Atypical Nail Manifestations in Kawasaki Disease: Orange-Brown Chromonychia in a Three-Year-Old Boy

Abstract

Kawasaki disease (KD) is an acute childhood vasculitis characterized by a well-established set of clinical signs. Among the mucocutaneous manifestations, nail abnormalities are mainly observed during the convalescent phase. However, orange-brown chromonychia is a rare and early finding, still poorly documented, that could serve as an additional diagnostic clue. We report the case of a three-year-old boy admitted for persistent fever lasting seven days, presenting with the classic clinical criteria for KD, along with orange-brown chromonychia appearing on the seventh day of fever. Laboratory investigations revealed a marked inflammatory syndrome without myocardial involvement. The outcome was favorable under high-dose intravenous immunoglobulins and aspirin, with progressive resolution of the chromonychia within four weeks. A literature review identified several similar cases, mainly reported in Asia, the Americas, and Europe. To our knowledge, no cases have yet been described in Africa. Analysis of available data suggests that this nail abnormality generally occurs between the fifth and tenth days of the disease and resolves spontaneously. Its mechanism remains uncertain but may involve periungual vascular alterations. This observation highlights the importance of recognizing chromonychia as an early manifestation of KD, particularly in atypical forms.