Background Kawasaki disease is an acute febrile vasculitis, with an incidence in Europe ranging from 4.9 to 15.2/100.000 children younger than 5. In developed countries, it appears to have replaced acute rheumatic fever as the leading cause of acquired heart disease in children

Case presentation We report the case of a 10 months-old male, with a history of otitis media and bronchiolitis in the previous 3 months, who presented with loss of appetite, followed by fever (38,6° Celsius) and right cervical swollen lymph node; the next day he was taken to the Emergency Room (ER) and treated by the ER physician with amoxicillin-clavulanate, but after the first dose he developed a macular erythematous rash of the trunk and face, diarrhoea, marked irritability, with the persistence of fever. Blood tests showed increased inflammatory markers and hepatocytolysis and on the second day of the fever he was admitted with high suspicion of infectious mononucleosis. His medical history also revealed that he had contact with an uncle who had recently travelled to the Middle East.

He was treated with cefuroxime and corticosteroids, with little clinical progress, persistence of fever and increase of acute-phase reactants, including C-reactive protein. During the following days, the patient gained a more complex syndrome with congestion of the conjunctive and of the lips, strawberry tongue, erythema and desquamation of the hands and soles, with daily febrile episodes. Serology tests were negative for Epstein-Barr or Cytomegalovirus infection, hepatitis A and B, Mycoplasma pneumoniae; pharyngeal swab and urine tests were also negative.

Therefore, Kawasaki disease was suspected and echocardiography was performed, which showed dilation of the left coronary artery. Diagnostic criteria for Kawasaki disease were met and in the fifth day after the onset of fever, treatment was started with intravenous immunoglobulin and high dose of aspirin with favourable clinical outcome, and regression of the coronary artery dilation.

Conclusion Approximately 25% of untreated patients suffering from Kawasaki disease develop complications, such as coronary artery aneurysms, which can lead to myocardial infarction or sudden death. The incidence on our territory is unknown. Given the development of the symptoms, with persistence of fever, it is most likely that the patient should be admitted in an infectious disease ward, therefore a continuous awareness for the Kawasaki disease diagnosis is very important. The fact that our patient received immunoglobulin treatment rather early, in the 5^th day of fever, is a marker of good prognosis.