Proper pathology reveals the cause of an itchy, brown rash

A 40-year-old woman presents with a pruritic rash on her upper back.

The rash had been present since childhood. Over time, it has increased in size and become brown and papular.

Topical clotrimazole and hydrocortisone have not helped. She is otherwise well, with no past history of note and takes no regular medications.

Take the quiz below, see how you fare against your peers and share your results via social media:

Professor Dedee Murrell is head of dermatology at St George Hospital, Sydney, and conjoint professor at the University of NSW, Sydney.

This article was co-authored by Dr Tabrez Sheriff, a