An 8-year-old Hispanic girl was brought to her physician by her mother, who noticed two bald spots on the back of her daughter’s scalp while brushing her hair. The child had no itching or pain. The mother was more worried that her beautiful girl would become bald. The girl was pleased that the bald spots could be completely covered with her long hair, as she did not want anyone to see them. The child was otherwise healthy. When the mother lifted the hair in the back, two round areas of hair loss were evident (Figure 187-1). On close inspection, there was no scaling or scarring. The mother and child were reassured that alopecia areata (AA) is a condition in which the hair is likely to regrow without treatment. Neither of them wanted intralesional injections or topical therapies. During a well-child examination 1 year later, it was noted that the girl’s hair had fully regrown.1

AA is a common disorder that causes patches of hair loss without inflammation or scarring. The areas of hair loss are often round and the scalp is often very smooth at the site of hair loss.

Alopecia totalis involves the whole scalp (Figure 187-2). Alopecia universalis (AU) involves the whole scalp, head, and body.

Alopecia affects approximately 0.2% of the population at any given time with approximately 1.7% of the population experiencing an episode during their lifetime.2,3

• Men and women are equally affected.
  
• Most patients are younger than age 40 years at disease onset, with the average age being 25 to 27 years.2,4

• The etiology is unknown but experts presume that the AA spectrum of disorders is secondary to an autoimmune phenomenon involving antibodies, T cells, and cytokines.

• Previous episode of AA
  
• Family history of AA—In one study, the estimated lifetime risks were 7.1% in siblings, 7.8% in parents, and 5.7% in offspring of patients with AA.5

Clinical Features

• Sudden onset of 1 or more 1- to 4-cm areas of hair loss on the scalp (Figures 187-1 and 187-3). This can occur in the beard, eyebrows, or other areas of hair (Figure 187-4).
  
• The affected skin is smooth and may have short stubble hair growth.
  
• “Exclamation point” hairs are often noted (Figure 187-5). These hairs are characterized by proximal thinning while the distal portion remains of normal caliber.
  
• When hair begins to regrow, it often comes in as fine white hair (Figure 187-6).