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Case Reports

Abstract

Alpha-gal syndrome (AGS) is a delayed hypersensitivity to alpha-gal, a carbohydrate allergen found in red meat and other mammalian products, often sensitized by tick bites. Urticaria-like cutaneous symptoms present hours after exposure, along with abdominal discomfort, and possibly anaphylaxis. The histopathologic findings of persistent AGS eruption have never been reported in the literature. Herein, we report the case of a 49-year-old woman with a past medical history of asthma, renal artery stenosis, and AGS who presented with a 4-year history of intermittent, pruritic hives. Physical examination revealed persistent erythematous, edematous papules and plaques on the face, neck, legs, and trunk. A punch biopsy from the right proximal posterior thigh revealed mounds of parakeratosis with spongiosis and dermal eosinophils, endothelial swelling with neutrophilic migration. While the dermal histopathologic findings can be consistent with urticaria with partial features of urticarial vasculitis, the epidermal changes cannot be explained by urticaria alone and are reminiscent of pityriasis rosea. Although AGS is generally believed to be IgE-mediated, the histopathologic features in our case suggest potential additional pathogenic mechanisms in persistent AGS skin eruptions. To our best knowledge, this is the first description of cutaneous histopathology of AGS in the literature. Our case contributes to the growing knowledge of AGS and suggests that AGS may present with novel histopathologic features that extend beyond urticaria.