Alopecia areata is a condition in which hair is lost from some or all areas of the body, usually from the scalp.

Because it causes bald spots on the scalp, especially in the first stages, it is sometimes called spot baldness.

In 1–2% of cases, the condition can spread to the entire scalp called Alopecia totalis or to the entire epidermis called Alopecia Universalis.

Commonly, alopecia areata involves hair loss in one or more round spots on the scalp.

TYPES OF ALOPECIA

• Hair may also be lost more diffusely over the whole scalp, in which case the condition is called diffuse alopecia areata.
• Alopecia areata monolocularis describes baldness in only one spot. It may occur anywhere on the head.
• Alopecia areata multilocularis refers to multiple areas of hair loss.
• The disease may be limited only to the beard, in which case it is called Alopecia areata barbae.
• If the patient loses all the hair on the scalp, the disease is then called Alopecia totalis.
• If all body hair, including pubic hair, is lost, the diagnosis then becomes Alopecia universalis.
• Alopecia areata multilocularis refers to multiple areas of hair loss.

Alopecia areata totalis and universalis are rare.

SIGNS AND SYMPTOMS

• Typical first symptoms of alopecia areata are small bald patches.
• The underlying skin is unscarred and looks superficially normal.
• These patches can take many shapes, but are most usually round or oval.
• Alopecia areata most often affects the scalp and beard, but may occur on any hair-bearing part of the body.
• Different skin areas can exhibit hair loss and regrowth at the same time. The disease may also go into remission for a time, or permanently. Common in children.
• The area of hair loss may tingle or be painful.
• The hair tends to fall out over a short period of time, with the loss commonly occurring more on one side of the scalp than the other.

Exclamation point hairs are often present. Exclamation point hairs are hairs that become narrower along the length of the strand closer to the base, producing a characteristic "exclamation point" appearance.

In the case of healthy hair, if you were to try to pull some out, at most a few should come out, and ripped hair should not be distributed evenly across the tugged portion of the scalp. In cases of alopecia areata hair will tend to pull out more easily along the edge of the patch where the follicles are already being attacked by the body's immune system than away from the patch where they are still healthy.

Alopecia can cause tremendous emotional and psychosocial distress in affected patients and their families.

Nails may have pitting or trachyonchia.

CAUSES

• Alopecia areata is not contagious.
• It occurs more frequently in people who have affected family members, suggesting that heredity may be a factor.
• Strong evidence that genes may increase risk for alopecia areata was found by studying families with two or more affected members.
• This study identified at least four regions in the genome that are likely to contain alopecia areata genes.
• In addition, it is slightly more likely to occur in people who have relatives with autoimmune diseases. The condition is thought to be an autoimmune disorder in which the body attacks its own hair follicles and suppresses or stops hair growth. For example, T cell Lymphocytes cluster around affected follicles, causing inflammation and subsequent hair loss.
• There are a few recorded cases of babies being born with congenital alopecia areata; however, these are not cases of autoimmune disease because an infant is born without a fully developed immune system.
• There is some evidence that alopecia affects the part of the hair follicle that is associated with hair color. Hair that has turned gray may not be affected.