Female hair loss

The average person loses 100 hairs a day from the scalp as part of the natural cycle of hair growth. A hair grows for several years, goes dormant for a few months, and then dies and falls out. In normal circumstances the hair follicle then generates a new hair in its place. Female hair loss, or alopecia, occurs when shed hairs do not spontaneously regrow. Hair loss can be localized or happen all over the scalp and body and has a number of different causes.

Telogen effluvium

• Telogen refers to the dormant stage of a hair's life cycle, and telogen effluvium occurs when this dormant stage is prolonged and shed hairs are not replaced. Telogen effluvium can be acute, resulting in almost complete hair loss two months after a shock to the system, or chronic. Acute telogen effluvium can be caused by high fever, pregnancy and childbirth, surgery, psychological stress, thyroid problems, and medications such as beta blockers and antidepressants. Many cases of acute telogen effluvium end with the hair regrowing once the cause of the shock is removed. Chronic telogen effluvium results in long-term hair loss spread evenly across the scalp but does not cause total baldness. Its causes are not understood.

Androgenetic alopecia

• Androgenetic alopecia in men is the cause of male pattern baldness and in women causes the much less common female pattern hair loss. In women it results in thinning of the hair on the crown but not at the front of the head and rarely causes total baldness. It seems to be genetic and is most common after the menopause. Up to 75 percent of women aged 65 and over suffer from androgenetic alopecia. It can be treated with the drug minoxidil.

Trichotillomania

• Also known as trichotillosis, this an obsessive compulsion to pull individual strands of hair from the scalp and sometimes other areas of the body. Over a period of time it results in irregular patches of hairless scalp. Trichotillomania is triggered by depression, anxiety and obsessive compulsive disorder and is also common in people suffering from post traumatic stress syndrome. It is classified as an impulse control disorder and can be subconscious, especially in children, or focused and deliberate. Treatment is psychological and includes habit reversal training to teach sufferers to recognise and resist the impulse to pull out hairs.

Alopecia areata

• This causes rapid and patchy hair loss, commonly more severe on one side of the head than the other and can also affect body hair. Occasionally it can result in the loss of all hair all over the body, which is a condition known as alopecia universalis. Alopecia areata is believed to be caused by an autoimmune abnormality that causes the body's immune system to attack hair follicles. It is sometimes associated with other autoimmune diseases such as lupus and rheumatoid arthritis and is most common in children and young adults. In general hair will regrow within a year, but the condition can be permanent. It is treated with steroids and immunosupressants, although reducing stress and applying essential oils such as cedarwood oil are also considered beneficial.

Chemotherapy

• The drugs used in chemotherapy target all rapidly dividing cells in the body, including those in hair follicles. Chemotherapy can result in partial or complete hair loss in men and women. The effects are unpredictable and not all chemotherapy patients will suffer from loss of hair. Radiation treatment causes localized hair loss and will cause complete baldness when used to treat metastatic brain cancer.

Other causes

• Traction alopecia is caused by tight hairstyles such as cornrows or pigtails. In severe cases these can scar the scalp and result in permanent hair loss. Perms that use oil at high temperatures can damage hair follicles and cause hairs to fall out and not regrow.