Inhibition of Keratinizing Structures by Systemic Drugs

The document discusses how various systemic drugs, including vitamin A, thallium, antineoplastic compounds, hypocholesteremic drugs, chloroprene dimers, mimosine, and anticoagulants, interfere with the development of human hair and the horny layer of the skin. The hair root is more susceptible to these compounds than the epidermis, with growing hairs, particularly on the scalp, being most affected. The mechanisms by which these drugs cause hair loss and disturbed epidermal differentiation are not fully understood, but they involve diverse pathways such as metabolic diversion, interference with cystine utilization, and inhibition of mitosis. The study suggests that these side effects, while nonspecific, could provide valuable insights into the biology of keratinizing structures and the pharmacologic effects of these drugs, potentially aiding in the treatment of scaling skin diseases and cancer.