Experimental studies on phototoxic and photoallergic reaction by the skin window technique.

The differentiation of photoallergic contact dermatitis by 3,3', 4', 5-tetra-chlorosalicylanilide from phototoxic contact dermatitis by 8-MOP in guinea pigs was studied by skin window technique. Based upon the results, it may be concluded that the photoallergic reaction can be differentiated from phototoxic reaction by the appearing pattern of basophilic leukocytes.