Brown Recluse Spider Bite?

A 50 year-old landscaper presented for evaluation of a lesion on his back that has been present for one day. While working in heavy brush, he felt something go down his shirt and a couple of hours later experienced a sharp pain in the mid-back. When he got home there was the beginning blister and has expanded over the night.

O/E: 24 hours later, there is a 8 cm in diameter bullae with a 4 mm central area that looks like a puncture wound. The fluid is clear and there’s no evidence of necrosis.

Clinical Images:

25.6.21

7.1.21 He was treated with cold compresses and mupirocin ointment and his lesion resolved uneventfully/

7.2.21

Impression: This fits Brown Recluse Spider bite. No arachnid or insect was found.

There is no proven therapy for BRSB. I suggested cold compresses b.i.d. and mupirocin ointment.

The patient will send me daily pictures. We’ll see how this progresses over the next few days. At present, the lesion is not symptomatic.

Most BRSBs resolve uneventfully.  A small number develop significance necrosis.  The spider is rarely found.

Reference

 1. StatPearls [Internet]: Brown Recluse Spider Toxicity

Ifeanyichukwu A. Anoka; Erika L. Robb; Mari B. Baker.
Last Update: August 10, 2020. This is a useful page.

In the United States, Loxosceles reclusa or brown recluse spiders are found mostly in the south, west, and midwest areas. They are usually in dark areas such as under rocks, in the bark of dead trees, attics, basements, cupboards, drawers, boxes, bedsheets, or similar locations. Dermonecrotic arachnidism is the local tissue injury that results from brown recluse spider envenomation, while loxoscelism describes the systemic syndrome caused by envenomation. This activity reviews the pathophysiology and presentation of the brown recluse spider biiteand highlights the role of the interprofessional team in its management.