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Fungal infections of the toenails (onychomycosis) affects about 7-8% of the North American population and is primarily a condition of adults. The prevalence of the onychomycosis in adults is approximately 30 times that seen in children. It may cause pain or discomfort and affect mobility as well as other activities of daily living and is therefore more than just a cosmetic issue. To date, oral griseofulvin has been the agent of choice for treating onychomycosis in children but has come into disfavour because it needs to be given for such a long time, is potentially hepatotoxic, and meta-analysis has shown a relatively poor mycological cure rate of approximately 25% with a relapse rate of 40%. The newer generation of oral antifungal agents cited in the question above, including terbinafine (Lamisil), itraconazole (Sporanox) and also fluconazole (Diflucan) have superseded the use of griseofulvin for the treatment of onychomycosis in adults. These agents have been used in children but because onychomycosis is so uncommon in this age group the series reported in the literature have been very small. In a recent Canadian report from Sunnybrook Hospital, Toronto seventeen children and teenagers were treated with one of the three new oral antifungal agents and these were found to be generally effective and well tolerated by the patients. There are several advantages seen with this new generation of oral antifungal agents that make them the current treatment of choice for onychomycosis. Firstly, although they are eliminated from the plasma within weeks of the end of treatment they persist for some time longer in the nail plate which may explain why the mycological cure rates (60-80%) are higher than that for griseofulvin. Secondly, the pharmacokinetics of these newer agents has enabled shortening of treatment duration which increases compliance. Thirdly, unlike griseofulvin, which is active against dermatophytes only, the newer agents are also active in vivo against Candida and some non-dermatophyte moulds. Pharmaco-economic analysis of griseofulvin, terbinafine and itraconazole show that terbinafine and itraconazole are the two most cost effective treatments (with no significant differences between these latter two agents). However, recent reports in the literature have indicated a note of caution with the widespread use of these newer anti-fungal agents, because with the increasing use of these drugs more severe reactions are now being reported than have previously been documented. With oral terbinafine adverse affects may be as common as 10%. Many of these side effects are cutaneous and may be serious and potentially fatal such as erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis. Terbinafine may also precipitate or aggravate psoriasis. Based on current available data it is probable that the new generation of oral antifungal agents will supersede griseofulvin as the preferred treatment for onychomycosis in children as has happened in adults. At this time it would seem more prudent to refer these children to specialists for treatment, since they have more experience with these newer agents than most practitioners. One last note; since recurrence of onychomycosis still occurs in a high proportion of treated patients, other strategies should be used in conjunction with oral medications. These include avoidance or foot protection when using facilities with a high level of dermatophyte contamination such as swimming pools, showers, changing facilities and also by discarding old shoes and sneakers that may have a high density of fungal spores. References: Jupta A K, Sibbald RG, Lynde CW et al Onychomycosis in children: Prevalence and treatment strategies. J Am Acad Derm 36:395, 1997 Wilson, N J E and White SI, Oral antifungal agents for onychomycosis Lancet 351:1516, 1998
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