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Hair Loss
Alternate Names : Alopecia, Baldness, Loss of Hair
Definition
Partial or complete loss of hair is called alopecia.
Pictures & Images
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Overview & Considerations
Hair loss usually develops gradually and may be patchy or diffuse (all over). Roughly 100 hairs are lost from your head every day. The average scalp contains about 100,000 hairs.
Each individual hair survives for an average of 4 1/2 years, during which time it grows about half an inch a month. Usually in its 5th year, the hair falls out and is replaced within 6 months by a new one. Genetic baldness is caused by the body's failure to produce new hairs and not by excessive hair loss.
Both men and women tend to lose hair thickness and amount as they age. Inherited or "pattern baldness" affects many more men than women. About 25% of men begin to bald by the time they are 30 years old, and about two-thirds are either bald or have a balding pattern by age 60.
Typical male pattern baldness involves a receding hairline and thinning around the crown with eventual bald spots. Ultimately, you may have only a horseshoe ring of hair around the sides. In addition to genes, male-pattern baldness seems to require the presence of the male hormone testosterone. Men who do not produce testosterone (because of genetic abnormalities or castration) do not develop this pattern of baldness.
Some women also develop a particular pattern of hair loss due to genetics, age, and male hormones that tend to increase in women after menopause. The pattern is different from that of men. Female pattern baldness involves a thinning throughout the scalp while the frontal hairline generally remains intact.
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• Definition
• Hair Loss: Overview & Considerations
• Hair Loss: Common Causes
• Hair Loss: Home Care & Treatment
• Call your Health Care Provider if
• What to Expect at your Health Care Provider's Office
• Pictures & Images
Topics that might be of interest to you Diseases & Conditions
• Alopecia Areata
• Female Pattern Baldness
• Male Pattern Baldness
• Ringworm
• Thyroid Diseases
• Tinea Capitis
• Trichotillomania
Tests & Exams
• Skin Lesion Biopsy
• Testosterone
Other Topics
• Chemotherapy
• Radiation Therapy
Review Date : 11/4/2003
Reviewed By : Jacqueline A. Hart, M.D., Department of Internal Medicine, Newton-Wellesley Hospital, Boston, Ma., and Senior Medical Editor, A.D.A.M., Inc. Previously reviewed by Michael Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network (4/15/2003).
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