Cocamidopropyl betaine: the significance of positive patch test results in twelve patients.

Cocamidopropyl betaine is a surfactant coming into wide use in shampoos and other cleansing products. Recent reports have implicated it as a potential allergen, although it is less irritating than other surfactants such as sodium lauryl sulfate. Twelve positive patch test results were seen over a period of fifteen months of testing in selected patients. Of these, seven results were thought to be relevant. All seven patients with relevant reactions and four of the five with uncertain relevance had dermatitis of the head and neck area. It is concluded that although cocamidopropyl betaine is not a common allergen, it may be at least partially responsible for some cases of allergic dermatitis of the head and neck.