Facts on File Encyclopedia of Health and Medicine

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tions. Common forms of alopecia include the fol-
lowing:



  • Androgenic alopecia, or male pattern hair loss,
    in which a man’s hairline recedes from the
    temples and forehead and thins on the crown
    in a characteristic pattern that may culminate
    with a fringe of hair remaining along the sides
    and back of the head. Hair loss is permanent.
    Androgenic alopecia is hereditary and com-
    monly begins in midlife, though may begin as
    early as a man’s mid-20s. Researchers believe
    androgenic alopecia results from a combination
    of genetic predisposition and naturally declin-
    ing TESTOSTERONElevels.

  • Female pattern alopecia, in which a woman’s
    hair gradually thins on the top and sometimes
    back of her head. Hair loss is permanent.
    Researchers believe female pattern alopecia
    results from hormonal changes (loss of ESTRO-
    GENS and testosterone) that occur following
    MENOPAUSE.


•ALOPECIA AREATA, an autoimmune disorder in
which the body’s IMMUNE RESPONSEattacks clus-
ters of hair follicles, temporarily impairing their
ability to produce new cells. Alopecia areata
may affect any part of the body and occasion-
ally the entire body. Hair loss is temporary,
though may be long term.



  • Toxic alopecia, which results from exposure to
    substances that impair the ability of the hair
    follicles to generate new cells. The most com-
    mon sources of such exposure are radiation
    therapy and chemotherapy treatments for can-
    cer. Other causes include vitamin A toxicity
    and medication side effects, such as from
    retinoid preparations to treat acne. The extent
    of hair loss depends on the toxic agent, ranging
    from localized (such as with radiation therapy
    to the head) to nearly complete (such as with
    chemotherapy). Hair growth returns when the
    toxic exposure ceases.


Scarring, such as occurs as a result of BURNS,
wounds, and certain AUTOIMMUNE DISORDERS,
destroys the hair follicles so hair loss in such areas
is permanent. Conditions and circumstances that
damage but do not destroy the follicles often allow


hair growth to resume. Medical treatments that
stimulate follicle activity can accelerate the return
of hair in many such situations.

CONDITIONS ASSOCIATED WITH ALOPECIA
radiation exposure CHEMOTHERAPY
TRICHOTILLOMANIA tinea capitis
PREGNANCY MENOPAUSE
HYPOTHYROIDISM high FEVER
INFECTIONor serious illness scars from wounds or BURNS
excessive hair care and styling SUNBURNand sun exposure
AUTOIMMUNE DISORDERS DISCOID LUPUS ERYTHEMATOSUS
hormonal changes (DLE)
SYSTEMIC LUPUS MALNUTRITION
ERYTHEMATOSUS(SLE) hair coloring and styling
stress products
FOLLICULITIS

Symptoms and Diagnostic Path
Hair loss is the primary symptom of alopecia. The
pattern and rate of hair loss help determine the
nature of the underlying cause. When alopecia is
male pattern or female pattern hair loss, the doc-
tor can make the diagnosis on the basis of appear-
ance. When the cause of hair loss is uncertain, the
doctor may biopsy several sites on the scalp, both
with and without hair, for microscopic examina-
tion. A comprehensive health history and medical
examination are important to identify any poten-
tial systemic or general health causes for hair loss.
Preliminary findings determine what, if any, fur-
ther testing is necessary.
Treatment Options and Outlook
Treatment first targets any underlying condition
that may be responsible for hair loss. In many sit-
uations of alopecia related to other health condi-
tions, hair growth will resume without medical
intervention. People who are sensitive about their
appearance during the period of temporary alope-
cia may choose to wear hairpieces, hair weaves,
wigs, scarves, or hats until their hair returns. Topi-
cal products to stimulate hair growth, such as
minoxidil (Rogaine) and finasteride (Propecia),
sometimes hasten the return of hair follicle func-
tion. Such products are often the first choice of
treatment for male or female pattern hair loss as
well as many forms of nonscarring alopecia. How-
ever, hair growth typically continues only for as
long as treatment continues.

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