contact allergy to castor oil, but not to castor wax

Abstract

Ricinus communis (castor) seed oil (CAS 8001-79-4), a vegetable oil extracted from the seeds of Ricinus communis, is widely used in cosmetics and pharmaceuticals, and may be a cause of allergic contact dermatitis from these products. We present two patients with allergic contact dermatitis from cosmetics containing castor oil, in whom a correct diagnosis was achieved by patch testing castor oil ‘as is’. PEGylated and/or hydrogenated derivatives (the latter formerly also available from patch test allergen suppliers) and/or cosmetics containing these specific derivatives did not result in contact allergy or allergic contact dermatitis. This observation might be relevant for the manufacturing of cosmetics and pharmaceuticals. In the future, further research into the allergenicity of castor oil and its numerous derivatives, and their optimal patch test concentrations, may be desirable.