Ultrastructure of the skin of patients treated with sodium aurothiomalate.

Skin biopsies from cases of rheumatoid arthritis treated with sodium aurothiomalate were examined with the electron microscope. Intralysosomal gold deposits were found in the macrophages of both normal-looking skin and from areas of erythematous rash that had developed as a toxic manifestation of gold therapy. The main difference between affected and normal-looking skin was the presence of numerous mast cells in the former. It is hence suggested that the dermatologic side-effects of gold are probably mediated by the release of vasoactive substances from mast cells and that vigorous administration of antihistamines to neutralise the liberated products of mast cells or an agent that interferes with degranulation of mast cells might have a palliative effect on the skin rash that sometimes develops during chrysotherapy.