Know your fungi; not all antifungal treatments created equal

NEW YORK — An overview of key issues pertaining to antifungal treatment was presented by Theoklis Zaoutis, MD, MSCE, associate chief, division of infectious diseases, The Children’s Hospital of Philadelphia, at the 23rd Annual Infectious Diseases in Children Symposium held here recently.

Zaoutis addressed treatment related to three of the most common types of fungal infections in the outpatient setting. He discussed those caused by Dermatophytoses, including tinea capitis, tinea pedis, tinea cruris and tinea corporis; the Candida infections, including oropharyngeal candidiasis, candidal diaper dermatitis and vulvovaginal candidiasis; and Malassezia furfur infections, including tinea versicolor.

Dermatophytoses treatment

When diagnosing tinea capitis, Zaoutis said it is important to keep traveling in mind because the most common cause in the United States is Trichophyton tonsurans, and the most common cause in Europe is Microsporum.

“Knowing the epidemiology of tinea capitis may help you target your therapy,” he said.

Research suggests that tinea capitis can be treated with griseofulvin, terbinafine, itraconazole or fluconazole. Treatment is always systemic because topical agents do not penetrate the hair follicle, Zaoutis said.

Griseofulvin inhibits fungal mitosis and is mainly effective against dermatophytes. It is the oldest agent used for this infection; however, with the emergence of newer agents with reduced toxicity, enhanced efficacy and shorter duration of therapy, the use of griseofulvin is now limited.

Zaoutis said terbinafine is a viable alternative and preferable to griseofulvin because it is more effective, less toxic and requires a shorter course of therapy, adding that terbinafine should be the treatment of choice for Trichophyton infections. However, infections caused by Microsporum usually require a higher dosage or longer treatment course, and in this case, griseofulvin’s efficacy is superior to that of terbinafine and is less costly.

Itraconazole requires a 2-week regimen for Trichophyton infections and 6 weeks for Microsporum infections, which is comparable with griseofulvin. Zaoutis said he considers this drug difficult to give because of the adverse events caused by drug-drug interaction.

Fluconazole requires 2 to 4 weeks of treatment and also has similar efficacy to griseofulvin. This relatively safe drug offers a once weekly dosing for 8 to 12 weeks, which is good for patients who have compliance issues, Zaoutis said.

In contrast to tinea capitis, tinea pedis can be treated with topical therapy. Topical therapy with miconazole or clotrimazole can be applied once or twice daily for 1 to 4 weeks, depending on the patient’s response. Systemic therapy is combined with topical therapy to prevent recurrences, and data show that 200 mg of itraconazole twice daily for a week results in an 85% cure rate.

Zaoutis cited data indicating that ketoconazole is similar to other azoles but is rarely used anymore compared with other azoles in the treatment of tinea pedis because of its adverse events and toxicity.

Tinea cruris and tinea corporis can be treated with topical azoles or allylamines. Terbinafine is effective in children, and 2 weeks of therapy are generally required. If infections are recalcitrant or recurrent, Zaoutis said to add a course of oral therapy besides the topical therapy.

Onychomycosis cannot be treated with topical agents, he said, because they do not penetrate the nail. Terbinafine, itraconazole or fluconazole should instead be used for 3 months.

Candida treatment

When treating oropharyngeal candidiasis, Zaoutis said he recommends clotrimazole and nystatin. The alternative to topical therapy is fluconazole for moderate to severe disease, which can be administered 6 to 12 mg/day. Duration of therapy is typically 1 to 2 weeks for any of these drugs.

For candidal diaper dermatitis, Zaoutis said topical therapy such as nystatin, miconazole or clotrimazole should be applied to each diaper change or four times a day. For this infection, oral therapy should be reserved for children with frequent recurrences.

Vulvovaginal candidiasis can be treated in one dose of 150 mg, which is “very effective therapy,” Zaoutis said. Topical agents such as miconazole, clotrimazole or nystatin are effective, and data have not indicated that any of these agents are superior. Recurring infections are treated with 10 to 14 days of induction therapy with topical or oral azole, followed by fluconazole once a week for 6 months.

Malassezia furfur treatment

For tinea versicolor treatment, Zaoutis cited data that indicated topical agents are preferred, especially in children. Selenium sulfide suspension, sodium thiosulfate lotion and 3% to 6% salicylic acid should be applied once or twice daily for 2 to 4 weeks. Oral agents are reserved for infections that are recurring, and fluconazole, ketoconazole or itraconazole can be used for 7 to 10 days. The latest data indicate that relapse is common, with 60% in the first year and 80% in the second year. In patients with recurrent infections, Zaoutis said he uses topical selenium sulphide on the first and third day of the month for 6 months, which he considers the safest choice.

For more information:

• Zaoutis T. Antifungals in the Outpatient Setting. Presented at: the 23rd Annual Infectious Diseases in Children Symposium; Nov. 20-21, 2010; New York City.

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