Kaidbey K H, Kligman A M
Contact Dermatitis. 1978 Oct;4(5):277-82. doi: 10.1111/j.1600-0536.1978.tb04558.x.
A proprietary sunscreen-induced photosensitivity reactions in a small number of users. Laboratory study revealed that the reactions were of the photoallergic type and were due to the presence of a synthetic fragrance, 6-methylcoumarin. By photomaximization testing 6-methylcoumarin was found to be a potent photocontact allergen.