Acne is caused by over sensitivity of the immune system. Some people are hypersensitive to the bacteria which gets trapped in hair follicles. A whitehead results when the hair follicle becomes blocked. If this reaches the skin's surface and is exposed to the air it turns black and is therefore known as a blackhead. If the wall of the plugged follicle breaks, the affected area swells and becomes a pimple. When this happens below the surface, acne nodules or cysts can form. Squeezing spots can spread the problem and may lead to scarring. Acne can be exacerbated by stress.

Antibiotics are the most effective treatment. They can be taken by mouth, or used in a lotion, cream or gel, which should be applied daily before bedtime. Benzoyl peroxide works for many sufferers. It comes as a gel, lotion or cream, and should be spread thoroughly over dry skin.

Isotretinoin (sold as Accutane or roaccutane) can be used to treat severe cystic acne which does not get better with other treatments. A plus point is that it helps against scars forming, but a serious side-effect is that it can cause women to miscarriage or damage unborn babies and has been linked to mental health problems. Isotretinoin is an isomer of Vitamin A (13-cis-Vitamin A acid).

Formal Chemical Name (IUPAC)
3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,(E),4,6,8(Z,Z,Z)-nonatetraenoic Acid