Effects of Steroids on the Skin

The skin is affected by a range of steroid hormones, including corticosteroids, oestrogens and androgens. Adrenocortical hormones have achieved prominence because of their effective use in dermatology. Their success as healing agents in a variety of conditions is only matched by our ignorance of how they work at the tissue level. In general it seems true that whatever can be measured, be it capillary blood flow in inflammation (Wilson, 1976), mitosis (Goodwin, 1976), epidermal thickness (Winter & Burton, 1976) or skin thickness (Kirby & Munro, 1976), is decreased by corticosteroids. Oestrogens pose an even greater puzzle, because there are conflicting views about their effects. The circumstantial evidence that appearance, texture and tone of skin are important sexual features of the female and that regressive changes occur after the menopause, favours the view that oestrogens stimulate the cutaneous tissues. Evidence that topical application of oestrogenic ointments to the backs of senile human subjects locally increased the size of the epidermal cells and accentuated the waviness of the basal layer (Eller & Eller, 1949) appeared to be reinforced by the claim that oestrogens stimulate epidermal cell division in mice (Bullough, 1953). Punnonen & Rauramo (1974) have revived the issue by the claim that, in women, epidermal thickness and thymidine-labelling index were decreased by ovariectomy, but could be restored by oral treatment with oestradiol succinate or oestradiol valerate. Against this must be set the failure to demonstrate any mitotic effects of systemically administered oestradiol in adult rats (Carter, 1953; Ebling, 1954, 1964), or any noticeable clinical improvement when oestrogen creams are applied to women’s faces (Behrman, 1954). Moreover, oestrogens in pharmacological doses appear to decrease rather than stimulate sebaceous activity. If the cutaneous effects of adrenocortical and oestrogenic steroids are ill-defined, the skin can, in contrast, be considered a specific androgen target. In particular, androgens stimulate sebaceous glands, whether distributed throughout the body or aggregated into specialized structures, and specialized apocrine glands in a range of animals (for review see Strauss & Ebling, 1970). They also affect hair follicles, particularly in man, where they stimulate hair growth on the body evenif, inconstitutionallydeprivedsubjects, they promote hair loss on the scalp. The responses of the sebaceous glands, in contrast to those of sexual hair, can be readily studied in animal models. However, discussion will be confined to experimental evidence from the rat and man, since specialized glands will be dealt with in this symposium (Johnson, 1976).