Hair Loss in Women
Not all women are blessed with enough thick, long hair to be able to donate to “Locks of Love.” According to the American Academy of Dermatology, nearly 30 million women in the United States have hereditary hair loss. Many other women simply experience marked thinning of their hair (diffuse hair loss) due to stress or other health problems.
Diffuse hair loss occurs when the normal hair cycle is interrupted by a trigger of any kind. These triggers include a wide variety of physiologic or emotional stresses, nutritional deficiencies, and endocrine imbalances.
Scalp hair grows in cycles, with each hair follicle undergoing 10 to 30 cycles in its lifetime. Normal hair cycle consists of four phases: anagen (active hair growth), catagen (involution), telogen (resting), and the exogen phase (the release of dead hair).
When the hair is growing normally, each hair follicle cycles independently. This keeps the density of the hair stable, as some hairs will be growing, while others are resting and others are shedding. Most people have about 100,000 scalp hairs with about 10% to 15% of these are in the telogen phase. Shedding of 100 to 150 telogen hairs per day is normal.
The most common type of diffuse shedding is telogen effluvium, in which anagen-phase hair follicles prematurely transition to the telogen phase, resulting in a noticeable increase in hair shedding at the end of the telogen phase 2 to 3 months later.
Telogen effluvium has many triggers. They include physiologic stress, emotional stress, medical conditions, dietary triggers, and medications.
Physiologic stress can include surgical trauma, childbirth, high fever, chronic illness, and hemorrhage. Telogen effluvium due to physical stresses will occur 2 to 4 months after the insulting stress.
Medical conditions which can cause diffuse hair loss in women include thyroid disease, hepatic failure, inflammatory bowel disease, and renal failure to name a few.
Dietary triggers include vitamin and/or mineral deficiencies, crash dieting, chronic starvation, and malabsorption syndromes.
When the hair loss is due to a medication, it starts about 12 weeks after starting the drug and continues while on the drug. Drugs known to sometimes cause hair loss in women include oral contraceptive pills, androgens, retinoids, beta-blockers, angiotensin-converting enzyme inhibitors, anticonvulsants, antidepressants, and the anticoagulants heparin and warfarin.
Telogen effluvium can be acute (lasting < 6 months), chronic (6 months or more), or chronic-repetitive. Length is most often determined by whether the trigger is acute and short-lived, chronic and ongoing.
Anagen hair shedding is due to the premature termination of anagen hair growth or anagen arrest, after an acute, severe metabolic insult. It is most often caused by treatment with chemotherapy or radiation, but may be due to underlying disease as with alopecia areata or heavy metal poisoning.
If you experience noticeable or increased thinning or your hair, seek medical advice. See a dermatologist who specializes in hair loss sooner rather than later. He/she should take your medical history, order blood tests when appropriate, and may even do a scalp biopsy.
Even once the trigger is identified, it is important for the woman to understand that the shedding may continue for up to 6 months after the trigger is removed or treated successfully. Truly noticeable thickening of the hair may take 12 to 18 month.
Treatment includes adequate nutrition. Stopping or changing a suspected drug trigger. Treating any underlying scalp inflammation (for example, seborrheic dermatitis or psoriasis). Treating any medical illnesses (ie thyroid disease, etc).
Though not a specific treatment, the application of the topical hair-growth promoter minoxidil (Rogaine) 2% and 5% to the scalp once a day can be useful in chronic diffuse telogen hair loss and chronic telogen effluvium.
Hair Loss in Women; N Engl J Med 2007; 357:1620-1630, October 18, 2007; Jerry Shapiro, M.D.
Diffuse hair loss: Its triggers and management. Cleveland Clinic Journal of Medicine 76: 361-367 (2009); Harrison, S., Bergfeld, W.