The most important of all the blemishes of the complexion is undoubtedly acne. The cause of nearly all pimples and spots on the face, acne is an affection which gives trouble and annoyance to nearly everyone.
Acne is an affection of the sebaceous glands, and to fully understand its causes and treatment we must briefly review the functions of the sebaceous glands themselves.
By the side of each hair root, two small glands are situated. These glands secrete a thick oil, not unlike very thick cream in appearance. This oil, which is the natural grease of the hair, is necessary to maintain the hair in health, and to prevent it from splitting. the secretion is called sebum and the glands which secrete the sebum are called the sebaceous glands.
We have before told you that the face is covered with fine hairs. Each of these hairs has two sebaceous glands to oil it. Now, when a child has passed her fifteenth year and is on the threshold of adult life, the hairs on her face take on a rapid growth, and in this comparatively sudden growth the sebaceous glands share. If all went well, the glands would increase in regular ratio with the hairs, and there would be no acne spots on the face. But everything goes well, but seldom for extremely few persons pass from fourteen to twenty-five without developing, at all events, one acne spot.
The beginning of trouble is that in one gland the sebum dries over the entrance and converts the gland into a closed sac. The gland still continues to secrete, for all the glands in the body will go on working till they are destroyed. The gland still works and still secretes sebum, but the latter cannot get out, and so collects in the gland and gradually distends it.
Upon the surface the distended gland shows but as a small white body about as big as a pin's head, and is called a "milium" or "whitehead". If the milium be squeezed between the fingers, the mass of dried sebum which is plugging the mouth of the gland is forced out, and the white semi-solid secretion follows in a long worm-like thread. This has given rise to the idea that the sebum is really a worm, and whiteheads are frequently called skin worms, especially in advertisements for quack remedies.
The milium or whitehead is therefore the beginning of acne. The condition may stop here; the milium may be squeezed out, or the plug which closes its orifice may be accidentally displaced, and the gland will then return to its normal condition. But usually other changes occur before long. The plug of dried secretion which is filling up the entrance may become infected with one of the colour producing bacteria and become blackened. The spot is now called a "blackhead" or "comedone".
There is a widespread belief in the public mind that comedones only occur on the faces of persons who do not wash themselves sufficiently. This is a thoroughly false doctrine; there is no doubt that the colouring of the blackhead is neither dirt, nor is it due to dirt; it is the product of the growth of certain organisms.
Like the milium, the blackhead may be squeezed out either by accident or design, and the gland may return to the normal condition, or it may go on to a further stage of the affection of acne.
If a milium or comedone is left alone and is neither squeezed out nor inoculated with germs, it will continue to grow indefinitely and in time may form an immense tumour. Such a tumour is called a sebaceous cyst - that is, a hollow growth filled with sebum. By the public these growths are called "wens". They are exceedingly common, especially on the head and back. They may grow to an immense size, equal to the head of a child in bulk. They are frequently multiple.
But another calamity may overtake a milium or comedone which, though less annoying to the possessor than a sebaceous cyst, is more detrimental to the sebaceous gland, for it usually ends by destroying it altogether. The sebaceous gland, being full of sebum and having its mouth plugged, readily becomes attacked by micro-organisms which convert the gland into a small abscess or acne pustule.
Wherever you squeeze out a milium or a comedone, a small round hole is left which is distinctly visible to the naked eye. This hole is the dilated mouth of the gland and will gradually get smaller as the gland itself returns to the normal condition. From this dilated mouth the secretion runs away in large quantities, and gives the skin a greasy appearance when wet and a scaliness when dry. This abnormal secretion will also stop after a short time.
Whenever a milium or comedone is attacked by organisms it is rapidly converted into a small abscess. the matter from the abscess is either squeezed out or else opens of itself, and the whole gland is extruded. A scar is invariably left wherever an acne pustule has been. The matter from any pustule is of a highly infective character, and one small acne spot contains sufficient organisms to inoculate every sebaceous gland in the body. This is the true explanation of the well observed fact that pustules on the face frequently recur.
Having briefly glanced at the essential points in the pathology of acne, let us now turn our attention to the consideration of the causes and clinical history of the condition.
Acne is a disease of the sebaceous glands, and therefore we should expect it to manifest itself in those places where the sebaceous glands are most numerous, and at that time of life when they are most physiologically active.
In both sexes, at about the age of fifteen the hairs on the face, which before were insignificant, suddenly start to grow with great vigour. The sebaceous glands have to keep pace with the hairs, so that it is at that period when acne is most frequent. And as the hairs of the face of men grow with far greater rapidity and vigour than they do in women, so is acne infinitely more common in young men than in young women.
Acne is rare before the fourteenth year and it is uncommon after thirty. It is a condition almost confined to adolescence and early adult life. It is a local disease of the sebaceous glands and has nothing to do with the state of the blood. Its most frequent seats are the forehead, the temples, the chin and the sides of the mouth; but sometimes it covers the whole of the face, and not very uncommonly it spreads all over the body. But since it is a disease of the sebaceous glands, it therefore cannot occur where there are no hairs. The skin of the palms of the hands and the soles of the feet are the only places where acne spots cannot occur, for they are the only parts of the body destitute of hair.
(To be concluded in Part Two: Treatment.)