A black man with a broad-spectrum light sensitivity simultaneously showed an urticarial and contact sensitivity to a preparation containing 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (sulisobenzone). Both the benzophenone and sulfonic acid parts of the molecule were required for elicitation of the contact reaction, while benzophenone alone elicited the urticarial reaction.
Ramsay DL, Cohen HJ, Baer RL. Allergic Reaction to BenzophenoneSimultaneous Occurrence of Urticarial and Contact Sensitivities. Arch Dermatol. 1972;105(6):906-908. doi:10.1001/archderm.1972.01620090076017