What causes acne to itch?

Acne is the most common condition for many people in adolescence. When it occurs, patients will feel that the acne on their faces is very itchy. This situation will make patients feel very uncomfortable. This situation is mainly caused by clogged pores, so you must keep your face clean and hygienic, so that the effect will be better.

The occurrence of acne is closely related to factors such as excessive sebum secretion, blockage of the sebaceous gland ducts of the hair follicles, bacterial infection and inflammatory response. After entering puberty, the level of androgens, especially testosterone, in the human body increases rapidly, promoting the development of sebaceous glands and producing a large amount of sebum. At the same time, abnormal keratinization of the sebaceous gland ducts of the hair follicles causes blockage of the ducts, hindering the excretion of sebum and forming keratin plugs, also known as micro-acne. Various microorganisms, especially Propionibacterium acnes, multiply in large numbers in the hair follicles. The lipase produced by Propionibacterium acnes breaks down sebum to produce free fatty acids, while also attracting inflammatory cells and mediators, ultimately inducing and aggravating the inflammatory response.

Skin lesions often occur on the face and upper chest and back. Non-inflammatory lesions of acne appear as open and closed comedones. The typical skin lesions of closed comedones (also known as whiteheads) are skin-colored papules about 1 mm in size with no obvious hair follicle openings. Open comedones (also known as blackheads) appear as dome-shaped papules with significantly dilated follicular openings. Acne will further develop into various inflammatory skin lesions, manifesting as inflammatory papules, pustules, nodules and cysts.

Inflammatory papules are red, with a diameter ranging from 1 to 5 mm; pustules are uniform in size and filled with white pus; nodules are larger than 5 mm in diameter, feel hard and painful to the touch; cysts are located deeper and are filled with a mixture of pus and blood. These lesions may also fuse to form large inflammatory plaques and sinus tracts.

After the inflammatory skin lesions subside, pigmentation, persistent erythema, and depressed or hypertrophic scars are often left behind. Clinically, acne is divided into 3 or 4 grades according to the nature and severity of acne lesions: Grade 1 (mild): only comedones; Grade 2 (moderate): in addition to comedones, there are also some inflammatory papules; Grade 3 (moderate): in addition to comedones, there are also more inflammatory papules or pustules; Grade 4 (severe): in addition to comedones, inflammatory papules and pustules, there are also nodules, cysts or scars.

Based on the characteristics of onset in adolescents, distribution of skin lesions on the face, chest and back, and the main manifestations of polymorphic skin lesions such as whiteheads, blackheads, inflammatory papules, pustules, etc., it is easy to diagnose clinically and usually no other examinations are required. Sometimes it is necessary to differentiate it from rosacea, disseminated miliary lupus faciis, sebaceous adenoma, etc.