• MEDICAL CONDITION
medical condition generic image

Alopecia

DESCRIPTION

Partial or complete loss of hair is called alopecia. Hair loss usually develops gradually. It may be patchy or all over (diffuse). You lose roughly 100 hairs from your head every day. The scalp contains about 100,000 hairs.

Both men and women tend to lose hair thickness and amount as they age. This type of baldness is not usually caused by a disease. It is related to aging, heredity, and changes in the hormone testosterone. Inherited, or pattern baldness, affects many more men than women. Male pattern baldness can occur at any time after puberty. About 80% of men show signs of male pattern baldness by age 70.

Physical or emotional stress may cause one half to three quarters of scalp hair to shed. This kind of hair loss is called telogen effluvium. Hair tends to come out in handfuls while you shampoo, comb, or run your hands through your hair. You may not notice this for weeks to months after the episode of stress. Hair shedding decreases over 6 to 8 months. Telogen effluvium is usually temporary. But it can become long-term (chronic).

Other causes of hair loss, especially if it is in an unusual pattern, include:

  • Alopecia areata (bald patches on the scalp, beard, and, possibly, eyebrows)
  • Anemia
  • Autoimmune conditions such as lupus
  • Burns
  • Certain infectious diseases such as syphilis
  • Excessive shampooing and blow-drying
  • Hormone changes
  • Thyroid diseases
  • Nervous habits such as continual hair pulling or scalp rubbing
  • Radiation therapy
  • Tinea capitis (ringworm of the scalp)
  • Tumor of the ovary or adrenal glands
  • Hair styles that put too much tension on the hair follicles
  • Bacterial infections of the scalp

medlineplus.gov/ency/article/003246.htm