What could be responsible for this woman’s persistent, itchy rash on her palms and soles?

A 55-year-old female presented with a persistent itchy rash on her hands and soles that had only a partial response to potent topical steroids, such as clobetasol cream. She is otherwise healthy and went through menopause 6 years prior. She denies any new exposure history or new medications. 

What could be responsible for the rash?

A. Dyshidrosis
B. Palmar plantar pustulosis
C. Bacterial folliculitis
D. Lichen planus
E. Contact dermatitis

(Answer and discussion on next page)

Answer—Palmar plantar pustulosis

Palmar plantar pustulosis is an uncommon variant of psoriasis that is difficult to treat. Various forms of systemic treatments have been tried with varying degrees of success. 

Dyshidrosis would present as pruritic minute vesicles on the edges of the fingers and palms. Folliculitis requires follicles, which are absent on the palms and soles. Lichen planus typically would not form pustules. Contact dermatitis would not be well-circumscribed and should respond to potent steroids and only rarely would pustules be seen. ν