Phototoxic contact dermatitis from 5-methoxypsoralen in aromatherapy oil.

Abstract

Bergamot (Citrus bergamia) oil is obtained from the rind of small orange‐like fruits native to Italy. It is obtained by expression when the fruits have almost yellowed. Its light citrussy aroma, in addition to long‐standing use in the cosmetic industry and to flavour tea, is used in aromatherapy. The essential oil of bergamot contains various compounds, including the furocoumarins citropten (5,7‐dimethoxycoumarin (5,7‐DMC)) and bergapten (5‐methoxypsoralen (5‐MOP)) (1). In combination with exposure to sun, bergamot oil stimulates melanogenesis (2), hence potentially protecting the skin against erythema and even cutaneous cancers (photo‐chemoprotection) (3). However, both citropten and bergapten are known to be photomutagenic (4, 5) and phototoxic, bergapten being the more toxic.Until recently, 5‐MOP was frequently used in suntanning preparations. The status of 5‐MOP in the EU is currently being discussed, though there is already an un‐official ban in the UK on its use in sunscreen products. IFRA recommends in its code of practice that, when used for application on areas of skin exposed to sunshine, excluding bath preparations, soaps and other products that are washed off the skin, bergamot oil should not be used in consumer products at above 0.4%. Major manufacturers of perfumes comply with the IFRA code of practice which limits 5‐MOP to 75 ppm in perfume, and distil oil of bergamot to substantially remove 5‐MOP (6). 8‐MOP is prohibited in cosmetic products except the natural content of essences.