Childhood alopecia areata-Data from the National Alopecia Areata Registry.

Childhood alopecia areata is more prevalent in girls than in boys, but boys have more extensive alopecia areata. Despite the low prevalence, congenital alopecia areata is an important differential diagnosis for neonatal hair loss. Alopecia areata runs in families, suggesting an underlying genetic background. One-quarter of the children reported at least one affected first-degree relative; 8% had more than three affected relatives.