Effect of plastic occlusive dressings on psoriatic epidermis.

TLDR: Serial biopsies have been performed on psoriatic lesions from the forearm in 13 patients in whom the lesions were occluded with plastic occlusive dressings for 2 weeks, and in 13 control Psoriatic subjects.

Abstract: SUMMARY.— Serial biopsies have been performed on psoriatic lesions from the forearm in 13 patients in whom the lesions were occluded with plastic occlusive dressings for 2 weeks, and in 13 control psoriatic subjects. A complete granular layer was not present in the occluded or control lesions prior td the study. In the occluded lesions a complete layer developed in 25 of the subsequent 65 biopsies but in only 2 of the 65 biopsies in the control group. In 10 of the 13 subjects the occluded lesions showed a complete granular layer at some stage during occlusion, although the time when it first appeared was variable. In 4 of these 10 patients the granular layer became incomplete after reformation during the period of study. Mitotic counts of the occluded psoriatic lesions showed a slight but significant fall at the end of the 2-week period but this did not occur in the control lesions. There was no significant depression of the mitotic count at the time when the granular layer first reformed. It is suggested that plastic occlusive dressings have some effect on psoriasis, and possible mechanisms of action are discussed.