Chronic fixed drug eruption caused by acetaminophen.

A case of chronic fixed drug eruption resembling parapsoriasis en plaques is reported, which presented with persistent, stable lesions that were present for seven months before the diagnosis was established. The patient's skin cleared totally with avoidance of acetaminophen and flared prominently with re-exposure. Distribution of the recurrence was different: some previous sites had apparently become refractory and remained clear, some involvement had recurred in the same site, and new areas of involvement had appeared, causing the eruption to "wander," as is often seen in acute fixed drug eruption due to acetaminophen.