Erythema Nodosum Masking Kawasaki Disease with an Initial Manifestation of Skin Lesions.

We report the first case demonstrating an association between Kawasaki disease (KD) and erythema nodosum (EN). A 3-year-old girl presented with EN as an initial manifestation of KD. At the initial visit, she showed high fever of 40°C, injection of the oropharynx, cervical lymphadenopathy, and red-purple cutaneous nodules, particularly on the lower limbs. She complained of severe pain in the neck and cutaneous lesions. Initially, the development of EN was attributed to Salmonella spp infection, which was detected in stool culture. However, the patient did not respond to high-dose ampicillin/sulbactam to which the Salmonella spp is sensitive. Echocardiography performed as screening for fever of unknown origin revealed medium-sized aneurysms of the left anterior descending artery. EN masked the diagnosis of KD, and the patient developed a coronary artery lesion. KD should be considered in the differential diagnosis of refractory EN in pediatric patients.