Test your diagnostic skills in our regular dermatology quiz. What is the cause of these nodules, which are located on the extensor surface of the interphalangeal joints of a woman’s fingers?
A 75-year-old woman presents for a full skin examination. Multiple skin-coloured to red nodules are noted overlying the extensor surface of the distal interphalangeal joints of her right index and middle fingers as well as the proximal interphalangeal joint of her left index finger (Figure). The patient recalls these nodules being present for at least five years. They are intermittently painful but not itchy and do not ulcerate or develop blistering change. She has no similar skin changes elsewhere.