Abstract
As it is not so easy to differentiate the photoallergic reaction from the phototoxic reaction, we studied experimentally whether the skin window technique can be applied for this differentiation or not. The phototoxic contact dermatitis due to 8-MOP and the photoallergic contact dermatitis due to 3, 3′, 4′, 5-TCSA induced in guinea pigs were examined by the skin window technique and the following results were obtained ; 1) in the phototoxic reaction, at 3 hours, neutrophilic leukocytes appeared in great numbers. At 8 hours, mononuclear cells were slightly increased in percentage and neutrophilic leukocytes were decreased. At 16 and 24 hours, the percentage of neutrophilic leukocytes was again high. The percentage of neutrophilic leukocytes was higher than that of control animals. Neither basophilic nor eosino-philic leukocytes were observed. 2) in the photoallergic reaction, the pattern of the appearence of neutrophilic leukocytes and mononuclear cells showed no differences as compared with the phototoxic reaction. But a significant number of basophilic leukocytes were observed and their appearence was gradually increased in percentage with time laps. Eosinophilic leukocytes were also observed, but the percentage and time course of their appearence showed no definite pattern. Based upon the above results, it may be concluded that the photoallergic reaction can be differentiated from the phototoxic reaction by the appearence of basophilic leukocytes.
