Alopecia, commonly known as baldness, is a set of disorders which involves the state of lacking hair where it would normally grow, especially on the head. The most common form of baldness is a progressive hair-thinning condition that occurs in adult humans and other primate species. more...
Nonetheless, the severity and nature of condition can vary greatly; it ranges from male and female pattern alopecia (alopecia androgenetica), to alopecia areata, which involves the loss of some of the hair from the head, alopecia totalis, which involves the loss of all head hair, to the most extreme form, alopecia universalis, which involves the loss of all hair from the head and the body. Treatment for alopecia has limited success. The more hair lost, the less successful the treatment will be. The psychological implications of alopecia include stress, anxiety and depression, and can in many cases involve issues relating to identity change, particularly when the eyebrows and eyelashes are also lost. Hair loss is sometimes the result of chemotherapy treatment for cancer sufferers.
Male pattern baldness is thought to occur in varying forms in about 66% of adult males at some point in their lives. It is characterized by hair receding from the lateral sides of the forehead, known as "receding hairline" or "receding brow." An additional bald patch may develop on top (vertex). The trigger for this type of baldness, which is also known as androgenic alopecia, is currently believed to be 5-alpha reductase, an enzyme that converts the hormone testosterone into dihydrotestosterone (DHT), which, in genetically-prone hairs on the scalp, inhibits hair growth. Onset of hair loss sometimes begins as early as end of puberty, and is mostly genetically determined. Male pattern baldness is classified on the Hamilton-Norwood scale I-VIII.
Female pattern baldness, in which the midline parting of the hair appears broadened, is less common. It is believed to result from a decrease in estrogen, a hormone that normally counteracts the balding effect of testosterone, which normally occurs in women's blood. Female pattern baldness is being classified on the Ludwig scale I-III.
There are several other kinds of baldness. Traction alopecia is most commonly found in people with ponytails or cornrows that pull on their hair with excessive force. Wearing a hat shouldn't generally cause this, though it is a good idea to let your scalp breathe for 7 hours a day. Traumas such as chemotherapy, childbirth, major surgery, poisoning, and severe stress may cause a hair loss condition known as telogen effluvium. Some mycotic infections can cause massive hair loss. Alopecia areata is an autoimmune disorder also known as "spot baldness" that can result in hair loss ranging from just one location (Alopecia areata monolocularis) to every hair on the entire body (Alopecia areata universalis).
The term alopecia (al-oh-PEE-she-uh) is formed from the Greek αλωπηζ (alopex), meaning fox. The origin of this usage is because this animal changes its hair two times a year.
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