What is the recommended treatment for severe intertrigo using oral terbinafine (antifungal medication)?

Oral Terbinafine for Severe Intertrigo

Oral terbinafine is not recommended as first-line therapy for severe intertrigo; topical antifungal agents should be used initially, with oral terbinafine reserved for cases with confirmed dermatophyte infection that fail to respond to topical treatment. 1, 2

Treatment Algorithm for Severe Intertrigo

First-Line Treatment

• Topical antifungal agents (azoles like clotrimazole, miconazole, or polyenes like nystatin) are the recommended first-line treatment for intertrigo, especially when Candida is suspected 2
• Keeping the infected area dry is crucial for successful treatment 2
• For intertrigo in skin folds, particularly in obese and diabetic patients, topical azoles and polyenes are effective 2

When to Consider Oral Terbinafine

• Oral terbinafine (250 mg/day for adults) should be considered only when:
  • The causative organism is confirmed to be a dermatophyte (not Candida) 3, 4
  • The infection is extensive or severe 3
  • Topical treatments have failed 1
  • The patient has chronic, dry, moccasin-type infection 1

Contraindications for Oral Terbinafine

• Renal impairment (terbinafine is primarily cleared by the kidneys) 5
• Active or chronic liver disease 5
• Lupus erythematosus, porphyria 2
• Caution in patients with pre-existing liver disease due to risk of hepatic toxicity 5

Efficacy Considerations

• Terbinafine has excellent fungicidal activity against dermatophytes but variable activity against Candida species 4
• For Candida intertrigo, terbinafine has only limited and unpredictable in vitro activity 2
• For dermatophyte infections, oral terbinafine achieves mycological cure in >80% of patients 3
• The fungicidal mechanism of action of terbinafine results in improving mycological cure rates even after treatment cessation 3

Safety Profile and Monitoring

• Common side effects include:
  • Gastrointestinal disturbances (49% of reported side effects) 5
  • Dermatological events such as rash, pruritus, urticaria (23% of reported side effects) 5
• Rare but serious adverse reactions include:
  • Stevens-Johnson syndrome and toxic epidermal necrolysis 5
  • Hepatic toxicity 5
  • Taste disturbance that can potentially be permanent 5
• Baseline liver function tests and complete blood count are recommended in patients with:
  • History of heavy alcohol consumption 5
  • History of hepatitis 5
  • Hematological abnormalities 5

Special Considerations

• For non-dermatophyte intertrigo (especially Candida), alternative systemic antifungals like fluconazole or itraconazole may be more appropriate 2
• In therapy-resistant cases with confirmed fungal etiology (like Fusarium), systemic terbinafine may lead to clinical improvement but not necessarily mycological cure 6
• For mixed infections or when the causative organism is uncertain, identification of the pathogen through appropriate sampling is recommended before initiating oral antifungal therapy 3

Duration of Treatment

• For dermatophyte intertrigo requiring oral therapy, terbinafine is typically administered for 2-4 weeks 3, 7
• Treatment duration may need to be extended in resistant cases 2
• Clinical response should be assessed after 2 weeks, with consideration for alternative therapy if no improvement is seen 2