The antioxidant N-acetylcysteine  (NAC) has an ability to decrease proliferation of skin cells. The authors treated a patient with a severe form of dry skin called lamellar ichthyosis satisfactorily treated with topical N-acetylcysteine. (NAC) is a thiol that reacts with reactive oxidative intermediates and replenishes the intracellular cysteine necessary for the production of glutathione, an endogenous antioxidant. 

The investigators used a water-in-oil emulsion containing 10% NAC. Placebo consisted of the same emulsion without NAC.

The patient applied the cream twice daily on the skin. NAC is labile and tends to break down, releasing sulphur-containing compounds. The water-in-silicone emulsion improves stability and reduces malodor. Recent studies show that NAC suppresses proliferation of fibroblast cells

COMMENT: This appears to be an incredibly safe, non-toxic and relatively low cost approach for a very difficult problem. Although the treatment was not used for psoriasis, it seems likely that it would be beneficial here since both diseases have very similar underlying disorders of an increase in cellular proliferation.