Tinea capitis, or ringworm of the scalp, is the most common dermatophyte infection among children in the world. Approximately 3 to 8 percent of American children are affected, and up to one third of in-house contacts are asymptomatic carriers. Tinea infections are usually spread by humans but may also be acquired from animals. Adolescent and adult infections are uncommon due to the fungistatic effect of the sebum found in older persons. The three primary dermatophytes most commonly encountered are Trichophyton tonsurans, Microsporum audouinii and Microsporum canis. Griseofulvin has long been the standard therapy for tinea capitis and is currently the only antifungal agent labeled by the U.S. Food and Drug Administration for this condition. Temple and associates reviewed the current evidence for griseofulvin as well as several other antifungal agents that have been used to treat tinea capitis. The authors used the STEP approach (safety, tolerability, effectiveness, price) in their analysis of the data.

One of the trials compared griseofulvin with ketoconazole in a randomized study of 79 children. Six percent of 46 patients receiving griseofulvin had mild elevations of hepatic transaminases that were of no clinical significance. A second study of 47 children with the same two drugs found a twofold increase in transaminases in one patient on griseofulvin. In a third double-blind study of 35 patients taking griseofulvin or itraconazole, 12 percent of the patients taking griseofulvin stopped therapy because of nausea, vomiting and abdominal pain. No problems were reported among patients taking itraconazole. Itraconazole, fluconazole and ketoconazole have not been associated with hepatotoxicity in children being treated for tinea capitis. Two studies (n = 12; n = 161) that used terbinafine in four- to six-week regimens found that 33 percent and 12 percent respectively experienced adverse effects, primarily of a gastrointestinal nature.

The randomized trial of griseofulvin and ketoconazole that involved 79 children found that all patients who took griseofulvin had significantly improved hair growth and reduction in scaling, crusting, erythema and inflammation. Six patients on ketoconazole failed treatment after 12 weeks. In a second study comparing these two agents, treatment was continued until lesions resolved and the microscopic examination of hair was negative. The median time of treatment was 108 days for ketoconazole and 60 days for griseofulvin. This study also found that 92 percent of patients on griseofulvin and 59 percent of patients on ketoconazole had sterile cultures at the final follow-up visits.

The study of oral terbinafine given for one, two and four weeks showed mycologic cure rates of 88, 62 and 100 percent, respectively. Clinical cure rates did not differ among the three groups. Another study (n = 13) used pulse-dose therapy of terbinafine with a week on and two weeks off for one to three cycles. Twelve of the 13 patients had clinical and mycologic cures.

The three studies that were cited using itraconazole for tinea capitis found the response rate to be generally poor. In one of these three, only a 50 percent cure rate occurred after four weeks of dosing at 100 mg per day.

Intralesional steroids are often used for severe cases of tinea capitis. However, there are no randomized trials to support this practice. One study of 30 children that combined steroids with griseofulvin compared with griseofulvin alone found no differences in outcomes. There is good evidence to show that the adjunctive use of topical selenium sulfide shampoo (1 or 2.5 percent) will shorten the time required to eliminate shedding of spores.

In evaluating price, griseofulvin appears to be the most costly treatment. However, the higher cost must be weighed against extra clinic visits, laboratory monitoring, managing adverse reactions and treatment failures seen with other agents.

In summary, based on current evidence, griseofulvin has the best efficacy for treating tinea capitis. Ketoconazole is effective but causes more side effects and drug interactions.