Hair loss
Baldness in men
The most common type of hair loss starts in males from about the age of 30. It is known as androgenetic alopecia or ‘male pattern baldness’. It is thought to be hereditary, and dependent on the male hormone, testosterone.
How quickly or slowly baldness develops, and the pattern of hair loss, appear to be genetically determined. Although this type of baldness can also affect women, the pattern of baldness is different in males and females.
Other forms of baldness
Hair loss that is not hereditary may be caused by pregnancy, hormonal or other medicines, severe nutritional deficiencies, chemotherapy, auto-immune disorders, an under-active thyroid or scalp trauma, including reactions to hair care products and hair grooming methods.Telogen effluvium is a form of temporary generalised hair loss that may follow childbirth, illness, operation or severe shock.
Alopecia areata is an auto-immune condition, usually causing discrete patches of hair loss, but may cause total baldness. The hair usually (but not always) re-grows.
Trichotillomania is a condition of compulsive hair picking or pulling that can lead to patches of near complete hair loss.
How does hair grow?
The human scalp contains about 100,000 follicles. These anchor the hair to the skin and contain the cells that produce new hairs.Normal hair grows in 3 phases.
- The anagen or follicle growing phase starts growing the new hair. This phase is genetically determined and can vary from 2 to 5 years (the average is just under 3 years).
- The catagen phase is a transition stage between the growing and resting phases.
- The telogen or resting phase is a mature hair with a root, which is held very loosely in the follicle. The telogen phase generally lasts about 3 months. About 100 telogen hairs are lost from the human scalp each day.
In hereditary hair loss, the follicle becomes smaller, the anagen phase is shorter and the telogen hairs are shed faster.
When should you seek medical advice?
You should seek medical advice for hair loss if:- you are a woman who has recently given birth;
- you have been diagnosed with (or think you may have) an auto-immune disorder such as systemic lupus erythematosis (SLE), nutritional deficiency or thyroid disease;
- you have been recently treated with chemotherapy or have used a hormonal medicine;
- the hair loss occurs in discrete patches;
- the hair loss is associated with scaling or inflammation of the scalp;
- you also have loss of body hair;
- you are aware you have a compulsive hair-pulling habit; or
- the hair loss cannot be explained by hereditary factors.
Last Reviewed: 08 September 2006
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