Although a number of factors contribute to acne, the initiating event is hormonal stimulation of the sebaceous glands beneath the skin. “The sebaceous glands produce sebum, the oily substance that gets transmitted onto the skin’s surface,” explains Dr. Eichenfield. Each bulb-shaped gland leads to a narrow duct called a follicle; each follicle contains a strand of hair.
“Once kids reach puberty,” he continues, “not only do the glands become more active, but the chemical composition of the sebum changes.” Ordinarily, a follicle’s inner lining sheds dead cells into the sebum, which gets deposited onto the skin, waiting to be scrubbed away.
For reasons that aren’t clear, in acne the cells clump together and plug the opening, or pore. This prevents the oil from escaping. It also forces bacteria that normally reside in the skin (called Propionibacterium acnes, or P. acnes), to proliferate inside the narrow follicle. Eventually the sebum seeps out of the opening. If chemicals produced by P. acnes inflame the skin, a reddish pusfilled pimple begins to grow there.
Acne, whiteheads and blackheads are all by-products of the same process. Acne refers to an enlarged follicle that protrudes from the surface of the skin; whitehead describes a plugged follicle that remains just beneath the surface. When the follicle opens partially to reveal a black speck the size of a pinhead, it is called a blackhead. Contrary to popular myth, “the discoloration is pigment, not accumulated dirt,” stresses Dr. Eichenfield. “Blackheads are just another type of acne.” Still other acne lesions include:
- Paranasal erythema: an early form of acne commonly seen in kids on the cusp of puberty.
- Papule: an inflamed, small, pink bump that is tender to the touch.
- Nodule: a large, solid lesion lodged far below the skin’s surface; is frequently painful.
- Cyst: another painful deep-seated lesion. Cysts, however, are inflamed and contain pus. They can also leave scars. Only one in twenty cases of acne are this severe.