Overview of Alopecia Areata

Alopecia areata is a non-scarring inflammatory hair loss disease occurring in approximately 1-2% of both men and women of any age. There is evidence that it is an auto-immune condition, but the condition is also associated with infections (e.g., secondary syphilis and tinea capitis), stress, bug bites, nutritional deficiencies, and other disorders (e.g., asthma and psoriasis) that may be risk factors for alopecia areata.^{(30, 121-127)}

The most common first symptom is one or more well-circumscribed patches of baldness on the scalp, without any visible signs of scalp disease. Other sites on the face are also known to present initial bald patches (eyebrows, eyelashes, or beard) but occur less frequently. Another distinguishing symptom is pitting in the nails, which is seen in up to two-thirds of all cases. Occasionally patients may complain of itchiness or a burning sensation in the patch area.^(26, 121)

There are two other types of alopecia areata, differentiated by the site and extent of hair loss, but they are much rarer:^(26, 121)

• Alopecia totalis—complete scalp baldness.
• Alopecia universalis—loss of all scalp and body hair.

Over 92% of people with alopecia areata only develop one or two balding patches on the scalp. Occasionally it may present with diffuse thinning as seen in telogen effluvium type balding, or balding patterned hair loss typical of male and female hormone-related balding.^(26, 121)