Orange‐brown chromonychia: A valid sign in Kawasaki disease in children of different ethnicities

Abstract

Dear Editor, Kawasaki disease (KD) is an acute systemic vasculitis that primarily affects young children worldwide. Because no specific diagnostic test is widely available, KD diagnosis is based on clinical manifestations, including acute and subacute changes in the extremities. Among the cutaneous features of KD, a variety of nail changes have been previously described.1,2 We present two patients from different countries who presented with orange‐brown chromonychia and discuss the importance of this finding. A 2 year old Mexican girl presented with fever, conjunctival erythema, cervical lymphadenopathy, generalized skin rash, cheilitis and erythema in the Bacillus Calmette–Guérin (BCG) scar. Gallbladder hydrops was documented in an ultrasound. Echocardiogram showed normal coronary arteries. The patient received iv immunoglobulin G (IVIG) at 2 g/kg, but 36 hours after she continued having fever and rash and a second dose of IVIG (2 g/ kg) was administrated. Corticosteroids were added to the regimen (prednisolone 1 mg/kg per day for 2 weeks). During a follow‐up visit 2 weeks after, brown nail lines were found in both fingers and toes (Figure 1). A Japanese 2 year old girl presented with fever, conjunctival erythema, generalized rash, edema of hands and feet, and erythema in the BCG scar. She did not respond to two doses of IVIG (2 g/ kg each) and received cyclosporin A (5 mg/kg per day for 5 days). Orange to red broad transverse lines on nails were found in both hands and toes on the 9th day of illness (Figure 1). Two months after her disease onset, nail findings were still present. She has had no coronary artery abnormalities. The most common nail changes described in the literature in KD patients are transverse leukonychia and Beau s lines. Not unique to KD, these changes are usually seen 4‐6 weeks after onset of the illness. Contrasting with this, orange‐brown chromonychia usually appears in the acute phase of the disease. Red transverse chromonychia in KD was first described in 1992.3 Its frequency has yet to be defined and no prospective studies have yet been performed. In the first description, four of 26 (15.4%) patients with KD presented this feature. Pal et al4 studied the nail beds of 40 children with KD diagnosed in India, finding that 75% of the patients had orange‐brown chromonychia appearing between days 5 and 8 after the onset of fever. On the other hand, also from India, Suri et al5 reported only four of 680 (0.6%) KD patients with orange‐brown chromonychia, but because of the retrospective nature of the study, an underreporting of the clinical sign has to be considered. The mechanism remains unclear. It may reflect a nail plate keratinization abnormality or a consequence of vasculitis, because capillaroscopy has revealed an alteration in nail fold area capillaries in the disease.6 The different colors from red to orange to brown may reflect a sequence of vascular inflammation followed by residual coloration after resolution. Both of our patients presented a refractory KD contrasting to other cases described in the literature. Chromonychia may be underrecognized in KD. Its presence could be useful in the diagnosis of the disease in doubtful cases and may represent a specific sign of the disease.