Excessive hair loss can be caused by recent surgery, diet, medications, chemotherapy, stress, or other causes. It can also be caused by hormonal changes. Hair is genetically programmed to either be sensitive to or resist hormones that appear in puberty. It’s this part of the genetic program that most frequently causes balding, or alopecia (al-o-PEE-she-uh).
Androgenetic Alopecia
Androgenetic alopecia is the scientific name for the genetic predisposition that is responsible for 95% of all pattern hair loss in both men and women. Pattern hair loss refers to the progressive loss of hair in predictable stages, over predictable areas of the scalp. The pattern of loss typically varies between men and women. In men, androgenetic alopecia can begin as early as the teens and usually peaks at about age 40. Women are most frequently affected after menopause.
Certain hair follicles in people with androgenetic alopecia are susceptible to the hormone Dihydrotestosteron, or DHT. If enough DHT is received over a long enough period of time, the follicles will eventually stop producing hair. The incidence of androgenetic alopecia hair loss increases with age.
Susceptible follicles are usually on the front and top of the scalp. Follicles on the back and sides of the scalp usually do not attract DHT, and they continue to produce hair. It’s this difference in the location of susceptible follicles that results in the common male pattern of a receding hairline followed by balding on the top of the head, until all that remains is a fringe around the sides and back.
Contrary to what many people believe, pattern baldness can be inherited from either parent. Surgical and non-surgical treatments are available for androgenetic alopecia.
Alopecia Areata
Alopecia areata is an immune system disorder that affects about 1%-2% of the population. The condition is characterized by temporary, patchy hair loss on the scalp and/or body. It usually starts with small round patches of baldness. Most cases of alopecia areata begin in childhood. The affected hair follicles become small, slow down production and grow no visible hair for months or years. Like androgenetic alopecia, the scalp appears normal.
Treatments for alopecia areata include:
Cortisone injections-This treatment may stimulate new hair growth, but it does not prevent new bald patches from developing. Cortisone pills may be needed for more extensive cases.
Topical Minoxidil, 5% Solution-Patients apply Minoxidil twice daily. Scalp, eyebrows and beard may respond.
Anthralin cream or ointment-This is applied to the affected area and washed off after a short period of time, usually 30-60 minutes later. New hair growth may be expected in eight to twelve weeks.
Topical immunotherapy-Chemicals are applied to the scalp which induces a rash which may cause hair growth in 40% of patients.
Other Causes of Hair Loss
Although androgenetic alopecia is the usual culprit, other conditions and factors can also cause a temporary or sometimes permanent loss of hair. These include: - Normal processes of aging (involutional alopecia)
- Traumatic injuries, such as severe burns
- Skin infections
- Chemotherapy
- Radiation therapy (usually only on areas where the radiation is targeted)
- Medication side effects (almost always temporary) from prescription drugs, such as blood thinners, antidepressants, birth control pills, and high blood pressure medications
- Tight hairdos and elastic bands that exert a constant pull (traction alopecia)-usually temporary; sometimes permanent
- Certain diseases and conditions, such as diabetes, lupus, immune system disorders, and polycystic ovary syndrome
- Overactive or underactive thyroids
- Incorrectly applied hair color and chemical relaxers
- Stress or illness.
- Childbirth (some women lose large amounts of hair after delivery).
Pattern Baldness in Men - Men are far more likely than women to have hair loss as they age, to begin losing hair earlier, and to lose extensive amounts of hair.
- In men, the follicles programmed to stop growing first are usually located at the hairline and on the top of the head. This causes the typical male “receding hairline” of middle age, followed by moderate to extensive loss at the crown.
- More than 35 million men in the United States are estimated to have the androgenetic alopecia predisposition.
- Male-pattern baldness is permanent.
Pattern Baldness in Women - Women are much less likely than men to experience hair loss as they age. Those who do, usually begin losing their hair later in life than do men, and lose less hair overall.
- In women, the follicles programmed to stop growing are usually spread diffusely throughout the scalp, rather than at the hairline or crown. Overall thinning may result, but bald spots and receding hairlines are rare.
- In the United States, approximately 21 million women are estimated to have the androgenetic alopecia predisposition.
- Estrogen hormones can counteract the effects of the hormone usually responsible for hair loss. Women have more estrogen in their blood system than do men, so even those with a genetic predisposition to hair loss may be protected. However, estrogen levels decrease at menopause, which is when many women first notice hair loss.
- Female-pattern baldness is permanent.
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