Erythema ab Igne in a 55-Year-Old Woman With Arthritis

An area of mottled skin developed on the back of a 55-year-old woman who has had arthritis for several years. She often applied a heating pad to her middle and lower back for relief from arthritic pain.

Dr Reynold C. Wong of Sacramento, Calif, writes that the distinctive, reticulated pattern with hyperpigmentation is characteristic of erythema ab igne. The very frequent and long-term use of a hot pad provoked the skin disorder.

This patient followed medical advice and gave up using the heating pad. Over the course of several months, the color of the reticulated pattern faded, but some of the hyperpigmentation persisted.

Squamous cell carcinoma is a rare sequela of erythema ab igne.