Oral β carotene therapy in actinic reticuloid and solar urticaria

Abstract

SUMMARY It is very difficult to find effective, acceptable protective agents for patients who are sensitive to long wave ultraviolet (UV) and visible radiation. It has recently been reported that oral β carotene is a useful photoprotective agent in erythropoietic protoporphyria (EPP) where sensitivity to visible light is important. The action of this drug has therefore been investigated in other diseases where sensitivity to the same part of the spectrum exists. Two patients with actinic reticuloid and three with solar urticaria, all sensitive to long wave UV and visible radiation were investigated before, during and after therapy with β carotene. Detailed monochromator tests were carried out and serum carotene and vitamin A levels determined at regular intervals. Therapy was continued from 2 to 12 months. Results showed that there was no objective or subjective evidence of improvement in any of the patients despite high serum carotene levels. Large variations in the dose of radiation required to produce a reaction were seen in all patients and it is essential to take account of this variation when assessing any photoprotective agent. It is possible that the mechanism of photosensitivity in actinic reticuloid and solar urticaria is quite different from that in EPP thus explaining the difference in the reported results of β carotene in the last disease.