Spiders and Spider Bites

Venomous spiders of Albania –does an increase of temperature influence the toxicity of spider venom?

Black widow spiders (Latrodectus sp.) are distributed worldwide, and in Albania the L. tredecimguttatus Rossi, 1790 has been the dominant spider. Other medically important spiders in Albania include the brown recluse with symptoms known as loxoscelism, the false black widow and the egg sac spiders; the last two inducing similar symptoms to a wasp sting. Methods: The data analyzed is from a decade-long study of 125 patients hospitalized in the regional hospital of Fier County, in the Western Lowland of Albania from May 2009 and to October 2018. Objective: Although the venom is rarely fatal, the recent spider bites raise questions about the influence of higher air temperatures on their possibly increased toxicity. Results: Significantly the severity of the α-latrotoxin rises during the summer, when human–spider contact frequency is higher and when the black widow spiders have an increased motivation to protect their egg sacs. Conclusion: This study revealed an increased severity of the black widow bites with respect to patient health, shown via all the severe systemic symptoms, during those months with higher temperatures.

•

The spider bites revealed a higher venom severity during summer, when there was a higher human-spider contact frequency.

•

The longer recovery times are probably related to the quantity and toxicity of the spider venom á-latrotoxin.

•

Extreme environmental conditions increase the spider motivation to protect the egg sac and self-protect.

•

Higher environmental temperatures may thus lead to higher black widow venom toxicity during the hot summer months.

Systemic loxoscelism induced warm autoimmune hemolytic anemia: clinical series and review

OBJECTIVES

Describe the development of warm autoimmune hemolytic anemia warm (AIHA) secondary to a brown recluse spider (Loxosceles reclusa) bite is known as systemic loxoscelism; and review epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

METHODS

Cases series of two cases of warm AIHA due to systemic loxoscelism and a review of the current literature: epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

RESULTS

Presented here are two cases of warm AIHA due to systemic loxoscelism. Each patient was generally healthy appearing and presented with symptomatic anemia in the setting of brown recluse spider bites. Both patients were eventually found to have warm AIHA. Upon recognition of the diagnosis, the patients were started on corticosteroids and aggressive intravenous fluid hydration. In addition, they received transfusions of packed red blood cells. Their clinical courses improved, and they recovered to eventually be discharged home.

CONCLUSION

Envenomation by a brown recluse spider, Loxosceles reclusa, can result in systemic loxoscelism which can cause warm AIHA. The diagnosis of warm AIHA is confirmed by the direct antiglobulin/Coomb's test. Warm AIHA can be a life-threatening disease process. Hemodynamic support with intravenous fluids and RBC transfusion is the initial step in the management of these patients. Corticosteroids are the mainstay of current management. Second line treatments include rituximab. Rarely patients require splenectomy for refractory disease. Corticosteroids should be tapered over a three-month period.

Unintended importation of tropical jumping spiders (Salticidae) into a laboratory monkey colony via banana supply

This report describes a case of unintended importation of tropical baby jumping spiders to a laboratory monkey colony. The spiders were detected in a cocoon attached to a banana for monkey consumption. In identifying the family of spiders as jumping spiders (Salticidae), it turned out that these spiders would not have been venomous to humans and they most likely would not have had the potential to establish a new spider colony in the facility.

Clinical aspects, diagnosis and management of Loxosceles spider envenomation: literature and case review

The genus Loxosceles comprises 140 species widely distributed around the world. These spiders are nocturnal, sedentary and remarkably nonaggressive, although they cause accidents in humans with wide degrees of severity, generating signs and symptoms that define the clinical condition known as loxoscelism. Its local signs and symptoms were first reported in 1872, and over the years, a large medical literature has been accumulated; unfortunately, it is not always trustworthy. Assessing the reliability of such information, we reviewed 120 case reports of loxoscelism published in 84 articles over the past 20 years. This search allowed us to gather information on the clinical aspects, diagnosis and treatment of loxoscelism, showing that the severity of these accidents has multiple degrees and that it is influenced by many factors. Thus, coupled with epidemiological and species occurrence information, this study can be a useful tool for the clinical practice of loxoscelism. It may support and provide a multidisciplinary view that should be taken into consideration when establishing the therapeutic approach in cases of Loxosceles envenomation.

Toxicity of two North American Loxosceles (brown recluse spiders) venoms and their neutralization by antivenoms

The toxic, biochemical, and immunological characteristics of L. boneti and L. reclusa venoms and its neutralization by anti-L. boneti and anti-L. reclusa antivenoms were studied. The electrophoretic profile showed very similar patterns and the toxic activities were very close. Immunological studies showed cross-reactivity among L. boneti and L. reclusa venoms, with L. boneti and L. reclusa experimental antivenoms, and anti-L. gaucho and anti-L. laeta antivenoms. The venom of L. laeta showed low immunological reactivity with the North American Loxosceles antivenoms. Experimental anti-North American Loxosceles antivenoms protected mice of the systemic toxicity and were able to prevent necrosis in rabbit skin after the injection of the venom. Both antivenoms displayed cross neutralization. The results showed that both Loxosceles venoms have very close toxic, biochemical, and immunological characteristics, and that either monospecific antivenoms or an antivenom raised with L. boneti and L. reclusa venoms as immunogens could be useful for treating bites by North American Loxosceles spiders.

Negative pressure wound therapy: treating a venomous insect bite

Reports of spider bites appear throughout North America. Bites associated with the brown recluse spider (Loxosceles recluse) cause serious medical complications because the venom of this spider contains a powerful necrotising agent with the potential to cause severe cutaneous necrosis. Although not much is known regarding the application of negative pressure wound therapy (NPWT) to spider bites, this therapy has considerable literature support for its efficacy, cost-effectiveness and ease of use in chronic, difficult-to-heal wounds. A case study using NPWT to successfully treat a non healing upper arm wound presumed due to a venomous spider bite is presented here. The patient was successfully treated with a new, less costly NPWT product called the Versatile 1 and a new combination drain plus dressing called the Miller DermiVex drain, both manufactured by Blue Sky Medical (Carlsbad, CA).

Epidemiology of the brown recluse spider bite

PURPOSE

The purpose of this article was to provide a comprehensive epidemiological and clinical description of the brown recluse spider bite.

DATA SOURCES

Review of evidenced-based scientific literature and practice guidelines. A specific descriptive case study is interwoven through the article to tie in the clinical presenting figure associated with this bite.

CONCLUSIONS

The brown recluse lives in a circumscribed area of the United States (the south central Midwest) with a few less common recluse species living in the more sparsely populated southwest United States. In these areas, where spider populations may be dense, recluse spiders may be a cause of significant morbidity.

IMPLICATIONS FOR PRACTICE

Most spider bites are asymptomatic but what makes this bite so devastating is the toxin injected by the brown recluse spider, which can cause considerable systemic symptoms as well as necrotic skin ulcers (necrotic arachnidism). The article presents process for diagnosis and stresses the importance of identifying the spider if at all possible.

Epidemiological and clinical manifestations of patients hospitalized with brown recluse spider bite

BACKGROUND

Necrotic arachnidism represents a common health problem and standard treatments are usually safe and effective.

OBJECTIVE

The aim of this study was to review documented Loxosceles species spider envenomations and identify the natural history of affected patients.

METHODS

A retrospective single-centre study included 52 patients with necrotic arachnidism hospitalized in the dermatology department between 1997 and 2004. We examined the relationship between the epidemiological, clinical and laboratory parameters and degree of lesion severity, length of hospitalization and time to complete healing.

RESULTS

The bites occurred predominantly in rural areas, 67% between April and August. Only 35% of the patients sought medical care within 24 h post bite. Most bites were of the extremities (67%). Time to complete healing ranged from 14 days to more than 8 weeks (mean, 4.8 weeks). A marked relationship was found between age, comorbidities, lesion severity and time to complete healing (P < 0.01). Duration of hospitalization was significantly longer in patients with severe thigh lesions (P < 0.02).

CONCLUSIONS

Loxosceles species spider bites frequently induce necrotic, slowly healing ulcers on the fatty areas of the body. Early, appropriate systemic therapy may provide clinical benefit.

Local cutaneous arachnidism: a report of three cases and their management

Bites from Loxosceles spiders can cause few symptoms to gangrenous skin necrosis or even death. To date, the treatment of the violin spider bite is largely unsatisfactory. Although no specific therapy exists, it has been suggested that heparin, steroids, dapsone, experimental antivenin and/or surgical excision may be beneficial. Three rare cases of suspected spider bite and their surgical treatment are reported. On the basis of geographical area, anamnesis and clinical symptoms, we suppose Loxoceles rufescens responsible for these bites.

Arachnids submitted as suspected brown recluse spiders (Araneae: Sicariidae): Loxosceles spiders are virtually restricted to their known distributions but are perceived to exist throughout the United States

An Internet offer was made to identify any spider in the United States perceived to be a brown recluse spider, Loxosceles reclusa Gertsch & Mulaik (Sicariidae). In total, 1,773 arachnids from 49 states represented three orders (Araneae, Solifugae, and Opiliones) and the identifiable spiders (Araneae) consisted of 38 families, 88 genera, and 158 recognizable species. Participants from states at least half within the known brown recluse distribution submitted Loxosceles spiders 32- 89% of the time, except Louisiana and Mississippi with no submissions. From 25 of 29 states completely or almost completely outside of the range of Loxosceles spiders, no recluse spiders were submitted. Only two discoveries of brown recluses and two of the worldwide tramp species Loxosceles rufescens (Dufour) were submitted from nonendemic Loxosceles areas. States on distribution margins of brown recluse or other native Loxosceles spiders were intermediate in their Loxosceles submissions. This study showed that 1) the general public perceives brown recluses to occur over wide-ranging areas of the United States; and 2) brown recluses are frequently submitted from endemic states and almost never from nonendemic states, and therefore are virtually limited to their known distributions. This study corroborates opinions that diagnosis of brown recluse spider bites is best restricted to areas historically supporting proven, widespread populations of Loxosceles spiders.

Idiopathic necrotizing dermatitis: current management

OBJECTIVES

To identify and demonstrate necrotizing dermatitis in infancy; an uncommon, puzzling syndrome, in which anecdotal reporting and personal experience indicates that one third of cases may require skin grafting. Much informed discussion about the pathogenesis of this distressing syndrome centres on the role of spider envenomation; and in particular on the speculative role of the Australian White-tailed spider, Lampona cylindrata.

METHODS

We present here six cases of necrotizing dermatitis treated surgically at the Royal Children's Hospital and Mater Children's Hospital in Brisbane over the period from 1991 to 1999. Clinical history, surgical details and pathological investigations were reviewed in each case. Microbiological investigation of necrotic ulcers included standard aerobic and anaerobic culture.

RESULT

Nocardia and Staphylococcus were cultured in two cases, but no positive bites were witnessed and no spiders were identified by either the children or their parents. All cases were treated with silver sulphadiazine creme. Two of the infants required general anaesthesia, excision debridement and split skin grafting. The White-tailed spider, Lampona cylindrata, does not occur in Queensland, but Lampona murina does; neither species has necrotizing components in its venom. Circumstantial evidence is consistent with this syndrome being due to invertebrate envenomation, possibly following arachnid bites.

CONCLUSION

In our experience there is insufficient evidence to impute a specific genus as the cause, at this stage of scientific knowledge. If the offending creature is a spider, we calculate that the syndrome of necrotizing dermatitis occurs in less than 1 in 5000 spider bites.

Loxoscelism: Old obstacles, new directions

Loxosceles spiders have a worldwide distribution and are considered one of the most medically important groups of spiders. Envenomation (loxoscelism) can result in dermonecrosis and, less commonly, a systemic illness that can be fatal. The mechanism of venom action is multifactorial and incompletely understood. The characteristic dermonecrotic lesion results from the direct effects of the venom on the cellular and basal membrane components, as well as the extracellular matrix. The initial interaction between the venom and tissues causes complement activation, migration of polymorphic neutrophils, liberation of proteolytic enzymes, cytokine and chemokine release, platelet aggregation, and blood flow alterations that result in edema and ischemia, with development of necrosis. There is no definitive treatment for loxoscelism. However, animal model studies suggest the potential value of specific antivenom to decrease lesion size and limit systemic illness even when such administration is delayed.

Brown Recluse Spider Bites to the Head: Three Cases and a Review

Consequences of envenomation from the bite of a brown recluse spider (Toxosceles reclusa) range from mild itching to death. The bite of this spider causes the most severe form of arthropod-induced tissue necrosis. These bites pose several challenges to the clinician in that diagnosis can be difficult, systemic manifestations can occur, and healing can be resistant to conventional measures. Bites to the head and neck—particularly the face—are uncommon, and they have not been widely reported in the otolaryngology literature. As experts in facial soft tissue, otolaryngologists and facial plastic surgeons should be able to recognize and treat these lesions. Because no laboratory test is available to identify the cause of symptoms in these cases, the diagnosis is made clinically. Early intervention can make a significant difference in cosmetic outcome, so a high index of suspicion is warranted. Local wound care includes rest, ice, compression, and elevation of the affected part of the body. Drug therapy with dapsone may limit the severity of the bite and prevent complications. Because some bites cause systemic loxoscelism, clinicians should be familiar with its manifestations. When necrosis occurs despite adequate medical treatment, reconstructive procedures should be delayed until healing is complete. We report 3 cases of brown recluse spider bites to the head. These cases illustrate the broad spectrum of the disease course, and they highlight the therapeutic challenges that these lesions pose.

Arthropods in dermatology

Arthropods are important in medicine for a multitude of reasons. Their bites and stings may induce allergic reactions, ranging from annoying to life-threatening. Many arthropod products are also capable of inciting allergic responses in sensitized persons. In recent years, bites and stings have gained greater attention owing to increased concern about disease transmission. A common hypersensitivity response to arthropod bites, stings, and products is papular urticaria. This eruption occurs primarily in children, who eventually "outgrow" this disease, probably through desensitization after multiple arthropod exposures. Papular urticaria is most often caused by fleas or bedbugs, but virtually any arthropod is capable of inducing such a reaction. Two arthropod classes of medical importance are the Arachnida (spiders, scorpions, ticks, and mites) and the Insecta (lice, fleas, bedbugs, flies, bees, and ants). Animals in these two classes are probably responsible for more morbidity and mortality worldwide than are any other group of venomous creatures. In general, the diagnosis of arthropod bites and stings is dependent on maintenance of a high index of suspicion and familiarity with the arthropod fauna not only in one's region of practice, but also in the travel regions of one's patients. Learning objective At the completion of this learning activity, participants should be familiar with the clinical manifestations caused by a variety of arthropods as well as the treatment and possible sequelae of arthropod attacks.

The critical role of pathology in the investigation of bioterrorism-related cutaneous anthrax

Cutaneous anthrax is a rare zoonotic disease in the United States. The clinical diagnosis traditionally has been established by conventional microbiological methods, such as culture and gram staining. However, these methods often yield negative results when patients have received antibiotics. During the bioterrorism event of 2001, we applied two novel immunohistochemical assays that can detect Bacillus anthracis antigens in skin biopsy samples even after prolonged antibiotic treatment. These assays provided a highly sensitive and specific method for the diagnosis of cutaneous anthrax, and were critical in the early and rapid diagnosis of 8 of 11 cases of cutaneous anthrax during the outbreak investigation. Skin biopsies were obtained from 10 of these 11 cases, and histopathological findings included various degrees of ulceration, hemorrhage, edema, coagulative necrosis, perivascular inflammation, and vasculitis. Serology was also an important investigation tool, but the results required several weeks because of the need to test paired serum specimens. Other tests, including culture, special stains, and polymerase chain reaction assay, were less valuable in the diagnosis and epidemiological investigation of these cutaneous anthrax cases. This report underscores the critical role of pathology in investigating potential bioterrorism events and in guiding epidemiological studies, a role that was clearly demonstrated in 2001 when B. anthracis spores were intentionally released through the United States postal system.

Sudden unexplained hemolysis occurring in an infant due to presumed Loxosceles envenomation

We report the case of a 3-week-old infant referred for evaluation of sudden onset jaundice and unexplained hemolysis. After an exhaustive workup, the most likely etiology was found to be envenomation by a brown recluse spider, Loxosceles reclusa. This case underscores the fact that severe loxoscelism may occur in the absence of the classically described necrotic cutaneous lesion, and represents one of the youngest presumed cases of loxoscelism. We present the case to illustrate the importance of considering loxoscelism in the differential diagnosis of sudden massive hemolysis in children, particularly in endemic areas of the midwestern and southern United States.

Papular urticaria and things that bite in the night

Whether we are hiking in the back country or playing in our backyard, we run the risk of exposure to offending arthropods. Papular urticaria is a very common hypersensitivity reaction to the bites, stings, and contact with critters such as mites, ticks, spiders, fleas, mosquitoes, midges, flies, and even caterpillars. Children seem to be at greatest risk, although adults are also vulnerable. The classic presentation of papular urticaria includes recurrent pruritic papules or vesicles and varying degrees of local edema. Severity is often related to the host response to the salivary or contactant proteins. Our understanding of the immune mechanism continues to improve; however, our approach to therapy has remained essentially unchanged. Although this review admittedly reaches beyond papular urticaria, it is with the intention of improving the reader's recognition of the offending arthropods, the characteristics of reactions, and the current therapeutic approaches.

The brown spider Loxosceles laeta: source of the remedy Tarentula cubensis?

The homeopathic remedy Tarentula cubensis (Cuban tarantula), used in homeopathy to treat abscesses with burning pains, gangrene, septicaemia, toxaemia, has been grouped by homeopathic authorities with either the mygalomorph or wolf spiders. The original specimen used for preparation of the mother tincture was decomposed, leaving the spider's exact identity in doubt. Investigation of the toxicological and clinical literature, compared with homeopathic materia medica, reveals the brown spider, Loxosceles laeta, indigenous to South America but present also in Mid- and North America, as a more likely source. Venoms of spiders of the genus Loxosceles cause severe necrotic arachnidism, as well as, in some cases, a life-threatening systemic reaction marked by renal failure, disseminated intravascular coagulation, thrombocytopeania, coma and convulsions.

Clinical and epidemiological features of definitive and presumed loxoscelism in São Paulo, Brazil

A retrospective study analysed 359 proven or presume cases of loxoscelism seen at the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil, between 1985 and 1996. The spider was identified in 14%. The bites occurred predominantly in the urban areas (73%) between September and February. Patients > 14 years were commonest inflicted (92%) and 41% were bitten while getting dressed. Only 11% sought medical care within the first 12 hours post bite. Cutaneous loxoscelism was the commonest form presenting (96%); commonest manifestations were: pain (76%), erythema (72%), edema with enduration (66%), ecchymosis (39%). Skin necrosis occurred in 53% of patients, most frequently seen on trunk, thigh and upper arm, and when patients seek medical care more than 72 hours after bite. Local infection was detected in 12 patients (3%). Hemolysis was confirmed in 4 cases (1.1%). Generalised cutaneous rash, fever and headache were also observed in 48% of the total of patients. None of them had acute renal failure or died. Treatment usually involved antivenom administration (66%), being associated with corticosteroids (47%) or dapsone (30%). Presumptive diagnosis of loxoscelism may be established based on clinical and epidemiological findings. Further investigations are required to prove the value of antivenom and other treatment schedules.

Dapsone and sulfones in dermatology: overview and update

In their 60-year history, dapsone and the sulfones have been used as both antibacterial and anti-inflammatory agents. Dapsone has been used successfully to treat a range of dermatologic disorders, most successfully those characterized by abnormal neutrophil and eosinophil accumulation. This article reviews and updates the chemistry, pharmacokinetics, clinical application, mechanism of action, adverse effects, and drug interactions of dapsone and the sulfones in dermatology.

Nineteen documented cases of Loxosceles reclusa envenomation

OBJECTIVE

Our purpose was to review documented Loxosceles reclusa (brown recluse spider) envenomations and to describe the natural history.

METHODS

This article is a retrospective review of 19 documented cases seen in a university dermatology clinic. The study included the cases of 11 female and 8 male patients between the ages of 15 and 54 years with documented cases of brown recluse spider bite between 1987 and 1993. Rest, ice compresses, elevation, and prophylactic antibiotics were used in all cases. Fourteen patients received dapsone and 11 received nonsteroidal anti-inflammatory drugs. Two patients were hospitalized. A 3-point scale of cutaneous lesion severity was developed. Analysis of the association between maximum lesion severity (mild, moderate, severe) and time to complete healing or final evaluation was statistically significant (P < .001).

RESULTS

All patients presented with localized erythema. Most bites were on the extremities (18/19; 95%). The most common presenting symptom was pain at the bite site (10/19; 53%). Eleven patients (58%) had skin necrosis; 32% of them had areas of necrosis larger than 1 cm(2). Time to healing ranged from 5 days to more than 17 weeks (mean, 5.6 weeks). Average time to healing for grade 3 (severe) lesions was 74 days, for grade 2 (moderate) lesions 22 days, and for grade 1 (mild) lesions 8 days (in patients seen more than once).

CONCLUSIONS

Brown recluse spider bites frequently induce necrotic, slowly healing lesions. Maximum lesion severity is a predictor of time to complete healing.

Necrotic arachnidism

Necrotic arachnidism is the potential cutaneous reaction to spider bite venom. In the United States, members of 7 spider families may be responsible for envenomation sufficiently severe to warrant treatment. Characteristics of several spiders, in particular Loxosceles spiders, whose bite is toxic to humans are described, and diagnostic standards, preventive measures, and treatment options are reviewed. (J Am Acad Dermatol 2001;44:561-73.)

LEARNING OBJECTIVE

After the completion of this learning activity, participants should be familiar with the characteristics of several different spider families endemic to the United States. Furthermore, this learning activity should aid in the prevention and diagnosis of spider bites as well as in the classification and treatment of specific bites.

A century of the synthesis of dapsone: its anti-infective capacity now and then

BACKGROUND

Although dapsone was first synthesized in 1908, a quarter of a century was to pass before it was used in the treatment of bacterial infections. Dapsone was, however, too toxic for humans (because of the excess dosage which was administered at that time) and was thus considered to be of no value in the treatment of common bacterial infections. Since the early 1950s, dapsone has been recognized as being uniquely effective against a number of noninfectious, inflammatory diseases and, today, this is its main indication. Thus, the reason why dapsone was first introduced into medicine, namely the treatment of bacterial infections, has been set aside and its main current applications are the treatment of noninfectious, inflammatory, autoimmune, and bullous diseases.

OBJECTIVE

To study the anti-infective capacity of dapsone against common bacterial infections. As many patients who receive dapsone for the treatment of noninfectious, inflammatory diseases have a concomitant bacterial infection or a superinfection of their skin disease, we thought that, if dapsone proved to be effective against common bacterial infections, it may obviate the need for an additional antimicrobial drug in these patients.

METHODS

Three bacterial ATCC> strains (Streptococcus pyogenes, Staphylococcus aureus, and Escherichia coli) were tested by a macrodilution minimal inhibitory concentration (MIC) test for dapsone. Dapsone concentrations were between 0.06 and 1125 microg/mL.

RESULTS

Even the highest concentration of dapsone of 1125 microg/mL did not inhibit bacterial growth.

CONCLUSIONS

Our results indicate that dapsone has no antibacterial effects whatsoever. Even at very high concentrations, it does not suppress the growth of most susceptible strains of bacteria. The story of dapsone (i.e. the long time that elapsed between its synthesis to its use for the chemotherapy of infectious diseases) will not repeat itself this time.

Envenomations

Envenomations are uncommon, challenging causes of critical care admissions. This article describes the diagnosis and treatment of envenomations that cause the most critical care admissions in the United States. Most are caused by the following animals: rattlesnakes, copperheads, cottonmouths, coral snakes, brown recluse spiders, and bark scorpions.

Managing arthropod bites and stings

Most arthropod bites and stings cause limited swelling, itching, pain, and redness and can be managed by ice application and tetanus prophylaxis as necessary. Stings by bees, wasps, and stinging ants can cause anaphylaxis that may require treatment with epinephrine and antihistamines and respiratory and cardiac maintenance measures. Widow spider bite management is controversial, but interventions for systemic reactions include calcium gluconate, methocarbamol, diazepam, narcotics, and antivenom. Victims of brown spider bites may need hospitalization if lesions enlarge rapidly or there are signs of systemic poisoning. Those stung by a bark scorpion may require oxygen, an intravenous line, pulse oximetry, and cardiac monitoring.

Clinical presentation and outcome of brown recluse spider bite

STUDY OBJECTIVE

To examine the clinical presentation and outcome of patients treated in the ED or toxicology clinic for suspected brown recluse spider bites.

METHODS

We assembled a retrospective case of patients at a southeastern US university hospital. Our study group comprised 111 patients with suspected brown recluse spider bites treated during a 30-month period. Our main outcome measures were the need for skin grafting and the development of other complications.

RESULTS

The mean age of our subjects was 34 +/- 17 years. Thirteen patients (12%) brought the spider to the hospital, 22 (20%) saw a spider at the time of the bite, and an exclusively clinical diagnosis was made in the remaining 76 (68%). Most wounds (59%) involved the leg. At the time of presentation, 81% had central discoloration and 37% necrosis. Sixteen patients (14%) were systemically ill, and 6 (5%) were admitted to the hospital. Most (86%) were treated with antibiotics. Dapsone was infrequently used (9%) and had usually been prescribed before the patient's presentation to our ED. Only three patients (3%; 95% confidence interval, 1% to 8%) required grafting. Mild hemolytic anemia developed in one patient, and another had mild hemolysis and a mild coagulopathy; neither patient was taking dapsone. No deaths or serious complications occurred in our study group.

CONCLUSION

In our series, long-term outcome after brown recluse spider bite was good. Serious complications were rare, as was the need for skin grafting. Because the vast majority of bites heal with supportive care alone, aggressive medical therapy does not appear warranted.

Upper airway obstruction caused by brown recluse spider envenomization of the neck

A 7-year-old boy presented to the emergency department with progressive cervical soft tissue swelling and airway compromise due to envenomization by a brown recluse spider. This life-threatening complication is an extremely unusual presentation of brown recluse spider envenomization. Previous published reports have centered on the disfiguring localized tissue necrosis or life-threatening systemic reactions that occur secondary to the spider's venom.

Comparison of hyperbaric oxygen and dapsone therapy for loxosceles envenomation

OBJECTIVE

To determine whether hyperbaric O2 (HBO), dapsone, or HBO plus dapsone affects lesion size in a swine model of Loxosceles envenomation.

METHODS

In a randomized controlled animal laboratory experiment, 32 piglets were assigned to 1 of 4 equal groups. Each piglet received 15 microliters, of purified venom intradermally on day zero. Group 1 received no treatment; group 2 received HBO at 2 atm for 2 hours on days 1-3; group 3 received 50 mg of dapsone orally on days 1-3; and group 4 received dapsone 50 mg orally and HBO at 2 atm for 2 hours on days 1-3. On days 1-7, 14, and 21, an investigator blinded to the treatment groups measured necrosis and induration. Mean necrosis and induration rates were compared using analysis of variance for repeated measures.

RESULTS

Comparing groups on any day, no significant difference was noted in necrosis, induration, reduction in necrosis from day 1, or rate of change in lesion size from days 1-7. A difference was seen in the reduction of induration between all 3 treatment groups and the control group on days 7 and 14 only. The sample size permitted a power of 0.8 to detect a 12-mm mean change in lesion size.

CONCLUSION

Compared with the control, neither dapsone, HBO, nor the combination of dapsone and HBO reduced necrosis from Loxosceles envenomation on days 3-21. An increase was seen in the rate of reduction in induration between all 3 treatment groups and the control group on days 7-21. However, the magnitude of this effect was clinically insignificant. In this animal model, treatment with either dapsone or HBO or a combination offers little clinical benefit in Loxosceles envenomation.

Dapsone or electric shock therapy of brown recluse spider envenomation?

STUDY OBJECTIVES

We tested the null hypothesis that no outcome differences exist among the treatment groups of animals with brown recluse spider envenomations.

STUDY DESIGN

A prospective, placebo-controlled, experimental trial. Hartley guinea pigs were randomized into the following treatment groups: dapsone, Parali/azer stun gun, Guardian stun gun, and control.

INTERVENTIONS

Brown recluse spider skin lesions were induced with intradermal injections of 30 micrograms spider venom and were treated beginning 16 hours after inoculation. Shock regimens consisted of four cross shocks of 1-second duration on anesthetized animals. Oral dapsone treatment was 0.7 mg/kg twice daily for 3 days. Lesion areas were measured daily for 3 days.

RESULTS

The dapsone therapy group demonstrated significantly less induration and necrosis (P < .05) than that shown by the other three groups 72 hours after envenomation.

CONCLUSION

Dapsone therapy is more effective than either electric shock or no therapy for brown recluse spider envenomation in the guinea pig model.

Hemolytic anemia following a presumptive brown recluse spider bite

This case report describes a systemic reaction occurring in a 12-year-old female following presumed envenomation by a brown recluse spider (Loxosceles reclusa). The systemic reaction included self-limited hemolysis necessitating blood transfusion. The clinical course and management are described and compared with those of previously reported cases of systemic loxoscelism.

Skin problems in returning travelers

A new skin lesion in a returning traveler often poses a difficult diagnostic problem for the clinician whose knowledge of geographic medicine is limited. To reach a diagnosis the physician has to consider the location and style of travel, exposure to pathogens, length of stay, epidemiology, incubation period, and clinical presentation of dermatologic diseases in the countries visited. As with any dermatologic problem, the appearance of the presenting lesion should help to establish the differential diagnosis. This article is a guide to the diagnosis and investigation of skin lesions in returning travelers; it is not intended as a comprehensive review of tropical dermatology.