Pediatric alopecia areata (AA) is more likely to affect girls, but boys are likely to have more severe types of the disorder, reported Iris Wohlmuth-Wieser, MD, of the department of dermatology, MD Anderson Cancer Center, Houston, and her associates, who conducted a large review of U.S. registry data.

Although it is the third most common dermatosis in children, there are not much data on AA in children, so the researchers used information from the National Alopecia Areata Registry, which was established in 2000. First, interested patients and parents were contacted and asked to fill out a web-based screening questionnaire. In the second phase, they were asked to fill out a more extensive survey and visit one of five U.S. sites for a clinical exam by a dermatologist.

Of the 2,218 children and teens who completed the initial questionnaire, the mean age at the time of the survey was 10 years, and their mean age of onset of AA was 6 years. The female to male ratio was 1.5:1; boys were significantly more likely to have severe types of AA (P = .009). Most patients (70%) were white, followed by mixed ethnicity (11%), Hispanic (3%), and then other ethnicities. About 3% of patients said they had a sibling with AA, 14% said that another first-degree relative had AA, and 8% said that at least three first-degree relatives had AA.

In terms of the degree of hair loss, 45% lost all scalp hair, 31% lost all body hair, and 14% lost all nails.

Concomitant diseases were reported by 47% of the responders, with atopic dermatitis, asthma, hay fever, and allergies the most common.

Of the 643 children and teens who completed a more detailed questionnaire and underwent clinical examination, 63% were female; 26% had at least one relative with AA and 8% had at least three first-degree relatives with AA. Almost 4% had congenital AA.

At the physical exam, there were data on the amount of hair loss in 617 children: Of these children, 37% had lost all scalp hair and 19% had lost up to three-quarters of their scalp hair. In 618 children (in whom information on body hair loss was obtained at the physical exam), 72% lost all or some of their body hair. Information on nails was available in 609 children; in this group, 44% had some nail involvement. More detailed information was available in 290 children; in this group, findings included pitting in 86%, dystrophy in 10%, onycholysis in 2%, ridging in 1%, and onychomycosis in 1%.

Commenting on the 25 children who presented with congenital AA, the authors wrote that this is “an extremely rare and infrequently reported form of AA.

“This is an interesting and important finding, because AA has traditionally been described as an acquired disease,” they added.

In their cohort overall, 25% had a family history of AA, with 8% having more than three first-degree relatives with AA. The researchers said that the percentage of children with AA and a positive family history ranges from 8% to 52% in the literature.

“The predominant presentation of AA types in our cohort (61.4%) was severe hair loss (76%-100% of scalp hair loss). This is comparable with a European study reporting a prevalence of 65%. Other studies on childhood AA conducted in Asian and Arab populations observed mainly mild cases,” they wrote.

Nail involvement, often reported with AA, was evident in 39% of patients who completed the questionnaire online and in 44% on physical exam. This agreed with the 26%-40% involvement reported in the literature.

There were no conflicts of interest or funding information reported.

SOURCE: Wohlmuth-Wieser I et al. Pediatr Dermatol. 2018 Jan 15. doi: 10.1111/pde.13387.

Alopecia areata has female predominance, more severe types common in boys