Garlic‐induced irritant contact dermatitis mimicking nail psoriasis

Dear Editor, Garlic (Allium sativum) is a vegetable of the Alliaceae family and is used as not only a spice but also a folk remedy for various illnesses such as asthma, fever and eruptions. Adverse reactions of naturopathic medicine, such as chemical burns and allergic contact dermatitis resulting from topical treatment with crushed raw garlic, are well documented. We present a case of garlic-induced irritant contact dermatitis caused by peeling of garlic bulbs; this case was clinically similar to a case of nail psoriasis. A 64-year-old woman presented with severe erythematous rashes on all the fingertips of both hands. She had peeled many bulbs of garlic with bare hands 1 month before presentation. Pruritic lesions appeared on the fingertips the next day and progressed to hyperkeratosis and fissuring on the subungual areas. Physical examination revealed crusted and erosive erythematous lesions distributed mainly on the subungual skin of all fingers and distorted nail plates with subungual hyperkeratosis and hemorrhage (Fig. 1a,b). Other regions, including her toes, were intact, and routine laboratory investigations showed no abnormalities. The result of specific immunoglobulin (Ig)E radioallergosorbent test (RAST) for garlic was negative. An incisional biopsy specimen was obtained from the erythematous lesion. Histopathological examination showed a superficial dermal and perivascular infiltrate of lymphocytes with hyperkeratosis and irregular acanthosis; neither spongiform pustules of Kogoj nor band-like inflammatory cell infiltrates were found (Fig. 1c). The patch test result for diallyl disulfide, which is known as the main allergen of garlic responsible for allergic contact dermatitis, was negative. We diagnosed garlic-induced irritant contact dermatitis. She was advised to avoid contact with garlic and was treated