EFFECT OF PLASTIC OCCLUSIVE DRESSINGS ON PSORIATIC EPIDERMIS

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.     

Pharmacokinetic observations on dapsone in dermatitis herpetiformis

The pharmacokinetics of dapsone (DDS) and monoacetyldapsone (MADDS) following an oral dose of 150 mg DDS were studied in sixteen patients with dermatitis herpetiformis and seven normal subjects. No differences in DDS disposition were observed between the two groups. The maintenance dose of DDS for individual patients was not significantly correlated with jejunal biopsy morphology, DDS or MADDS half-lives, or the area under the plasma concentration-time curves for DDS or MADDS. DDS plasma protein binding was normal in patients and did not apparently determine the concentration of DDS in skin biopsies, for which the skin/plasma DDS concentration ratio was approximately unity. There was no undue representation of acetylator phenotype in the patient group and no correlation between maintenance dose and MADDS/DDS ratio was noted. The determinants of the maintenance DDS dose have not been found. This may relate to pharmacodynamic differences, but alternatively the concentration of oxidative metabolites rather than DDS or MADDS could be responsible for the therapeutic activity in dermatitis herpetiformis.