What is Acne vulgaris?
Acne vulgaris, also known as acne-juvenilis, is a chronic inflammation of hair follicle and sebaceous glands, which is easy to occur in the face and chest, back where high levels of sebum (oily secretion) are secreted. Acne is a self-limiting, multiple types of skin lesions, such as whiteheads and blackheads, pimples, pustules, nodules. These patients are often accompanied by high-level oily secretion, and after adolescence, most patients with acne are cured or relieved. In the past, acne is thought to be sebaceous gland disease, in fact, including hair follicles, sebaceous glands and the outer layer of skin.
Where is the largest distribution of sebaceous glands? Sebaceous glands are also a kind of skin appendage, widely distributed, almost all over the body. Sebaceous glands are divided into glands and ducts. Sebaceous glands usually have three types: 1, attached to the hair follicle, this type of sebaceous glands open in the hair follicle, becoming hair follicle - sebaceous gland system. 2, related to vellus hair, this type of sebaceous gland duct directly open on the surface. 3, has nothing with the hair, directly on the skin surface, also known as free sebaceous glands. The density of sebaceous glands is different at each site. Sebaceous glands are mainly distributed in the head, face, especially the eyebrows, nose, forehead, an average of 400 ~ 900 / cm2 glands. Sebaceous glands are also distributed in the central part of the trunk and axillary, about 100-150 / cm2 glands. So the head, face, chest, back and armpits are called high-level oily secretion parts. In the limbs, especially the lateral leg, sebaceous glands are scarce, so after bathing, the outer side of the calf is often dry, white debris appear.