What percentage of nail involvement is required to initiate oral antifungal treatment for onychomycosis (fungal infection of the nail)?

From the Guidelines

Oral antifungal therapy for onychomycosis should be considered when more than 50% of the nail is involved, as this indicates a more severe infection that is less likely to respond to topical treatments alone. When deciding on the treatment for onychomycosis, several factors should be considered, including the severity of the infection, the patient's medical history, and the potential side effects of the medication.

• The treatment options for onychomycosis include terbinafine and itraconazole, with terbinafine being the preferred choice due to its higher efficacy and tolerability 1.
• Terbinafine is typically prescribed at a dose of 250 mg per day for 6-16 weeks, depending on the location and severity of the infection 1.
• Itraconazole is an alternative option, which can be prescribed at a dose of 200 mg per day for 12 weeks continuously, or as pulse therapy at a dose of 400 mg per day for 1 week per month 1.
• It is essential to monitor patients during treatment for potential side effects, such as hepatotoxicity, and to perform liver function tests before starting oral therapy 1.
• The goal of treatment is to achieve a complete cure, defined as negative mycological analysis and a normal nail, which can be achieved in up to 55% of patients receiving terbinafine 1.

From the Research

Nail Involvement and Oral Antifungal Treatment

• The decision to start oral antifungal treatment for onychomycosis depends on various factors, including the severity of the disease, the infecting pathogen, and the patient's overall health 2.
• Oral antifungals are generally recommended for moderate to severe onychomycosis, while topical antifungals are recommended for mild to moderate disease 2.
• There is no specific percentage of nail involvement that determines the start of oral antifungal treatment, as the decision is based on individual patient factors and the severity of the disease.
• However, it is recommended to confirm the diagnosis of onychomycosis through mycological examination before initiating any antifungal therapy, regardless of the percentage of nail involvement 3, 2, 4.

Factors Influencing Treatment Decision

• The severity of the disease, including the extent of nail involvement and the presence of any underlying health conditions, plays a crucial role in determining the treatment approach 2, 4.
• The type of infecting pathogen, such as dermatophytes or non-dermatophytes, can also influence the choice of treatment 5, 6.
• Patient factors, including age, comorbidities, and medication history, should be considered when selecting a treatment option 2, 4.

Treatment Options

• Oral antifungals, such as terbinafine and itraconazole, are effective for moderate to severe onychomycosis 3, 2, 6.
• Topical antifungals, such as ciclopirox and efinaconazole, are recommended for mild to moderate disease 2, 4.
• Combination therapy, including oral and topical antifungals, may be considered for certain patients, such as those with severe disease or non-dermatophyte onychomycosis 5, 4.