Tinea treatement regime harrison
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tinea corporis cruris pedis treatment guideline topical terbinafine oral regimen
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PMID: 40053133
Tinea treatment regimen - Harrison's Principles of Internal Medicine, 22e
Treatment depends on the anatomical site. Confirm with KOH microscopy or fungal culture, especially before oral therapy.
1. Tinea corporis, cruris, and limited pedis
First line: topical antifungal
- Topical azole: clotrimazole, miconazole, ketoconazole, etc.
- Topical allylamine: terbinafine, naftifine, or butenafine.
Apply to the lesion plus a small surrounding margin, usually twice daily, and continue for 1 week after apparent clinical clearing.
- Tinea corporis / cruris: commonly 2-4 weeks, depending on the product and response.
- Tinea pedis: often needs a longer course and has frequent relapses.
Harrison's states that topical treatment is generally effective for uncomplicated tinea corporis, cruris, and limited pedis, but nystatin is inactive against dermatophytes.
Harrison's Principles of Internal Medicine, 22e, pp. 432-433.
Harrison's Principles of Internal Medicine, 22e, pp. 432-433.
2. When to use oral treatment
Use systemic therapy for:
- Tinea capitis
- Onychomycosis
- Extensive tinea corporis/cruris
- Recurrent or treatment-resistant tinea pedis/corporis
- Failure of correctly used topical treatment
- Immunocompromised patients or severe hyperkeratotic ("moccasin") tinea pedis
Harrison's lists terbinafine, itraconazole, and griseofulvin as systemic options. It notes that terbinafine has fewer drug interactions than itraconazole and is generally the preferred systemic drug for extensive dermatophyte infection.
Harrison's Principles of Internal Medicine, 22e, p. 1778-1784; p. 1767.
Harrison's Principles of Internal Medicine, 22e, p. 1778-1784; p. 1767.
Common adult regimens used clinically:
| Condition | Usual regimen |
|---|---|
| Extensive/refractory corporis or cruris | Terbinafine 250 mg orally once daily for 2 weeks, sometimes 2-4 weeks depending on response |
| Severe/refractory tinea pedis | Terbinafine 250 mg orally once daily for 2 weeks, often longer for hyperkeratotic disease |
| Tinea capitis | Oral terbinafine or griseofulvin, usually 4-8 weeks depending on organism and formulation |
| Fingernail onychomycosis | Terbinafine 250 mg once daily for 6 weeks |
| Toenail onychomycosis | Terbinafine 250 mg once daily for 12 weeks |
For oral azoles, drug interactions are important. All oral antifungals can cause hepatotoxicity. Obtain medication history, consider baseline liver tests, and avoid oral therapy in pregnancy or breastfeeding unless specialist-directed.
3. Prevent recurrence
- Keep skin folds and feet dry.
- Dry carefully between toes after bathing.
- Use loose, breathable clothing and change socks/underwear daily.
- Treat coexisting tinea pedis and onychomycosis, which commonly reinfect the groin or body.
- Do not use topical steroid alone on a suspected fungal rash. It can mask and worsen infection, producing tinea incognito.
Important distinction
Tinea versicolor is not dermatophyte tinea. Harrison's recommends topical selenium sulfide or topical azoles, generally for 2 weeks; extensive cases may receive oral itraconazole or fluconazole for 5-7 days.
Harrison's Principles of Internal Medicine, 22e, p. 1766.
Harrison's Principles of Internal Medicine, 22e, p. 1766.
Recent evidence supports topical allylamines: a 2025 systematic review found topical naftifine effective for tinea pedis, corporis, and cruris (systematic review, PMID 40053133).
Terbinafine 250 and itraconazole
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terbinafine itraconazole combined use dermatophyte infection treatment interaction liver toxicity
Do not routinely take terbinafine 250 mg and itraconazole together for ordinary tinea. They are usually alternatives, not a standard combination. Harrison's notes terbinafine generally has fewer drug interactions and is the preferred systemic option for extensive dermatophyte skin infection.
Typical adult choices for extensive or resistant tinea
- Terbinafine: 250 mg orally once daily
- Usually 2 weeks for tinea corporis/cruris
- 2-4 weeks for severe or moccasin-type tinea pedis, guided by response
OR
- Itraconazole: commonly 100 mg twice daily or 200 mg once daily
- Often 1-2 weeks for corporis/cruris, but exact duration should be clinician-directed and depends on site, organism, and local resistance.
Safety
- Confirm fungus by KOH/culture before oral drugs, especially if the rash is recurrent or not responding.
- Check baseline liver function and review all medicines.
- Itraconazole has many CYP450 drug interactions and should not be used in heart failure without specialist advice.
- Avoid either oral medicine in pregnancy. Stop and seek medical care for jaundice, dark urine, persistent nausea/vomiting, severe fatigue, or abdominal pain.
If the infection has failed terbinafine, do not simply add itraconazole yourself. A clinician should obtain fungal testing and consider resistance, especially Trichophyton indotineae. A 2025 systematic review documents emerging terbinafine-resistant dermatophyte infection (PMID 40704771).
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