What is the recommended treatment for ringworm?

Recommended Treatment for Ringworm

For ringworm (tinea corporis/cruris), the recommended first-line treatment is topical antifungal therapy for localized infections, while oral terbinafine is recommended for extensive, severe, or resistant cases. 1

Diagnosis and Assessment

Before initiating treatment, confirm the diagnosis through:

• Visual inspection for characteristic ring-shaped, scaly, erythematous lesions
• If uncertain, obtain skin scrapings for microscopy and culture

Treatment Algorithm

Localized Tinea Corporis/Cruris (Body/Groin Ringworm)

1. First-line therapy: Topical antifungals

   • Apply twice daily for 2-4 weeks
   • Options include:
     • Azoles (clotrimazole 1%, miconazole)
     • Allylamines (terbinafine 1%)
     • Naftifine 1%

2. Treatment duration:

   • Continue for at least 1 week after clinical resolution
   • Terbinafine 1% cream requires only 1 week of treatment and is more effective than 4 weeks of clotrimazole (93.5% vs 73.1% mycological cure rate) 2

Extensive, Severe, or Resistant Cases

1. First-line oral therapy: Terbinafine

   • Adults: 250 mg daily for 2-4 weeks 1
   • Children (by weight):
     • <20 kg: 62.5 mg daily for 2-4 weeks
     • 20-40 kg: 125 mg daily for 2-4 weeks

     • 40 kg: 250 mg daily for 2-4 weeks 1

   • Short-course therapy (1 week) has shown high efficacy in tinea corporis/cruris 3

2. Alternative oral therapy (if terbinafine fails or is contraindicated):

   • Fluconazole: 50-100 mg daily or 150 mg once weekly for 2-3 weeks 4
   • Itraconazole: 100 mg daily for 2 weeks or 200 mg daily for 7 days 4

Special Considerations

For Tinea Capitis (Scalp Ringworm)

• Requires oral therapy - topical treatment alone is not recommended 1
• First-line treatment:
  • For Trichophyton species: Terbinafine (dosing by weight as above)
  • For Microsporum species: Griseofulvin (15-20 mg/kg/day for 6-8 weeks if <50 kg; 1 g/day if >50 kg) 1

Treatment Failure

If initial treatment fails, consider:

1. Poor adherence to treatment regimen
2. Incorrect diagnosis
3. Reinfection from contacts or fomites
4. Switch to a different antifungal class:
   • If terbinafine failed, try an azole
   • If an azole failed, try terbinafine

Additional Measures

• Maintain good hygiene and keep affected areas clean and dry
• Avoid sharing personal items (towels, clothing, combs)
• Wash clothing, bedding, and towels in hot water
• For household pets with suspected ringworm, veterinary evaluation is recommended

Monitoring and Follow-up

• Clinical improvement should be evident within 1-2 weeks
• Complete resolution may take 3-4 weeks
• Consider follow-up mycological testing for persistent cases

Cautions and Pitfalls

1. Misdiagnosis: Ringworm can be confused with eczema, psoriasis, or other dermatoses
2. Steroid use: Avoid topical steroids alone as they can worsen fungal infections (creating "tinea incognito")
3. Treatment duration: Premature discontinuation of therapy can lead to recurrence
4. Concomitant infections: Consider screening family members or close contacts for asymptomatic infection

Terbinafine has demonstrated superior efficacy compared to other antifungals for dermatophyte infections, with higher cure rates and shorter treatment duration required 2, 3.