Craters of the moon: A marker for disease severity in alopecia areata?

Abstract

In cases of severe alopecia areata in children, on close trichoscopic examination, we observed that the alopecic patch was closely packed with yellow dots of various sizes. In normal subjects, sebaceous glands of the scalp secrete sebum, but the sebaceous glands are attached to the hair follicle; hence, the sebaceous material remains attached to the hair follicle as it grows. However, in patients of alopecia areata, the sebum secreted by the sebaceous glands directly opens out onto the scalp surface as the alopecic patch is devoid of hair follicle to form a yellow dot. As it is secreted directly to the scalp surface, the sebum forms a depression on the surface of the scalp. The overview of these yellow dots is akin to the “craters of the moon.” We present a case series of severe alopecia areata wherein extensive yellow dots on trichoscopy resembled the “craters of the moon” and propose the term “craters of the moon” for yellow dots in severe alopecia areata.

Keywords

• Craters of the moon
• sebum
• severe alopecia areata
• trichoscopy
• yellow dots