Tinea Management

General Principles

• Topical therapy is adequate for most limited, non-hair-bearing skin infections.
• Oral (systemic) therapy is required when: hair follicles are involved (capitis, barbae), disease is widespread, or topical treatment has failed.
• Avoid combination antifungal/corticosteroid products (e.g., clotrimazole/betamethasone) — they frequently cause widespread tinea, tinea incognita, and fungal folliculitis.
• Always treat concurrent tinea pedis and onychomycosis to prevent relapse/autoinoculation.
• KOH microscopy confirms diagnosis before committing to systemic agents.

By Site

Tinea Capitis (Scalp)

• Must be treated systemically — topical agents cannot penetrate the follicle.
• Empiric oral therapy can begin while awaiting mycology cultures.
• First-line oral agents:
  • Terbinafine — preferred for Trichophyton spp. (most common in US/UK); 62.5–250 mg/day for 4–8 weeks (weight-based dosing in children)
  • Griseofulvin — preferred for Microsporum spp. (most common in Europe); ultramicrosize 10–15 mg/kg/day for 6–12 weeks
  • Itraconazole — alternative: 5 mg/kg/day for 4–6 weeks
  • Fluconazole — alternative: 6 mg/kg/day for 3–6 weeks
• Adjuvant shampoos (selenium sulfide 1–2.5%, zinc pyrithione 1–2%, ketoconazole 2%, or povidone-iodine 2.5%) used 2–4× weekly for 2–4 weeks — reduces spore shedding and transmission to contacts.
• All household members should be examined; close contacts should use adjuvant shampoo.
• Kerion (boggy inflammatory mass): systemic antifungal is essential; prednisone 1–2 mg/kg/day for the first week reduces pain, swelling, and risk of scarring alopecia (no consistent evidence of improved cure rates, but symptom benefit is clear).

Tinea Corporis (Ringworm of the Body)

• Isolated glabrous skin plaques: topical therapy for 2–4 weeks is first-line.
• Effective topical agents:
  • Allylamines: terbinafine (1 week sufficient), naftifine
  • Imidazoles: clotrimazole, miconazole, econazole, ketoconazole, oxiconazole, sulconazole
  • Others: ciclopirox, tolnaftate, butenafine
  • Most applied twice daily (econazole, ketoconazole, oxiconazole, terbinafine may be once daily)
• Oral agents reserved for: widespread disease, follicular involvement (Majocchi granuloma), immunosuppression.
  • Terbinafine 250 mg/day × 2–4 weeks, or itraconazole 100–200 mg/day × 2–4 weeks
• Majocchi granuloma always requires systemic treatment (topical agents are ineffective for deep follicular infection).

Tinea Cruris (Jock Itch)

• Treatment identical to tinea corporis — topical allylamines/imidazoles for 2–4 weeks.
• Correct underlying moisture: loose-fitting clothing, zinc-based barrier creams.
• If tinea pedis is coexistent, treat both simultaneously; patients should put on socks before underwear to prevent autoinoculation.

Tinea Pedis (Athlete's Foot)

• Mild interdigital type: topical allylamine, imidazole, ciclopirox, benzylamine, tolnaftate, or undecylenic acid. Terbinafine 1% cream BID × 1 week achieves ~66% cure.
• Vesiculobullous type: topical or systemic corticosteroids may help symptom relief during the initial antifungal treatment period.
• Moccasin (hyperkeratotic) type: often requires oral therapy.
• Bacterial co-infection (maceration, malodor, purulent discharge): search with Gram stain/culture; often involves Gram-negative organisms — treat with appropriate antibacterials concurrently.
• Associated onychomycosis must be treated (with oral agents) to prevent recurrence of tinea pedis.
• Oral agents when indicated: terbinafine 250 mg/day × 2–6 weeks, or itraconazole.

Tinea Unguium / Onychomycosis (Nail)

• Systemic therapy is required for matrix involvement, or when higher cure rate/shorter duration is desired.
• First-line oral agents:
  • Terbinafine 250 mg/day: fingernails 6 weeks, toenails 12 weeks — highest cure rates, fungicidal
  • Itraconazole pulse: 200 mg BID × 1 week/month; fingernails × 2 pulses, toenails × 3 pulses
  • Itraconazole continuous: 200 mg/day × 3 months for toenails
  • Griseofulvin no longer considered standard — prolonged course, low cure rates, drug interactions
• Topical therapy (for distal/superficial white onychomycosis or contraindication to systemic):
  • Ciclopirox 8% nail lacquer, amorolfine 5% nail lacquer, efinaconazole 10% solution, tavaborole 5% solution
• Combination oral + topical may improve clearance over monotherapy.
• Mechanical debridement (trimming, nail avulsion, curettage) speeds drug delivery. For refractory cases: laser, surgical avulsion, or 40% urea chemical avulsion + antifungal.
• Concurrent tinea pedis must always be treated to reduce risk of cellulitis (especially in diabetes, chronic venous insufficiency).

Tinea Barbae (Beard Area)

• Systemic therapy required (same principle as tinea capitis — follicular involvement).
• Oral terbinafine or itraconazole for 4–8 weeks.
• Severe inflammatory type (kerion equivalent): prednisone 1–2 mg/kg/day during the first week of antifungal treatment.

Pityriasis (Tinea) Versicolor — Malassezia spp.

• Not a dermatophyte — caused by Malassezia globosa/restricta.
• Topical first-line: selenium sulfide 2.5% shampoo/lotion, zinc pyrithione, ketoconazole 2% shampoo (left on 5–10 minutes), terbinafine spray or cream.
• Oral agents for extensive or recurrent disease: itraconazole 200 mg/day × 5–7 days, or fluconazole 400 mg single dose.
• Note: Oral ketoconazole is no longer recommended for this indication due to risk of hepatotoxicity and QT prolongation.
• Pigmentary changes (hypo- or hyperpigmentation) resolve over months after successful treatment.

Oral Antifungal Reference

Emerging Resistance — Important Update ⚠️

• Trichophyton indotineae: A pan-resistant emerging species with terbinafine resistance now spreading in Europe and globally. Therapeutic outcomes are substantially worse with standard therapy. [PMID 40186426]
• Itraconazole or voriconazole may be needed for confirmed T. indotineae infections. Consider fungal culture and susceptibility testing for cases failing terbinafine. [PMID 39082800]

Prevention & General Hygiene

• Treat all household contacts/carriers (especially in tinea capitis)
• Avoid sharing combs, hats, towels, footwear
• Change socks and underwear daily; dry skin thoroughly after washing
• Treat sports equipment/mats (tinea corporis gladiatorum)
• Wearing socks before underwear prevents autoinoculation from feet to groin

Itraconazole — Adult Doses

Dermatophyte / Superficial Fungal Infections

Onychomycosis

Systemic / Invasive Infections

Candidiasis

Key Pharmacology Points

• Formulations: 100 mg capsules; 10 mg/mL oral solution (cherry-caramel flavoured)
• Capsules: taken with food (requires gastric acidity for absorption)
• Solution: taken on an empty stomach (not affected by gastric acidity)
• SUBA-itraconazole (super bioavailable): absorption not affected by food
• Half-life: ~19–22 hours at steady state (steady state reached after 13–15 days)
• Nail accumulation: forms a drug reservoir for 6–9 months after stopping

Key Adverse Effects

• GI upset, unpleasant taste (oral solution)
• Elderly triad: edema, hypertension, hyperkalemia
• Negative inotropy — avoid in heart failure / history of cardiac disease
• Rare: hepatitis, jaundice, Stevens-Johnson syndrome, peripheral neuropathy, adrenal suppression

Key Drug Interactions (CYP3A4 substrate + inhibitor)

• Drugs that ↓ absorption: H₂ blockers, PPIs (reduce gastric acidity → reduce capsule absorption)
• CYP3A4 inducers (e.g., rifampin, phenytoin): ↓ itraconazole levels
• CYP3A4 substrates: itraconazole raises levels of many co-medications — check interactions carefully (statins, calcium channel blockers, midazolam, etc.)