What is the treatment for ringworm?

Ringworm Treatment

For ringworm of the body (tinea corporis) or groin (tinea cruris), apply topical terbinafine 1% cream twice daily for 2-4 weeks as first-line treatment, which achieves mycological cure rates exceeding 80%. 1

Treatment Algorithm by Location

Body and Groin Ringworm (Tinea Corporis/Cruris)

Topical therapy is first-line for body and groin infections:

• Terbinafine 1% cream applied twice daily for 2-4 weeks is the preferred topical agent with mycological cure rates >80% 1
• Clotrimazole 1% cream applied twice daily for 2-4 weeks is an alternative, with cure rates approximately 3 times higher than placebo 1, 2
• Naftifine 1% cream is also effective, achieving mycological cure rates 2.4 times higher than placebo 2

When to use oral therapy for body/groin infections:

• If topical treatment fails after 2-4 weeks 3
• For extensive or severe infections 3
• When multiple body sites are involved 3

Scalp Ringworm (Tinea Capitis)

Oral antifungal therapy is mandatory for scalp infections—topical treatment alone will fail because it cannot penetrate the hair shaft. 1

Treatment selection depends on the causative organism:

For Trichophyton species (most common):

• Terbinafine is first-line 1
  • Patients <20 kg: 62.5 mg daily for 2-4 weeks 1
  • Patients 20-40 kg: 125 mg daily for 2-4 weeks 1
  • Patients >40 kg: 250 mg daily for 2-4 weeks 1

For Microsporum species:

• Griseofulvin is first-line 1
  • Patients <50 kg: 15-20 mg/kg/day for 6-8 weeks 1
  • Patients >50 kg: 1 g daily for 6-8 weeks 1
  • Adults: 500 mg daily (can start at 750 mg-1 g daily for severe infections, then reduce to 500 mg after response) 3

Nail Ringworm (Tinea Unguium)

Oral therapy is required for nail infections:

• Griseofulvin is FDA-approved for onychomycosis 3
  • Fingernails: at least 4 months of treatment 3
  • Toenails: at least 6 months of treatment 3

Critical Treatment Principles

Continue treatment until mycological cure is achieved, not just clinical improvement:

• Clinical relapse will occur if medication is stopped before the organism is completely eradicated 3
• Confirm eradication with appropriate clinical or laboratory examination 3
• The American Academy of Dermatology emphasizes treating until mycological cure to prevent relapse 1

Diagnosis must be confirmed before treatment:

• Obtain KOH preparation, fungal culture, or nail biopsy to confirm dermatophyte infection 3
• Direct microscopic examination or culture on appropriate medium is essential 3

Common Pitfalls to Avoid

Never use topical antifungals alone for scalp ringworm—they cannot penetrate the hair shaft and will invariably fail 1

Do not stop treatment when symptoms improve—continue until mycological cure is documented to prevent relapse 1, 3

Griseofulvin is ineffective against:

• Candida infections 3
• Bacterial infections 3
• Tinea versicolor 3
• Other non-dermatophyte fungal infections 3

Terbinafine taken orally is ineffective for pityriasis versicolor 4

Adjunctive Measures

General hygiene measures are essential to control sources of infection and reinfection 3

For tinea pedis (foot ringworm), concomitant topical agents are usually required since yeasts and bacteria may be involved alongside dermatophytes, and griseofulvin will not eradicate these co-infections 3

Emerging Resistance Concerns

Terbinafine resistance is increasing, particularly with Trichophyton indotineae infections:

• This species shows poor response to terbinafine due to mutations in the squalene epoxidase gene 5
• For terbinafine-resistant cases, itraconazole 200 mg/day or higher for longer duration is recommended 5
• Fluconazole and griseofulvin are generally not effective against T. indotineae 5