Why do some women lose their hair?

Why do some women lose their hair?

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)

It's normal to find shed hair in your hairbrush or on your sweater -- but excess hair loss can be a sign of trouble. In this video, Dr. Oz helps you tell the difference, and discusses the problems that may be behind your thinning scalp. 

Johns Hopkins Medicine
In women, hair loss is due to multiple causes. Hair loss occurs in two broad categories: scarring and non-scarring. Scarring hair loss is typified by patches of hairless, shiny smooth skin that may have redness on the edges. Causes of scarring hair loss include lupus; lichen planopilaris, a skin disease; or alopecias called folliculitis decalvan or pseudopelade of brocq. A biopsy is required to make a diagnosis.

Non-scarring hair loss is much more common in women and is caused by:
  • alopecia areata, characterized by round patches of hair loss on the scalp
  • tinea capitis, a fungal infection
  • female pattern hair loss, which is characterized by classic patterns of hair loss
  • medical causes
Medical causes include hypothyroidism, telogen effluvium, wherein large clumps of hair fall out in response to stressors such as severe illness, stress, pregnancy; or an endocrine imbalance like PCOS.

Common medications that can contribute to hair loss are cholesterol-lowering drugs, anticoagulants, antacids such as ranitidine (Zantac) and famotidine, medication for gout, anti-arthritics (naproxen) and vitamin-A derived drugs such as Accutane. Hair loss can also be cause by trauma to the scalp from radiation, surgery, chemical burns or traction (wearing of tight, pulling hairstyles over time).

Female pattern hair loss is the most common cause of hair loss in women. Incidence is difficult to determine but has been estimated to be as high as 50 percent of women by menopause. Its onset is subtle and there are variable patterns of loss but hairline is usually preserved. The age of onset is highly variable but there are usually two main peaks: women who lose in their 20s and 30s and women who lose their hair in perimenopause during their 50s and 60s.

Androgens, hormones that promote masculine characteristics and which play a significant role in male pattern baldness, are also implicated in female patter hair loss but it is less clear how.
Dr. Jack Merendino, MD
Endocrinology Diabetes & Metabolism
Most people do not realize how common hair loss is in women. But there are plenty of women out there, especially older women, who have lost so much hair they choose to wear a wig or otherwise hide the problem.

Roughly speaking, hair loss-also called alopecia-is divided into two main causes: hormonal and non-hormonal. Non-hormonal hair loss results from many problems. Nutritional deficiencies, such as in women who have lost a tremendous amount of weight rapidly from a major illness, following gastric bypass surgery or with severely calorie-restricted diets, can lead to significant hair loss. Specific vitamin or mineral deficiencies can lead to hair loss. Medications, such as chemotherapy drugs, may be toxic to hair follicles and cause alopecia. A common cause of hair loss is alopecia areata, an immune-mediated problem that usually causes patchy hair loss. This condition responds well to corticosteroid treatment. Major emotional stress will also often cause hair loss, sometimes quite severe. Again, the hair will usually return, but the hair loss itself only adds to the anxiety or depression that the woman is feeling.

There are two main causes of hormone-related hair loss. The first is hypothyroidism, or an under-active thyroid. Treatment of the thyroid problem usually results in the return of lost hair.

By far the most common hormone-related cause of hair loss in women is the same as in men: dihydrotestosterone, or DHT, a major metabolite of the primary male hormone testosterone. Both men and women produce DHT, and in a person with the genetic predisposition, DHT exposure leads to hair loss on the scalp. Because hair loss of this type depends both on a male hormone, or androgen, and on genetics, it is termed “androgenetic alopecia.” Women who have androgenetic alopecia lose their hair more slowly than men because their levels of DHT are lower. Medications that block testosterone, such as spironolactone (Aldactone), can be used to block the effects of male hormones in women. Prescription drugs that block DHT, such as finasteride (Proscar or Propecia) or dutasteride (Avodart) work on hair loss in men and theoretically should help women. However, these drugs have not been approved by the Food and Drug Administration for use in women and are potentially dangerous in a woman who might become pregnant because they can interfere with the sexual development of the fetus.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.