What is responsible for the asymptomatic rash on her chin?

A 40-year-old female presented with a several month history of rash on her chin, which was asymptomatic. She is otherwise healthy and has no other rashes. 

What is responsible for her rash?

A. Morphea
B. Lichen sclerosus
C. Dermatophyte infection
D. Cutaneous lupus erythematosus
E. Vitiligo 

(Answer and discussion on next page)

Answer: Cutaneous lupus erythematosus   

A biopsy confirmed the clinical impression of cutaneous lupus. This particular lesion was mostly burnt out and will only partially improve with hydroxychloroquine therapy. 

Differential diagnosis. Morphea and lichen sclerosus are not usually seen on the face. Dermatophyte infections usually are more inflammatory and scaly. Vitiligo should be more depigmented, unlike what is seen here.