Interstitial granulomatous dermatitis secondary to soy

A healthy 58-year-old woman developed an asymptomatic papular eruption of the neck, cheek, abdomen, arms, and flexures. There was an 8-year history of the lesions, which had erupted when the patient started a strict vegetarian diet. Lesions lasted 3 to 5 days, cleared without scarring, and were associated with burning and increased tearing of the eyes. The biopsy specimen showed an interstitial granulomatous dermatitis without vascular injury, collagen alteration, or mononuclear atypia. The eruption cleared when the patient omitted soy products from her diet. It subsequently recurred with intake of even minimal amounts of soy. Interstitial granulomatous dermatitis is a histologic pattern of inflammation that generates a broad differential diagnosis. No previous reports of interstitial granulomatous dermatitis related to soy products are available in the literature.