What is alopecia? Alopecia is the medical term for baldness or hair loss. It can affect the entire scalp or smaller localised areas and may be temporary or permanent. Other parts of the body where hair normally grows can also be affected. Alopecia may have an underlying cause or may simply be part of the natural ageing process.

The commonest form of alopecia is male-pattern baldness (also known as androgenic alopecia or common baldness). Male pattern baldness tends to run in families. It usually starts in the late 20s or early 30s. Initially there may be just some thinning of the hair and a receding hairline. Gradual hair loss occurs at the temples and crown of the head. Eventually, the bald spots increase in size until the entire top of the head is bald and hair remains on the back and sides of the head only. In some men, total baldness can occur. Men who start losing their hair at an early age tend to develop more extensive baldness.

Female pattern baldness occurs in some women as they get older and becomes more noticeable after the menopause. The hair begins to thin at the front and crown of the head. This also tends to run in families.

Small areas of patchy hair loss are caused by a condition called alopecia areata. The patches of baldness are about the size of a large coin and may come and go. Alopecia areata affects about 1 in 100 people, mostly teenagers and young adults. Other areas besides the scalp may be affected.

Alopecia universalis is a severe form of alopecia areata that results in permanent loss of all body hair, including eyebrows, eyelashes, and hair in the pubic area and armpits.