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Hair Loss Types

Alopecia is the medical term for hair loss or baldness in an area of the body where hair is normally present. Usually, it refers to loss of scalp hair. Two patterns of hair loss are female-pattern baldness (general thinning with moderate loss at the hair line and crown) and male-pattern baldness (receding hair line with moderate to extensive loss at the crown).

Hair loss can refer to many different problems - from mild hair thinning to total baldness - and these can occur for many different reasons. Medically, hair loss falls into several categories, including:

Androgenic Alopecia

In men, hair loss may follow the typical "male" pattern (receding front hairline, and/or thinning hair at the top of the head). This is the most common type of hair loss, and it can begin at any time in a man's life, even during his teen years.  Quite similarly, most women will develop at least mild female pattern alopecia. The pattern is different however, as thinning occurs over the whole top or crown of the scalp, sparing the front of the scalp, so that the "frontal recession" seen in men does not occur.

Androgenic alopecia accounts for 95 percent of men's hair loss. It is caused by heredity, hormones, and age. It leads to progressive miniaturization of hair follicles and shortening of the hair's growing cycle. The active growth phase becomes shorter and the hair follicles smaller, and thus the hair follicles gradually produce finer and thinner hairs. Eventually, there is no growth at all, which results in less scalp coverage.

The process of hair loss can begin, for some individuals, as soon as in their teens, while others begin to notice thinning hair in their 20s or 30s, or even later in life.

Alopecia Areata

Alopecia areata results in the appearance of roughly circular bald patches on the scalp. The skin in the affected area is smooth and soft and has no hair at all. 

Unlike androgenetic alopecia, alopecia areata often generates an abrupt hair loss. It is now known to be an auto-immune disorder, which causes hair follicles to stop producing hair, and there is commonly a hereditary factor. Research has shown that in alopecai areata the hair follicles in the anagen growing phase become a target for attack by auto-immune cells. Hair loss is sudden, sometimes even overnight.

Alopecia areata may be no more than a few bald patches that appear and then regrow hair. If the patches are small, the chances of regrowth are very good.

Diffuse alopecia areata leads to sudden thinning without the bald patches. This condition is far less common than the bald patches described above. Alopecia Totalis is the term used when all the hair on the head is affected, and when all the body hair is affected too, that will be called alopecia Universalis. When this happens, the chances of regrowth are poor.

Telogen Effluvium

This is a generalized, diffuse hair loss that happens 2 to 3 months after a major body stress, such as a prolonged high fever, major surgery, or serious infection. It may also happen after a sudden change in hormone levels, especially in women after childbirth.

Drug Side Effects

Certain medications have hair loss as annoying side effect, especially medications such as: lithium; beta blockers; the "blood-thinners", warfarin and heparin; amphetamines; levodopa, and other drugs. Daunorubicin, and other medicines used in cancer chemotherapy, can also cause sudden generalized hair loss.

Symptom of a Medical Illness

Hair loss can be one of the symptoms of a medical illness, such as: lupus erythematosus; syphilis; a thyroid disorder (hair loss occurs in both hypothyroidism and hyperthyroidism); sex hormone imbalance; sarcoidosis; metastases (cancer spread) to the skin (this would cause a dime or larger size area of hair loss, typically with a hard underlying bump); or a serious nutritional problem, especially a deficiency of protein, iron, zinc, or biotin. These deficiencies are not uncommon in women on weight loss diets or those who have very heavy menstrual flow.

Tinea Capitis

Fungal infection of the scalp. This form of patchy hair loss happens when the scalp is infected by the fungus Trichophyton tonsurans. This causes the hair to break off right at the scalp surface and the causes the scalp to flake or become scaly.

Traumatic Alopecia

This man-made form of hair loss is caused by hairdressing techniques that do one of the following : pull the hair (tight braiding or corn-rowing); expose hair to extreme heat and twisting (curling iron or hot rollers); or damage the hair with strong chemicals (bleaching, hair coloring, permanent waves).

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