What Could Be Causing This Girl’s Skin Discoloration?

A 12-year-old girl presented with a chief concern of a worsening discoloring on her trunk of 6 months’ duration. Aside from the discoloration, the area was asymptomatic. She was otherwise healthy. The skin changes had made the girl self-conscious about being in a bathing suit.

What’s causing the discoloration?

A. Vitiligo

B. Morphea

C.Tinea versicolor

D.Tinea corporis

E. Pityriasis alba

(Answer and discussion on next page)

Answer: Morphea

The girl received a clinical diagnosis of morphea. Also known as localized scleroderma (although not related to scleroderma, or systemic sclerosis), morphea is a disorder characterized by excessive collagen deposition leading to thickening of the skin. Its etiology is uncertain, but morphea is thought to be an autoimmune disorder. The condition is more common in girls and women and more frequently affects children than adults.

The differential diagnosis of morphea includes vitiligo, tinea corporis, tinea versicolor, and pityriasis alba. The lesions of vitiligo, which results from the complete absence of epidermal melanocytes, are depigmented as opposed to the ivory lesions seen here. Unlike morphea, vitiligo lesions do not feel indurated. Tinea versicolor and tinea corporis typically feature scaly plaques. Pityriasis alba lesions are hypopigmented and scaly, with ill-defined margins, and are not indurated.

Many topical (eg, calcipotriene, tacrolimus) and systemic (eg, methotrexate, corticosteroids, calcitriol, cyclosporine, interferon, UV phototherapy) morphea treatments have been tried with varying degrees of success.

David L. Kaplan, MD, is a clinical assistant professor of dermatology at the School of Medicine at the University of Missouri–Kansas City and at the University of Kansas School of Medicine. He practices adult and pediatric dermatology in Overland Park, Kansas.