Anaphylaxis and hypersensitivity syndrome reactions in increasing severity following repeated exposure to tinidazole.

Anaphylaxis is a potentially life-threatening immunological reaction that results from the sudden release of mast-cell-de­ rived and basophil-derived mediators into the circulatory sys­ tem. Hypersensitivity syndrome reactions (HSR) include cu­ taneous eruptions like erythema multiforme and StevenJohnson syndrome, and are commonly induced by drugs. Ery­ thema multiforme (EM) is an acute, usually self-limiting mu­ cocutaneous disorder characterised by unique iritis or target lesions such as macules, papules, vesicles and bullae. Severe erythema multiforme with predominantly extensive bullous eruption of the skin and mucous membrane, sudden onset, high fever and prostration is termed Stevens Johnson syndrome. We report here an interesting case of a 30-year-old male who developed erythema multiforme, laryngeal oedema, anaphy­ laxis and Stevens-Johnson syndrome following repeated expo­ sure to tinidazole. The patient presented with diarrhoea and was prescribed a combination of norfloxacin 400 mg and tinidazole 500 mg. After ingesting a few tablets, he developed dull red erythematous oral mucosal lesions over a period of few days and stopped the treatment on his own. The lesions were thought to be coincidental to drug intake and a probable diagnosis of drug-induced adverse dermatological reaction was not considered at that period of time.