Photocontact allergy to diallyl disulfide.

Although phototoxic reactions to plants are common, photoallergic contact dermatitis to plants and plant products rarely occurs. Our objective was to review the importance of including diallyl disulfide in the evaluation of patients with suspected photosensitivity. Phototests for ultraviolet B, ultraviolet A, and visible light as well as patch tests and photopatch tests for 49 allergens from the New York University Skin and Cancer Unit Photopatch Test Series were performed. Three patients had positive photopatch-test results to diallyl disulfide, which is the allergen in garlic. The authors conclude that although photocontact allergy to diallyl disulfide is rare, this allergen should be included in photopatch-test series.