Both biopsy specimens showed similar microscopic changes, consisting mainly of superficial and deep perivascular lymphocytic infiltrates, with only occasional eosinophils and neutrophils. There was no epidermal change. Extravasated erythrocytes were found perivascularly, but there was no evidence of vasculitis. All stains were negative for microorganisms and foreign bodies, and no polarizable material was identified.
Treatment with topical 0.05% diflorasone diacetate ointment and oral hydroxyzine (25 mg every 4 hours) seemed to lessen the eruption, and within 10 days it had completely resolved. Six weeks later, serum enzyme-linked immunosorbent assay revealed IgG at a titer of 1:450 against Linuche unguiculata, the thimble jellyfish.
Pruritic Urticarial Papules of the Thighs and Groin. Arch Dermatol. 2000;136(11):1409-1414. doi: