We report the case of a 27-year-old woman who experienced intense pain in the left scapular region while sleeping. The pain was associated with 2 bleeding stitches, which progressed with local edema and erythema. On the third day, she went to the emergency department, since she had dark urine and the skin lesion had progressed to a violaceous plaque. The laboratory workup revealed anemia and involvement of renal function. She was admitted with a diagnosis of viscerocutaneous loxoscelism and received support therapy, chlorphenamine, cloxacillin, paracetamol, and hydrocortisone. Her condition progressed favorably, and she was discharged after 2 weeks. Local wound care was then applied, and she required an autologous skin graft for closure.

Loxoscelism is a clinical syndrome caused by the bite of spiders of the genus Loxosceles. The syndrome has 2 subtypes: cutaneous loxoscelism, which starts with local erythema and pain that typically progresses to a necrotic ulcer varying in both extension and depth; and viscerocutaneous or systemic loxoscelism, which, in addition to the skin manifestations, is characterized by hemolytic anemia with renal involvement in severe cases. Cutaneous necrosis usually appears sometime around the third day and takes the form of a violaceous livedoid plaque. A dry, necrotic crust with very well-defined borders is visible at 1 week (Figs. 1 a and b). The plaque detaches at 3-5 weeks. One of the keys to diagnosis is the appearance of the marks left on the skin by the spider's chelicerae (fangs) (Fig. 1 c).

Figure 1

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