The phenothiazine derivatives have become one of the principal drugs for the treatment of psychiatric disorders. Along with their therapeutic action, an occasional untoward effect is observed on any of the physiological systems. In man, dermatological lesions that have been observed include contact sensitivity, generalized eruptions and photosensitivity. Photosensitivity may be divided into two kinds of reactions: 1. the erythema reaction producing an accelerated and intensified sunburn, resulting from exposure to ultraviolet light below 3200 A (C~ et al.) ; and 2. the pigmentation reaction, producing a marked increase in melanin deposition particularly in the dermis, resulting from exposure to ultraviolet light above 3200 4. The erythematous reaction is common in patients receiving phenothiazines, especially chlorpromazine (Thorazine). What is less common, however, is the pigmentation reaction which is found in some patients receiving prolonged ehlorpromazine therapy. This pigmentation is characterized by marked darkening of the skin resulting in a slate gray color which at times has a violet hue. The discoloration is restricted to exposed areas of the body.
Recent articles described this skin reaction (G~]~I~]~ and B~R~; Z]~LICKSON and ZEI, r~) ; and Smith, Kline and French Laboratories, the manufacturers of chlorpromazine, have warned all physicians of the sideeffect. The impression is given that this is a newly discovered skin reaction; however, it is not new, having been known to us since 1956. Since then we have observed several cases and will describe three of the more severe.