Severe immediate hypersensitivity and allergic contact dermatitis caused by hair dyes

A 43-year-old female experienced dermatitis of the scalp and neck after each hair colouring, which was carried out every 6 weeks. She had no medical history and had never had any temporary black henna tattoo. In August 2010, the application of hair dye provoked an immediate pruritus of the scalp, with a malaise that lasted for 15 min. During the following hair dye procedure, a severe reaction occurred, with generalized pruritus and erythema, dyspnoea, vomiting, and hypotonia. The symptoms disappeared over a 2-hr period at home. The usual contact dermatitis appeared thereafter, and lasted for 8 days. The skin tests were performed under strict medical monitoring, with the consent of the patient, who had an intravenous access. The open tests were first applied for 30 seconds and read at 20 min. The results were doubtful (localized pruritus) for the hair dye (mixture of colouring cream with an oxidant, 1:1) and negative for the colouring cream and the developer tested separately. Then, open tests were applied and read at 20 min. The results were positive (strong localized urticarial reaction) for the hair