Severe Sunburn-Like Adverse Cutaneous Drug Reaction in a Patient on Treatment with Rifaximin: A Rare Case of Acute Phototoxic Drug Reaction

Abstract

This paper describes an unreported case of a rifaximin-induced phototoxic reaction in an otherwise healthy 24-year-old female (skin type: V). The patient developed malaise, chills, and facial swelling with accompanying redness and itching that began within a day of initiating treatment with rifaximin (200 mg twice daily), and progressively increased over the next 3–4 days. The patient revealed that they had been lying in the sun for hours due to the chills they were experiencing. Over the next 10 days they developed an exaggerated, acute, sunburn-like phototoxic reaction, with blistering over the exposed skin. A skin biopsy showed no evidence of vasculopathy, endothelial damage, or extravasation of red blood cells. The patient was treated successfully with oral prednisolone (30 mg per day for a week), topical mometasone furoate (0.1%) cream applied twice daily, levocetirizine (5 mg per day taken orally), zinc oxide (20.0%) cream applied every 3 hours during daytime, and strict sun avoidance. The possible pathomechanism of rifaximin-induced sunburn is also discussed here.