Can you pick what’s causing this interdigital itch?

Xan, a 55-year-old shift worker, presents with multiple hyperpigmented brown patches and smaller papules within the web spaces of his fingers.

Test your clinical know-how by taking the quiz below. If you select the wrong answer, have another go — you can try as many times as you like!

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

Dr Timothy Cowan is a dermatology registrar, St George Hospital.

Joy Wong Lynn is a medical student at UNSW.