FROM AMONG the various factors which help to produce acne vulgaris, the most important are, undoubtedly, the sex hormones, and it therefore occurs principally during puberty. The androgens are especially acnegenic because of their stimulating effect on the pilosebaceous apparatus, as is clearly shown clinically and experimentally in rats1 and in human beings.* The usual premenstrual flare-up of the disease is explained by some investigators by the fact that in this period the amount of folliculin in the blood is at its lowest level with the result that the normal androgen-estrogen balance is altered in favor of androgen.
It is very likely that acne neonatorum, too, can be partially explained on a hormonal basis. The blood of a pregnant woman contains great quantities of estrogens, which readily pass through the placenta, enter the fetal bloodstream, and then in the newborn sometimes cause infantile seborrhea and, occasionally, also