28607 – BROWN SPIDER BITE ON THE BREAST: A CASE REPORT

Abstract

Introduction: In the literature, there are few descriptions of breast diseases resulting from Loxosceles (brown spider) bites.
Due to its importance and the severity of this condition, we must always be attentive to situations that may occur in our
environment. Loxosceles, commonly known as the brown spider, is prevalent in the state. Its bite often goes unnoticed, as
it is almost always painless. Identifying this cause is not always straightforward, as there are several similar species that
are not venomous, and the lesion is not pathognomonic from the outset. However, the progression of the condition leads
to a dry and painful lesion with a “target-like” appearance, featuring a hyperemic halo and an ischemic or necrotic center.
In the breast region, necrosis can be extensive due to the high amount of fat, potentially requiring emergency intervention. Case Report: The on-call physician contacted the Poison Control Center (CIT) via telephone to discuss the case: a
64-year-old woman with a history of blisters and hyperemia in the left breast associated with headache, fever, and nausea
for 16 hours. The patient reported finding a spider inside her blouse. After analyzing images of the lesion and the spider at
the CIT, the hypothesis of a Loxosceles bite was raised, and the request for laboratory tests (qualitative urinalysis, complete blood count, serum urea, and serum creatinine), prednisone 40 mg/day for five days, and reevaluation of the lesion
within 24 hours was advised. The patient returned two days later (more than 72 hours after the bite) with normal laboratory results but with a necrotic, painful lesion and hyperemia throughout the left breast. At this point, surgical evaluation
and treatment were indicated to discuss the need for debridement due to the impossibility of administering antivenom
(anti-Loxosceles or anti-arachnid serum), which is only effective within the first 72 hours after the bite. Conclusion: The
authors emphasize the urgency of care and treatment in cases of Loxosceles envenomation.