Chronic photosensitive dermatitis due to phenothiazines.

Abstract

A 74-year-old man had eczematous eruptions on sun-exposed areas.Photopatch tests were positive to chlorpromazine and promethazine, and the action spectrum for the photosensitivity was in the long-wave ultraviolet light (UV-A) range. It was concluded that the chronic photosensitive dermatitis was due to phenothiazines. phenothiazines; photopatch test; photosensitivityChlorpromazine and other phenothiazines, such as promethazine, perphenazine, thioridazine and levomepromazine, have been widely used as tranquilizers, antipyretics, analgesics and/or antihistamines, and it is known that some of them may produce not only allergic contact dermatitis but also phototoxic and photoallergic reactions (Fisher 1967;Horio 1975;Horio et al. 1975). In the present case, photosensitive dermatitis was suspected because the eruptions were limited to sunexposed areas and became aggravated in summer. Patch tests and photopatch tests with phenothiazines and halogenated salicylanilides that are typical photosensitizers were performed, and it was confirmed that phenothiazines caused the development of the eruptions. Whether these lesions resulted from a phototoxic or a photoallergic reaction of phenothiazine was also discussed. REPORT OF A CASEA 74-year old farmer had a 10-year history of recurrent pruritic eczematous eruptions on sun-exposed areas. The lesions first appeared on the forearms and hands, and then spread to the face, nape and V-shaped area of the neck. According to the patient, the skin conditions became worse in summer and better in winter.He had no known systemic illness. There was no family history of photosensitivity-related diseases. A physical examination revealed scaling and lichenified dermatitis on the scalp, face, V-shaped area of the neck, extensor aspect of the forearms and the dorsa of the hands (Fig. 1). There was fissuring and infiltration in many sites, particularly on the hand backs. From these findings, it was suspected that the case was photosensitive dermatotis.Blood cell counts, urinalysis, serum GOT and BUN were all within normal limits. Histologic examination of the eruption on the left forearm showed hyperkeratosis, irregular acanthosis and mild, perivascular mononuclear cell infiltration of the upper dermis (Fig. 2).Received for publication, February 6, 1982. 223

Photoallergy

“…Other chemicals have also been identified as photocontact allergens including perfumed products like 6-methylcoumarin and musk ambrette, therapeutics like phenothiazines, antimicrobial agents, non-steroidal anti-inflammatory drugs (NSAIDs), and screen chemicals (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27).…”

“…Phenothiazines are organic compounds in various neuroleptic drugs like chlorpromazine and antihistamines like promethazine (22,23,55,114).…”