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The sebaceous glands of man show age-related differences in their activity as determined by quantitative and qualitative examination of sebum. Sebaceous secretion is low in children and begins to increase in mid- to late childhood under the influence of androgens. This rise continues until the late teens, after which no further significant change takes place until late in life. In elderly men, sebum levels remain essentially unchanged from those of younger adults until the age of 80. In women, sebaceous secretion decreases gradually after menopause and shows no significant change after the 7th decade. The most likely explanation for the decrease in sebaceous gland secretion with age in both men and women is a concomitant decrease in the endogenous production of androgens. Although surface lipid levels fall with age, paradoxically the sebaceous glands become larger, rather than smaller, as a result of decreased cellular turnover. Nonetheless, as the higher surface lipid levels after administration of fluoxymesterone (a synthetic testosterone derivative) indicate, the glands have the capacity to respond to androgens.

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Human epidermal surface lipids were collected by an ethanol wash and the ceramides were quantified by thin-layer chromatography-photodensitometry. Six ceramide fractions were isolated and the structural components of each were analyzed in detail. The most unusual of the epidermal ceramides contained a sphingosine base with amide-linked 30- and 32-carbon omega-hydroxyacids and an ester-linked nonhydroxyacid, 41% of which was linoleic acid. The proportion of linoleic acid in the analogous ceramide from comedones was 6%. This supports the hypothesis that a localized insufficiency of linoleic acid in the follicular epithelium is an etiologic factor in comedogenesis.

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Fourteen patients with treatment-resistant cystic and conglobate acne were treated for four months with oral 13-cis-retinoic acid, a synthetic isomer of naturally occurring all-trans-retinoic acid. The average dose was 2.0 mg per kilogram per day. Thirteen patients experienced complete clearing of their disease; the other had 75 per cent improvement, as determined by the number of acne nodules and cysts present before and after therapy. Prolonged remissions, currently lasting as long as 20 months after discontinuation of therapy, have been observed in all 14 patients. Clinical toxicity was limited to the skin and mucous membranes in most patients and was dose dependent and rapidly reversible upon discontinuation of therapy. The mechanism of action of 13-cis-retinoic acid in the therapy of acne probably involves a direct inhibitory effect of the drug on the sebaceous gland.

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