Does an immune reaction to sebum in wounds cause keloid scars? Beneficial effect of desensitisation

Abstract

THE incidence of keloid scars in the Sudan is high, partly from the practice of tribal markings and partly from the increased incidence in many pigmented races. The problem in the Sudan has been previously studied by Crockett (1964) and more recently an excellent review of all aspects of keloid and hypertrophic scars has been published by Ketchum et al. (I 974). Ghicksmann (rgs I) and Mowlem (1951) in a histological and clinical study incriminated cut or detached portions of skin adnexae left behind in the wound. We were struck by the fact that keloids virtually never occur in areas where there are no sebaceous glands such as the genitalia, the pahn and the sole (Fig. I). We have therefore skin tested 40 people with keloid scars with an antigen prepared by homogenising sebum in olive oil to a I per cent concentration (WV). The homogenate was sterilised by a Sietz filter. One per cent chlorocresol was added and the homogenate stored at 4°C. An intradermal injection of 0.5 ml of this antigen was made on the volar aspect of the left forearm. As a control, on the opposite forearm, 0.5 ml of olive oil containing I per cent chlorocresol was similarly injected. The test was