Necrotic Loxoscelism of the Scalp.

A 15 month old boy was referred to our department after he and his mother moved to our country. He had been bitten by a brown recluse spider (Loxosceles reclusa) at the age of 7 months, in Brazil. Initially, he presented to the emergency department of his local hospital with rash in the scalp, near the bite. After a few days, he developed systemic disease with multiorgan failure and was admitted on intensive care unit, where he has been treated for 2 months. During this hospital stay he developed skin necrosis of the scalp, right preauricular, mandibular, and neck regions. He also developed right foot ischemia, which resulted in amputation. At the discharge time, he was under topical treatment with silver sulfadiazine, which was maintained until our observation, 8 months after being bitten. The child was successfully treated, and is now stable and awaiting lower limb prosthetic replacement.Loxoscelism (bites by spiders of the genus Loxosceles) is the only proven arachnological cause of dermonecrosis. The brown recluse spider, Loxosceles reclusa, is the best known and can cause necrotic dermatologic injury throw an enzyme, sphingomyelinase D, that has been shown to be cytotoxic to endothelial and red blood cells. Although the majority of persons bitten by a brown recluse spider probably will not seek medical attention, some patients may develop systemic loxoscelism, especially children.