Tinea capitis

ABSTRACT

Tinea capitis, the most contagious of all the tineas caused by dermatophytes, has been described as a scourge of young children.¹ Children are most susceptible before puberty, and the infection develops less commonly in older age groups. Tinea capitis is caused by a variety of dermatophytes in the genera Trichophyton and Microsporum. The common etiologic agents vary from country to country and continent to continent. At present, the organisms responsible for most infections are Trichophyton tonsurans in North America; Microsporum canis in Europe, South America, Australia, Asia, North Africa and the Middle East; Trichophyton violaceum in the Indian subcontinent and parts of Europe and Africa.²

Key Words:
Tinea capitis, Trichophyton, Microsporum, Griseofulvin, fluconazole, itraconazole, terbinafine

Treatment with griseofulvin

Griseofulvin is still considered to be the treatment of choice for tinea capitis.^3,4 The absence of pivotal clinical trials comparing griseofulvin with newer antifungals such as fluconazole, itraconazole or terbinafine, may explain why regulatory authorities in North America have not approved any one of the three newer drugs for this indication. Griseofulvin is administered orally generally for a treatment period of four to six weeks. The dosage depends in part on whether microsized or ultramicrosized griseofulvin is used.⁵ Griseofulvin has shortcomings in treating some infections due to T. violaceumor T. tonsurans.⁶ Also, infections due to M. canismay respond poorly to griseofulvin. Another drawback in using griseofulvin to treat children may be its taste.³

Clinical experience with newer antifungal agents

The advantage that terbinafine, itraconazole and fluconazole have over griseofulvin is a shorter course of treatment.⁶ All three drugs are also generally safe,⁶ and are replacing griseofulvin in the treatment of other fungal skin infections. The big question with all of these newer antifungals is what is their role in infection due to the Microsporum species?⁴ There is a suspicion from early data that they are not quite as good, but this may be simply that they are much better in Trichophyton infections.⁴

Fluconazole is available in a liquid form³, but there is little data available on its efficacy in children.² One open-label, pilot study treated T. tonsurans infections in 41 children aged between two and 15 years, with 1.5, 3 or 6 mg/kg for 20 days. Twenty seven patients completed the study and, four months after discontinuation of therapy, the clinical and mycological cure rates in each group were 25%, 60% and 89% respectively.⁸

Itraconazole seems a logical agent for children that are unable to tolerate or are non-responsive to griseofulvin.² In one study which compared itraconazole to griseofulvin (for M. canis and T. violaceum, not T. tonsurans), they were roughly equivalent.³ Anecdotally, some patients do better on one and some on the other, but itraconazole may be better than griseofulvin, especially for M. canis.³ In a multicenter study in 50 patients (48≤18 years) with tinea capitis, pulse therapy with itraconazole seemed effective and safe and was associated with a high degree of compliance.⁹ As with other antifungal drugs, the results in a clinical setting may not be as good as those obtained in well monitored and controlled clinical trials. In a very recent study, 25 children with proven T. tonsurans infections were treated with itraconazole 100 mg/day and a selenium sulfide containing shampoo for four weeks. In this open-label study in a clinical setting, only 40% of children responded to therapy.¹⁰With the oral solution being available now, a dose of 5 mg/kg/ day or pulse therapy is preferable to the fixed dose used in this study. Studies are underway investigating the efficacy of different dosage regimens of itraconazole.¹³ Terbinafine This is an allylamine that is fungicidal in vitro. It is effective in tinea capitis due to endothrix species but less effective in M. canis infections. As with the triazoles, fluconazole and itraconazole, short-term therapy lasting four weeks may be effective in endothrix infections (e.g. due to T. tonsurans)¹² and recent studies suggest that even two weeks13 of treatment, instead of the usual four weeks, might be all that is required.¹³With M. canis infections, it has been suggested that longer than six weeks of treatment may be required.¹⁴

Note * Recommended by the American Academy of Pediatrics.⁷
# Some parents have trouble getting their children to take this form of griseofulvin – even when the tablets are crushed and added to pudding or jam.³

Does shampoo treatment or prophylactic use
provide any benefit?

Ketoconazole shampoo, once daily for the first week and thentwice daily for the next three to four weeks, is being considered by some as an adjunct to oral treatment.⁶ All siblings and other family members may also benefit from the use of ketoconazole shampoo.¹³Use of selenium sulfide, 1-2.5%, to decrease spore shedding may be another alternative.³

Practical therapeutic summary

• Griseofulvin is still the treatment of choice.^3,4,13 Although response rates in controlled trials are as high as 80-90%, in the clinical setting response rates may be significantly lower because of non-compliance, inadequate drug absorption, re-exposure or resistance.¹⁵
• At this time, none of the newer drugs have regulatory approval for tinea capitis but they are alternatives to griseofulvin in the case of treatment failure or adverse side effects.
• Use a shampoo such as ketoconazole or equivalent as an adjunct to oral therapy.¹³
• Discourage sharing of hats, combs etc.¹³
• All family members should be examined and should consider using ketoconazole shampoo for their scalp.¹³
• With M. canis or a zoophilic fungus, look for an animal source of infection.¹³

References

1. Greer DL. Treatment of symptom-free carriers in management of tinea capitis. Lancet 1996; 348: 350-1
2. Elewski BE. Tinea capitis. Derm Clinics 1996; 14: 23-31.
3. Frieden IJ. Personal communication, November, 1997.
4. Hay RJ. Personal communication, November, 1997.
5. AHFS 98 Drug Information. Bethseda, Maryland. American Society of Health- System Pharmacists. 1998
6. Faergermann J. Personal communication, March 1997.
7. USPDI Drug Information for the Health Care Professional. Rockville, Maryland. United States Pharmacopeial Convention. 1998.
8. Solomon BA, Collins R, Sharma R et al. Fluconazole for the treatment of tinea capitis in children. J Am Acad Dermatol 1997; 37: 274-5.
9. Gupta AK, Hofstader SLR, Summerbell RC et al. Treatment of tinea capitis with itraconazole capsule pulse therapy. Poster. AAD Meeting, Orlando, February 1998.
10. Abdel-Rahman SM, Powell DA, Nahata MC. Efficacy of itraconazole in children with Trichophyton tonsurans tinea capitis. J Am Acad Dermatol 1998; 443-446.
11. Jones TC. Overview of the use of terbinafine (Lamisil®) in children. Brit J Dermatol 1995; 132: 683-689.
12. Haroon TS, Hussain I, Aman S et al. A randomized double-blind comparative study of terbinafine for 1,2 and 4 weeks in tinea capitis. Brit J Dermatol 1996; 135: 86-88.
13. Gupta AK. Personal communication, April 1997.
14. Drados V, Lunder M. Lack of efficacy of 6-week treatment with oral terbinafine for tinea capitis due to Microsporum canis in children. Ped Dermatol 1997; 14: 46-48.
15. Abdel-Rahman SM, Nahata MC, Powell DA. Response to initial griseofulvin therapy in pediatric patients with tinea capitis. Ann Pharmacother 1997; 31: 406-10.