A Case of Fixed Drug Eruptions Induced by PL Granule and Benidipine Hydrochloride

Abstract

　The patient was a 79-year-old man who was prescribed Clarith^®, Mucodyne^® DS, Codeine phosphate powder^®, and PL Granule for his cold symptoms by a neighborhood doctor. He subsequently developed a rash 2 days later. There were reddish purple macules on the forehead and back, suggesting a fixed drug eruption. He had a history of hypertension and asthma and had been on Benidipine Hydrochloride (Coniel^®) and Allegra^® for the past 8 years. He had developed a rash after several months of taking these medications. The patch test was positive for PL Granule and Coniel^® in the areas covered by the rash. Furthermore, the patch test for drug components showed a positive result for promethazine methylenedisalicylate, a component of PL Granule, in the rash covered areas, whereas the result was negative for Coniel^®. Therefore, the patient's condition was diagnosed as fixed drug eruptions caused by PL Granule and Coniel^®. Because Coniel^® and the PL Granule component, promethazine methylenedisalicylate, did not have analogous chemical structures, it was inferred that the fixed drug eruptions were induced due to polysensitivity.