Acne vulgaris (acne) is an extremely common condition, often affecting people during puberty and adolescence. Most people are affected at some point during their lives, and symptoms can range from mild to severe.
Acne is caused by chronic inflammation, with or without localised infection, in pockets within the skin known as the pilosebaceous unit. The pilosebaceous units are the tiny dimples in the skin that contain the hair follicles and sebaceous glands. The sebaceous glands produce the natural skin oils and a waxy substance known as sebum.
Acne results from increased production of sebum, trapping of keratin (dead skin cells) and blockage of the pilosebaceous unit. This leads to swelling and inflammation in the pilosebaceous unit. Androgenic hormonesincrease the production of sebum, which is why acne is exacerbated by puberty and improves with anti-androgenic hormonal contraception. Swollen and inflamed units are called comedones.
The Propionibacterium acnes bacteria is felt to play an important role in acne. This is a bacteria that colonises the skin. It is thought that excessive growth of this bacteria can exacerbate acne. Many of the treatments of acne aim to reduce these bacteria.
There is significant variation in the severity of acne. It presents with red, inflamed and sore “spots” on the skin, typically distributed across the face, upper chest and upper back.
There are few terms used to describe the appearance of the lesions: