Occupational airborne allergic contact dermatitis from potassium metabisulfite

Sulfites are heterogeneous compounds that are widely used as preservatives and antioxidants in foods, beverages, drugs, and cosmetics, as fixatives in the photographic industry, and as acidifying agents in tanning of leather. They mainly cause immunoglobulin E-mediated disorders (6), but contact dermatitis from sodium metabisulfite is reported. A 37-year-old non-atopic male agricultural worker presented with a 5-year history of itchy erythema, swelling and scaling of his face, and itchy erythematopapular scaly dermatitis of the forearms. The lesions occurred after the grape harvest. During his job, the patient added potassium metabisulfite to prevent yeast and bacteria proliferation and wine oxidation. When away from work, the dermatitis spontaneously healed in 10 days. Patch testing showed positive reactions to potassium metabisulfite and sodium metabisulfite. Moreover, positive delayed eczematous reactions to prick and intradermal tests with potassium metabisulfite and sodium metabisulfite were observed. We emphasize the airborne exposure of our patient, never reported in relation to sulfite sensitivity. The positive delayed reactions to skin tests with sodium metabisulfite were not considered a relevant cross-reaction.