Atypical diaper dermatitis: contact allergy to mercapto compounds.

We present a case of allergic contact dermatitis in an 18-month-old boy caused by type-IV allergy to mercapto mix and mercaptobenzothiazole as components of the elastic border of diapers. Allergic contact dermatitis should be included in the differential diagnosis of diaper dermatitis, especially in difficult-to-treat cases or atypical clinical presentation.