Early-desquamating perineal erythema in a febrile infant: a characteristic clinical feature of Kawasaki disease

Background: The occurrence of a distinctive perineal eruption that appears early in infants with Kawasaki disease (KD), the most relevant type of febrile vasculitis of childhood, has received little attention in pediatric reports. KD diagnosis is based on clinical criteria, which can be supported by laboratory abnormalities or positive echocardiography findings: difficulty in diagnosis can be increased by incomplete or atypical presentations, but a timely diagnostic process is essential in the youngest patients who are more prone to the risk of cardiac sequelae resulting from KD. Case Presentation: In this report, we present the case of a 2-month-old infant with an unusual presentation of KD, in whom diagnosis was made despite fever remission on the fourth day of hospitalization following intravenous corticosteroid therapy to treat concomitant bronchoconstriction. The presence of early desquamating perineal erythema led to the consideration of KD diagnosis, confirmed by the echocardiographic assessment of right and left coronary artery dilatations with pericardial effusion on the fifth day of hospital stay. Conclusions: Diagnosis of KD represents a demanding challenge, mainly when the illness starts with an incomplete or nuanced presentation. An erythematous desquamating perineal rash is a valuable early clinical clue, which might facilitate a prompt diagnosis of KD. This case emphasizes that an accurate assessment of all clinical features, including perineal erythema with early tendency to desquamation, and an eventual echocardiography, are necessary in an infant displaying fever to corroborate the suspicion of KD.