Toxic Epidermal Necrolysis Secondary to Metronidazole.

Hypersensitivity reactions occur when a host exhibits an inappropriate or exaggerated response to allergens. Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are examples of such exaggerated responses to various drugs or illnesses. Both conditions affect the skin and mucosal surfaces of the oral cavity, urethra, and conjunctiva to varying degrees. TEN involves more than 30% of the total body surface area as opposed to SJS with less than 10% involvement. Skin biopsy is considered the gold standard for diagnosis; however, obtaining appropriate clinical context at presentation with the history of a potential offending drug can help diagnose the condition in situations where skin biopsy is not feasible. Metronidazole has been rarely reported as the offending agent for TEN/SJS with only two previously reported cases in the literature. We present the third case of TEN secondary to metronidazole and discuss the potential mechanism of action of metronidazole along with its common side effects. Our case adds to the existing literature of this rare clinical presentation and highlights the importance of the judicious use of metronidazole in clinical practice.