What oral antifungal (antifungal medication) can be given to a 19-year-old with ringworm (tinea infection)?

Oral Antifungal Treatment for Ringworm in a 19-Year-Old

Oral terbinafine 250 mg once daily for 1-2 weeks is the recommended first-line oral antifungal treatment for a 19-year-old with ringworm (tinea corporis). 1

First-Line Treatment Options

Oral Terbinafine

• Dosage: 250 mg once daily
• Duration: 1-2 weeks for Trichophyton species infections
• Advantages:
  • Faster clinical resolution than other oral agents 1
  • High mycological cure rates (approximately 90%) 2
  • Shorter treatment duration compared to older agents like griseofulvin 3
  • FDA-approved for dermatophyte infections 4

Alternative Oral Options

Itraconazole

• Dosage: 100 mg once daily
• Duration: 2 weeks
• Considerations:
  • Similar mycological efficacy to terbinafine but may have slightly higher relapse rate 1
  • 87% mycological cure rate 1
  • Effective against both Trichophyton and Microsporum species 1

Griseofulvin

• Dosage: 15-20 mg/kg/day
• Duration: 6-8 weeks
• Considerations:
  • Primarily indicated for Microsporum species infections 1
  • Longer treatment duration compared to newer antifungals 5
  • FDA-approved specifically for dermatophyte infections including tinea corporis 6
  • Less effective than newer antifungals for most dermatophyte infections 3

Treatment Selection Considerations

Species Identification

• Determine causative organism if possible:
  • Terbinafine is most effective for Trichophyton species 1
  • Griseofulvin may be preferred for Microsporum species 1
  • Itraconazole is effective against both Trichophyton and Microsporum species 1

Extent of Infection

• For localized ringworm, topical therapy may be sufficient 1
• Consider oral therapy for:
  • Extensive or severe infection
  • Multiple lesions
  • Failure of topical treatment
  • Immunocompromised patients

Monitoring and Follow-Up

Treatment Duration

• Continue treatment for at least one week after clinical resolution 1
• The endpoint of treatment should be mycological cure, not just clinical improvement 1

Adverse Effects

• Terbinafine:
  • Generally well-tolerated with primarily gastrointestinal and dermatological side effects 1
  • Rare serious adverse reactions include Stevens-Johnson syndrome and hepatic toxicity 1, 4
  • Not recommended in patients with active or chronic liver disease 1
• Itraconazole:
  • Primarily gastrointestinal side effects, cutaneous eruptions, and occasional headache 1
  • Has potential for drug interactions 7
• Griseofulvin:
  • Generally well-tolerated with side effects including gastrointestinal disturbances and rashes 1
  • Contraindicated in lupus erythematosus, porphyria, and severe liver disease 1

Prevention of Recurrence

• Examine and treat all household members for anthropophilic infections 1
• Apply antifungal powders containing miconazole or clotrimazole to prevent reinfection 1
• Avoid sharing towels and personal items 1
• For footwear-related infections, consider using antifungal powders inside shoes and wearing cotton, absorbent socks 1

In conclusion, while several oral antifungal options exist for treating ringworm in a 19-year-old, terbinafine 250 mg daily for 1-2 weeks offers the best combination of efficacy, safety, and convenience with the shortest treatment duration.