A fixed dose combination of ofloxacin and ornidazole induced fixed drug eruptions

Fixed drug eruptions (FDEs) may account for 16-21% of all cutaneous drug eruptions. Recent research suggests a cell-mediated process that initiates both the active and quiescent lesions. The major categories of causative agents of fixed drug eruption include antibiotics, antiepileptics, nonsteroidal anti-inflammatory agents, sildenafil, and phenothiazines, although numerous other agents and certain foods such as cashews and licorice have also been reported as causative agents. A 38 year old male presented to the dermatology OPD with hyperpigmented and erythematous macular eruptions on the neck, chest, right arm, left scapular region, left wrist and left knee. The eruptions were associated with burning sensation and itching. He informed having taken medications for gastroenteritis the night before. The medications were Ofloxacin and Ornidazole (FDC), Omeprazole and Domperidone (FDC) and Paracetamol. He gave a history of a similar event, a year ago, with the same antimicrobial combination (Ofloxacin and Ornidazole), although the macular eruptions were restricted to the neck, arm and knee with bleb formation and severe burning sensation. Since the macular eruptions reoccurred, although with extra regions being affected, a diagnosis of FDEs was made. The most probable cause for these FDEs seems to be FDC of Ofloxacin and Ornidazole, because the patient gives history of taking Omeprazole and Paracetamol before without any FDEs. According to Naranjo’s Adverse Drug Reaction Probability Scale, the FDC of Ofloxacin and Ornidazole is a definite cause for the FDEs. (Score = 9)