A Case of Lichenoid Drug Eruption due to Theophylline with a Diagnostic Challenge

Abstract

　An 87-year-old man presented with reddish and violaceous, partially annular shaped plaques on the trunk and extremities. After discontinuation of sustained-release theophylline intake, the eruption resolved. Histopathology revealed lichenoid interface dermatitis with eosinophils. Although detailed drug tests were not permitted, the patient was diagnosed with lichenoid drug eruption due to theophylline. Theophylline-induced drug eruption has been rarely reported. Interestingly, lichenoid drug eruption due to theophylline has been reported in drug combination therapy. It seems difficult to diagnose drug eruption caused by theophylline because it is not linked with a specific type of drug reaction and it is usually prescribed for a long period. Dermatologists should be reminded that theophylline prescribed for a long period can be a cause of several types of drug eruptions.