Can you identify this asymptomatic reticular eruption?

DAVID L. KAPLAN, MD — Series Editor — University of Missouri Kansas City, University of Kansas

Case 1:

A 43-year-old woman with chronic hip pain presents with an asymptomatic eruption on the hip of several months' duration. She has been using a heating pad at night for pain relief because NSAIDs have not been effective.

What is the likely cause of the eruption?

            A. Livedo reticularis.

            B. Confluent and reticulated papillomatosis.

            C. Erythema ab igne.

            D. Contact dermatitis.

            E. Psoriasis.



Case 1: Erythema ab igne
The patient has erythema ab igne, C, a condition that is associated with long-term application of heat. The pattern follows the reticular blood vessels; the heat causes mild inflammation, which results in erythema and pigmentation. Discontinuation of heat application usually results in cosmetic improvement.

Livedo reticularis is symmetric. Confluent and reticulated papillomatosis occurs on the trunk and produces scale. Contact dermatitis and psoriasis both produce itching.