STRUCTURAL FEATURES OF PHOTOALLERGY TO SALICYLANILIDES AND RELATED COMPOUNDS

[摘要] Photosensitivity (3200 to 4500 A) to halogenated salicylanilide molecules was studied in three patients by means of patch tests and photopatch tests. The findings suggest that in photosensitivity to these compounds: the 2 benzene ring moiety is not required; the activity resides in the salicylic acid ring; an active carboxyl group is necessary; the number of halogens on the ring is not crucial; an aniline ring halogenated in the para position elicits no reaction. Ultraviolet light probably Initiates salicylanilide photosensitivity by free radical formation which can lead to a variety of biochemical alterations, including changes in halogen content, direct cleavage of the 2 rings, enzymatic hydrolysis, facilitation of hapten-protein bonding (antigen formation), etc.