Background: Kawasaki disease (KD) is a self-limited febrile vasculitis with unknown etiology. Pulmonary manifestations and acute renal failure have been documented sporadically. Mycoplasma pneumoniae can lead to diverse clinical picture. Mycoplasmal infection has been proposed for the etiology of KD but was not proved.
Case Report: We report a case of KD coexistent with Mycoplasma pneumoniae infection, complicated by myocarditis and renal failure. A 12-year-old boy was admitted with high fever and maculopapular rash. He had nonpurulent conjunctival injection, redness on cheeks, erythema of oral mucosa with cracked lips, strawberry tongue and diffuse polymorphic maculopapular eruptions and bilateral crepitations of lungs. High C-reactive protein and
erythrocyte sedimentation rate were striking on laboratory work-up. He developed prerenal acute renal failure, myocarditis, pericardial and pleural effusions on right side of the thorax with normal blood pressure. The pleural fluid was exudative and chest-tube thoracostomy was placed. His microbiological investigations were all negative except Mycoplasma pneumoniae immunoglobulin M positivity. He received appropriate antibiotherapy. The patient was still febrile and KD was diagnosed because of typical concomitant characteristic features. His fever disappeared afted intravenous immunoglubulin and aspirin therapy. Typical desquamation
of hands was observed later on. Coronary arteries were not involved at follow-up. He is still without problems at the end of one-year follow-up.
Conclusions: These two diseases have been documented rarely in the same patient at the same time. The possibility of evolving Kawasaki disease should be considered in M. pneumoniae cases if the initial manifestations of infection are in favor of vasculitis.

Keywords: Mycoplasma pneumoniae