[Polymorphic eruption of pregnancy, a differential diagnosis of severe reactions to medications]

The polymorphic eruption of pregnancy (PEP) is a pathology that usually occurs in the last trimester of pregnancy and it affects around 0.5% pregnancies. So far, it has not been associated to medications, but it could mimic any severe delayed reaction to drugs.

A woman with a clinical picture that suggests PEP during the last trimester of pregnancy. She was assessed by the allergy department, where it was viewed as PEP; however, the decision was to perform skin tests: skin prick tests, intradermal tests, and skin patch tests with drugs involved; all of which showed negative results.

Severe reactions to medications are a challenge for health professionals. In acute management, the identification and suspension of the involved medication are the cornerstones of the treatment; however, many of the patients are polymedicated, which makes it difficult to identify the underlying cause. An allergy assessment is recommended as part of the optimal multidisciplinary management of each patient in order to identify the substance that is involved as the cause of the disease and, therefore, to avoid unnecessary restrictions.