th day of the spider bite an erythematous vesicular and targetoid rash was seen on the distal parts of her extremities. Based on the clinical and histopathological findings, lesions were diagnosed as EM. She had not used any medication for 4 months and she gave no prior history of herpetic infection. So her EM lesions were thought to be an ID reaction most probably due to the spider bite. As far as we know, this is the first reported case of EM induced by a spider bite.

Background: The spider family Sicariidae includes two genera, Sicarius and Loxosceles. Bites by Sicarius are uncommon in humans and, in Brazil, a single report is known of a 17-year old man bitten by a Sicarius species that developed a necrotic lesion similar to that caused by Loxosceles. Envenomation by Loxosceles spiders can result in dermonecrosis and severe ulceration. Sicarius and Loxosceles spider venoms share a common characteristic, i.e., the presence of Sphingomyelinases D (SMase D). We have previously shown that Loxosceles SMase D is the enzyme responsible for the main pathological effects of the venom. Recently, it was demonstrated that Sicarius species from Africa, like Loxosceles spiders from the Americas, present high venom SMase D activity. However, despite the presence of SMase D like proteins in venoms of several New World Sicarius species, they had reduced or no detectable SMase D activity. In order to contribute to a better understanding about the toxicity of New World Sicarius venoms, the aim of this study was to characterize the toxic properties of male and female venoms from the Brazilian Sicarius ornatus spider and compare these with venoms from Loxosceles species of medical importance in Brazil., Methodology/principal Findings: SDS-PAGE analysis showed variations in the composition of Loxosceles spp. and Sicarius ornatus venoms. Differences in the electrophoretic profiles of male and female venoms were also observed, indicating a possible intraspecific variation in the composition of the venom of Sicarius spider. The major component in all tested venoms had a Mr of 32-35 kDa, which was recognized by antiserum raised against Loxosceles SMases D. Moreover, male and female Sicarius ornatus spiders' venoms were able to hydrolyze sphingomyelin, thus showing an enzymatic activity similar to that determined for Loxosceles venoms. Sicarius ornatus venoms, as well as Loxosceles venoms, were able to render erythrocytes susceptible to lysis by autologous serum and to induce a significant loss of human keratinocyte cell viability; the female Sicarius ornatus venom was more efficient than male., Conclusion: We show here, for the first time, that the Brazilian Sicarius ornatus spider contains active Sphingomyelinase D and is able to cause haemolysis and keratinocyte cell death similar to the South American Loxosceles species, harmful effects that are associated with the presence of active SMases D. These results may suggest that envenomation by this Sicarius spider has the potential to cause similar pathological events as that caused by Loxosceles envenomation. Our results also suggest that, in addition to the interspecific differences, intraspecific variations in the venoms composition may play a role in the toxic potential of the New World Sicarius venoms species.

Acute kidney injury (AKI) can be seen in tropical regions following bites of various venomous animals and insects. Renal failure is seen most commonly following the bite of spiders of the Loxosceles spp. Dermonecrosis, systemic inflammatory response, hemolysis, rhabdomyolysis, and direct venom-related effects are postulated as causes of AKI. We report a documented case of AKI with pigment nephropathy following the bite of a brown spider from a tropical region which is known to have many venomous animals but has no previous reports of AKI following spider bite. Whether this is due to absence of toxic spider species or underreporting needs to be determined.

Phoneutria nigriventer spider bite causes priapism, an effect attributed to the peptide toxins Tx2-5 and Tx2-6 and involving nitric oxide. Tx2-6 (MW = 5287) is known to delay the inactivation of Sodium channels in the same fashion as many other venom toxins. In the present study we evaluated the i.p. dose that induces priapism and the other symptoms in mice. Animals killed by the toxin or crude venom (0.85 mg/kg) were autopsied and a pathological study of brain, lung, kidney, liver and heart was undertaken using standard techniques. The same protocol was employed with animals injected with crude venom. Results showed that priapism is the first sign of intoxication, followed by piloerection, abundant salivation and tremors. An i.p. injection of about 0.3 μg/kg induced only priapism with minimal side-effects. The most remarkable histological finding was a general vascular congestion in all organs studied. Penis showed no necrosis or damage. Lungs showed vascular congestion and alveolar hemorrhage. Heart showed also sub-endothelial hemorrhage. Brain showed only a mild edema and vascular congestion. Results obtained with crude venom closely resemble those of purified toxin. We conclude that Tx2-6 have profound effects on the vascular bed especially in lungs and heart, which may be the cause of death. Interestingly brain tissue was less affected and the observed edema may be attributed to respiratory impairment. To the best of our knowledge this is the first histopathological investigation on this toxin and venom suggesting a possible cause of death., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A case of ulcer of long evolution (more than one year), what happens is presented by different phases and treatment, its origin was caused by a spider bite.

Spider bites are not very common, especially in the Mediterranean area, and those affecting the ocular-palpebral region involving reconstructive surgery are particularly rare. In May 2010, the case of a Caucasian 24-year-old female patient was brought to the attention of the Dermatology Department, University of Cagliari, Italy. The patient reported she woke up feeling an intense pain with itching and that also she had noticed a spider of an unknown species on her bed. The dermatosis had affected the right orbital region, where there was a considerable red and violet erythema and a hard edema, not foldable. When the necrosis appeared the patient was treated at the Plastic Surgery Unit where she underwent a reconstruction of the eyelid with a full thickness skin graft from the retroauricular area. The post-operative course was regular with a perfect in-take of the skin graft. When the patient was discharged she was sent to an Entomological University Centre to identify the spider species and the possible venom which caused the skin lesion. The spider which caused the injury has been a Loxosceles rufescens (Dufour, 1820). Loxoscelism is a necrotic arachnoidism caused by the poisonous bite of spiders belonging to the Loxosceles species. It is very important to identify what sort of lesion it is and to treat it in a combined way in order to choose the proper timing for surgery to avoid damages to the eyelid functioning.

A 69-year-old woman was awakened with redness and swelling of the left upper eyelid a few days before her presentation. She also noticed a dead spider on her bed. Ophthalmic examination revealed severe left periorbital hyperemia, edema and a wide necrotic area on the upper eyelid. Systemic condition of the patient was well. She was hospitalized with the diagnosis of necrotic arachnidism of the left upper eyelid. Systemic corticosteroid and antibiotic treatment was commenced. No surgical intervention was carried out. A week later, whole upper eyelid was covered with a black eschar. This black eschar shrank with time, and it detached completely within 8 weeks and the lesion healed without a disfiguring scar. Meanwhile, the offending spider was identified as Loxosceles rufescens. Although rare, eyelid may be a biting site for Loxosceles spiders and a favorable result may be obtained with conservative management.

Brain areas expressing c-fos messenger RNA were mapped by quantitative in situ hybridization after 1-2 h of intoxication with 10 μg/kg Tx2-6, a toxin obtained from the venom of the spider Phoneutria nigriventer. Relative to saline-treated controls, brains from toxin-treated animals showed pronounced c-fos activation in many brain areas, including the supraoptic nucleus, the paraventricular nucleus of the hypothalamus, the motor nucleus of the vagus, area postrema, paraventricular and paratenial nuclei of the thalamus, locus coeruleus, central amydaloid nucleus and the bed nucleus of the stria terminalis. The paraventricular hypothalamus and the bed nucleus of the stria terminalis have been implicated in erectile function in other studies. A possible role for central NO is considered. Acute stress also activates many brain areas activated by Tx2-6 as well as with NOstimulated Fos transcription. Brain areas that appear to be selectively activated by Tx2-6, include the paratenial and paraventricular thalamic nuclei, the bed nucleus of the stria terminalis and the area postrema and the dorsal motor n. of vagus in the medulla. However, direct injections of different doses of the toxin into the paraventricular hypothalamic n. failed to induce penile erection, arguing against CNS involvement in this particular effect., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The European spider Tegenaria agrestis (Walckenaer) (hobo spider) has been implicated as a spider of medical importance in the Pacific Northwest since its introduction in the late 1980s. Studies have indicated that the hobo spider causes necrotic tissue lesions through hemolytic venom or through the transfer of pathogenic bacteria introduced by its bite. Bacterial infections are often diagnosed as spider bites, in particular the pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA). This study examines three aspects of the potential medical importance of hobo spiders in part of its introduced range, Washington State. First, the bacterial diversity of the spider was surveyed using a polymerase chain reaction-based assay to determine whether the spider carries any pathogenic bacteria. Second, an experiment was conducted to determine the ability of the spiders to transfer MRSA. Third, the venom was evaluated to assess the hemolytic activity. We found 10 genera of ubiquitous bacteria on the exterior surface of the spiders. In addition, none of the spiders exposed to MRSA transferred this pathogen. Finally, the hemolytic venom assay corroborates previous studies that found hobo spider venom was not deleterious to vertebrate red blood cells.

The increase in cases of community-acquired methicillin-resistant Staphylococcus aureus (MRSA), as well as its isolation from the majority of skin and soft tissue abscesses in the emergency department, requires the emergency physician to consider this diagnosis in all skin or soft tissue infections. However, making the diagnosis of MRSA when the wound is actually a cutaneous lesion of a brown recluse spider bite may have untoward consequences. Furthermore, the clinical manifestations of systemic loxoscelism may be misdiagnosed as a systemic staphylococcal infection. We present a patient with systemic loxoscelism who was diagnosed with a systemic infection and received an unnecessary surgical procedure., (Copyright © 2010 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.)