Fungal infection of the nails is an increasingly recognized disease in infants and children. However, it can be difficult to distinguish clinically from other nail dystrophies. In addition, many mistakenly believe that onychomycosis does not occur in childhood. Under-recognition of this infectious disorder therefore occurs. Although many consider "nail fungus" a trivial cosmetic concern, it can lead to discomfort, risk of secondary infection, and a more significant health threat in immunocompromised or diabetic individuals. It should always be considered in the differential diagnosis of nail plate disorders in children as it is one of the more common causes.</p> <p>Here we review the latest data on prevalence of the disease, reasons for its relatively low incidence compared with adults, and important predisposing factors. It is important to confirm the clinical diagnosis of onychomycosis in children, and affected individuals should be examined for concomitant tinea pedis. As familial disease often occurs, it is important to check parents and siblings as well for onychomycosis and tinea pedis.</p> <p>Treatment of onychomycosis is challenging, and recurrence appears to be more common in children than in adults. Prolonged systemic antifungal therapy is commonly required. However, pediatric practitioners and parents alike hesitate when asked to treat young children with a systemic drug that requires laboratory monitoring and can have systemic toxicities. Due to their thinner, faster-growing nails, children are theoretically more likely to respond to topical monotherapy than adults, and therefore good candidates for topical antifungal therapy.</p> <p>The clinical data on the use of topical antifungals in pediatric onychomycosis is scarce. We review data that exist from case reports and small clinical trials. New topical antifungals are now available that afford better nail penetration and additional delivery routes to the site of infection. Pediatric trials are now on-going, and should clarify the usefulness of these agents in children.