What is it?
Acne vulgaris, or common acne, is a chronic skin condition that is characterised by spots that typically form over oily regions of the body (face, chest, neck and back). These spots, or lesions, form around hair follicles and the oil-secreting glands around them (known together as pilosebaceous units).
Acne can present in many different forms including what are called: blackheads (open comedomes or bumps), whiteheads (closed comedomes), papules (lesions of elevated, solid skin) and pustules (lesions containing pus).
What causes it?
Acne occurs when the hair follicles and glands around them become blocked and inflamed. Glands secrete an oily substance (called sebum) which is regulated by hormones. Male sex hormones (androgens) increase production while female sex hormones (oestrogens) decrease production.
Acne can occur when androgen levels result in excessive sebum production. These high levels of androgens also cause an increased hardening of the skin (keratinisation). The result is excessively rough hair follicles which become plugged with sebum and skin debris.
If debris builds up but the pore remains open blackheads (open comedomes) are formed. If the pore completely blocks, whiteheads (closed comedomes) are formed.
In more severe cases, the blockage can cause the wall of the hair follicle to burst, allowing bacteria to breach the skin’s barrier. This can lead to localised infections, causing inflammation, redness and pain. In the most severe cases of acne, this process can lead to irreversible scarring.
Environmental factors can also affect how much sebum is produced, including the application of cosmetic products to the skin, diet, humidity, stress and medications taken for other health issues.
How to treat it.
Due to the complex nature of acne, patients usually require multiple treatments that target different processes.
Unplugging the hair follicle pore allows the normal flow of sebum. In some patients, this can be achieved through the use of simple cleansers. In more severe cases, keratolytic agents (chemicals that break down skin keratin) are required, for instance, benzoyl peroxide.
Topical and oral antibiotics suppress bacteria that live on the skin surface. This reduces the risk of infection of blocked pores and subsequent inflammation.
Lowering androgens both reduces the volume of sebum production and reduces keratinisation (skin thickening). The combined oral contraceptive tablet is often used in female patients to achieve this.
Normalising skin keratinisation reduces the risk of pore blockage. Retinoids are a large family of drugs that have this action. They can be applied both topically (tretinoin) or orally (isotretinoin - known by the brand names Roaccutane and Rizuderm).