Medicine Specialties Brown Recluse Spider Bite causes skin (death) necrosis within 48-72 hours of the bite

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http://www.emedicine.com/derm/topic598.htm All Sources eMedicine Medscape Drug Reference MEDLINE &ltscriptlanguage="JavaScript1.2" type="text/javascript" charset="ISO-8859-1"src="http://as.emedicine.com/js.ng/Params.richmedia=yes&amptransactionID=39365830&amptile=39365830&ampsite=1&ampaffiliate=2&ampssp=33&ampartid=10020598&ampcg=ckb&amppub=100&amppubs=100&ampct=&amppf=0&ampusp=0&ampst=&ampocc=0&amptid=0&amppos=130"&gt&lt/script&gt&ltscriptlanguage="JavaScript1.2" type="text/javascript" charset="ISO-8859-1"src="http://as.emedicine.com/js.ng/Params.richmedia=yes&amptransactionID=39365830&amptile=39365830&ampsite=1&ampaffiliate=2&ampssp=33&ampartid=10020598&ampcg=ckb&amppub=100&amppubs=100&ampct=&amppf=0&ampusp=0&ampst=&ampocc=0&amptid=0&amppos=160"&gt&lt/script&gtEmail to a colleague You are in: eMedicine Specialties > Dermatology > ENVIRONMENTALBrown Recluse Spider BiteArticle Last Updated: Jan 27, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 11 Authors and EditorsIntroductionClinicalDifferentialsWorkupTreatmentMedicationFollow-upMiscellaneousMultimediaReferencesAuthor: Adam S Stibich, MD, Staff Physician, Department of Dermatology, University of Medicine and Dentistry of New JerseyAdam S Stibich is a member of the following medical societies: American Academy of Dermatology and American Medical AssociationCoauthor(s): Robert A Schwartz, MD, MPH, Professor and Head of Dermatology, Professor of Medicine, Professor of Pediatrics, Professor of Pathology, Professor of Preventive Medicine and Community Health, UMDNJ-New Jersey Medical SchoolEditors: Abby S Van Voorhees, MD, Assistant Professor, Director of Psoriasis Services and Phototherapy Units, Department of Dermatology, University of Pennsylvania School of Medicine, Hospital of the University of Pennsylvania; David F Butler, MD, Professor of Dermatology, Texas A & M University College of Medicine; Director, Division of Dermatology, Scott and White Clinic; Director Dermatology Residency Training Program, Scott and White Clinic; Jeffrey J Miller, MD, Associate Professor, Department of Dermatology, Penn State University, Milton S Hershey Medical Center; Joel M Gelfand, MD, MSCE, Medical Director, Clinical Studies Unit, Assistant Professor, Department of Dermatology, Associate Scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical CenterAuthor and Editor Disclosure Synonyms and related keywords: Loxosceles reclusa, L reclusa, Loxosceles species, spider bite, insect bite, arachnid, arachnid bite, brown recluse spider bite, necrotic arachnidism, necrotic skin lesions, fiddle-back spider, violin spider, systemic loxoscelism, cutaneous loxoscelism, scarlatiniform eruption, morbilliform eruption, urticarial eruption, petechial eruption, hemolysis, hemoglobinuria, thrombocytopenia, disseminated intravascular coagulation, escharINTRODUCTIONSection 2 of 11 Authors and EditorsIntroductionClinicalDifferentialsWorkupTreatmentMedicationFollow-upMiscellaneousMultimediaReferencesBackgroundThe brown recluse spider (Loxosceles reclusa; see Media Files 1-2) is the most prevalent of the Loxosceles species in the United States. All Loxosceles species have the potential to inflict injury to varying degrees. Seen predominantly in the south central part of the United States, the brown recluse spider has been discovered as far north as Illinois and on both coasts. Other members of the Loxosceles species are found throughout the world. Incidents involving the brown recluse spider usually occur in summer months as a consequence of the spider's activity patterns. Bites are rare, even in houses heavily infested with brown recluse spiders; therefore, a diagnosis of brown recluse spider bite is quite unlikely in areas that lack significant populations of Loxosceles spiders.Bites of the recluse spider can cause a condition termed necrotic arachnidism, which begins with the development of an eschar at the bite site, followed by tissue necrosis and skin sloughing. Several groups of spiders have been linked to necrotic skin lesions, but recluse spiders cause most of these lesions. While most recluse bites heal uneventfully, some have a protracted course, with the wound taking months to resolve completely.The recluse commonly is known as the fiddle-back or violin spider because of the distinguishing mark on its cephalothorax. The dull yellow-to-brown coloring of its body further distinguishes the brown recluse. It has a small body relative to its leg span, and 3 pairs of eyes rather than the 4 pairs typical of other spiders. The reclusive mannerism is demonstrated by the locations in which the spiders are encountered. They prefer dark, dry, and undisturbed locations, such as the undersides of logs, boards, and rocks and inside barns and garages. Genital bites have been seen on patients using outhouses. Within homes they are found in attics, closets, and storage areas for bedding, clothing, and furniture. Both the male and female spider can envenomate.PathophysiologyBites and envenomation range from a mild, local, urticarial reaction to full-thickness necrosis.The venom volume is minute, about 4 µL, with 65-100 mcg of protein. The venom contains alkaline phosphatase, 5'ribonucleotide phosphohydrolase, esterase, lipase, hyaluronidase, and, most importantly, sphingomyelinase D2. Sphingomyelinase D2 is responsible for calcium-dependent direct erythrocyte lysis. The degree of hemolysis is individually variable from 20% to more than 95%.Cutaneous necrosis is completely dependent on activation of neutrophils. In rabbit studies, neutrophil infiltration occurs at 6 hours. Neutrophils significantly accumulate at 24-72 hours, preceding skin necrosis and ulceration. This explains why early dapsone initiation may be important to limit necrosis in bites destined for that reaction.FrequencyUnited StatesIn 1994, 1835 brown recluse spider bites were reported to poison control centers nationwide.InternationalThe incidence of bites and envenomation is unknown.Mortality/MorbidityDeath is uncommon. Most patient occurrences documented with fatal envenomation have involved hematologic disorders in children.Systemic loxoscelism is unusual, especially in adults. Cutaneous loxoscelism is not uncommon with bites. Few envenomations, perhaps less than 10%, result in severe skin necrosis or other systemic manifestations.AgeSystemic loxoscelism is most common in children.CLINICALSection 3 of 11 Authors and EditorsIntroductionClinicalDifferentialsWorkupTreatmentMedicationFollow-upMiscellaneousMultimediaReferencesHistoryConstitutional symptoms, including macular, papular, urticarial, petechial, scarlatiniform, or morbilliform eruptionHematologic disorders, such as hemolysis, hemoglobinuria, thrombocytopenia, disseminated intravascular coagulation, methemoglobinemia, and shock (rare but serious complications)FeverHeadacheMalaiseArthralgia and rhabdomyolysisNauseaVomitingRenal failurePhysicalThe bite typically is painless, and findings of a central papule and associated erythema may not be seen for 6-12 hours. Few envenomations, perhaps less than 10%, result in severe skin necrosis or other systemic manifestations.Wounds destined for necrosis usually show signs of progression within 48-72 hours of the bite.Central blistering with a surrounding gray-to-purple discoloration of the skin may be seen at the bite site.A surrounding ring of blanched skin is itself surrounded by a large area of asymmetric erythema leading to the typical "red, white, and blue" sign of a brown recluse bite. At this stage of evolution, these bites may be associated with significant pain related to incipient necrosis of skin and subcutaneous tissues. The resultant eschar and ulceration may take months to resolve.Note that patients who are destined for a severe reaction usually develop key signs within 6-12 hours, such as bullae formation, cyanosis, and hyperesthesia.Areas with increased adipose tissue, such as the thighs, buttocks, and abdomen, are more likely to undergo severe necrosis than bites occurring at other sites.