What is the treatment for total dystrophic onychomycosis (TDON) with 100% nail plate involvement?

From the Guidelines

For onychomycosis with 100% nail involvement, terbinafine should be considered as the first choice of treatment due to its higher efficacy and tolerability. This is based on the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1. The recommended dose of terbinafine is 250 mg per day for 12–16 weeks in toenail infection.

Key Points to Consider

• Terbinafine has been shown to be more effective than itraconazole in dermatophyte onychomycosis, with higher efficacy rates and lower relapse rates 1.
• Itraconazole is an alternative option, licensed at a dose of 200 mg per day for 12 weeks continuously, or alternatively as pulse therapy at a dose of 400 mg per day for 1 week per month 1.
• Patients should be re-evaluated 3–6 months after treatment initiation and further treatment should be given if the disease persists 1.
• It is essential to confirm the diagnosis with nail clippings for fungal culture or KOH preparation before starting treatment.
• Monitoring liver function tests before and during therapy with oral antifungals is crucial.
• Complete cure takes time as the nail must grow out fully, which may take 12-18 months for toenails.
• Adjunctive measures include keeping nails trimmed, wearing breathable footwear, using antifungal powders in shoes, and treating any concurrent tinea pedis.

Treatment Outcomes

• A multicentre, randomized trial involving 508 subjects demonstrated complete cure in 55% of patients receiving 16 weeks of continuous terbinafine, compared to 26% of patients receiving pulsed itraconazole 1.
• The long-term effectiveness of treatment during a 5-year blinded prospective follow-up study showed mycological cure without a second therapeutic intervention in 46% of terbinafine-treated patients, compared to 13% of itraconazole-treated patients 1.

From the FDA Drug Label

The efficacy of terbinafine tablets in the treatment of onychomycosis is illustrated by the response of patients with toenail and/or fingernail infections who participated in three US/Canadian placebo-controlled clinical trials Results of the first toenail study, as assessed at week 48 (12 weeks of treatment with 36 weeks follow-up after completion of therapy), demonstrated mycological cure, defined as simultaneous occurrence of negative KOH plus negative culture, in 70% of patients Fifty-nine percent (59%) of patients experienced effective treatment (mycological cure plus 0% nail involvement or >5mm of new unaffected nail growth); 38% of patients demonstrated mycological cure plus clinical cure (0% nail involvement)

The treatment for onychomycosis with 100% nail involvement is not directly addressed in the provided drug labels. However, based on the available information, Terbinafine (PO) can be considered for the treatment of onychomycosis, with 38% of patients demonstrating mycological cure plus clinical cure (0% nail involvement) in one of the studies 2. Ciclopirox (TOP) is indicated for mild to moderate onychomycosis without lunula involvement, but its effectiveness in cases with 100% nail involvement is not established 3. It is essential to note that the provided information does not directly support the use of these medications for onychomycosis with 100% nail involvement.

From the Research

Treatment Options for Onychomycosis with 100% Nail Involvement

• The treatment of onychomycosis with 100% nail involvement can be challenging, but several options are available, including topical and oral antifungal medications 4, 5, 6.
• A study published in 2022 found that efinaconazole topical solution was effective in treating total dystrophic onychomycosis, with significant improvement noted at the first assessment period and complete cure seen at a 30-week follow-up visit 6.
• Another study published in 2021 found that a combination of naftifine hydrochloride solution and cream, nail kit mycosan, and cytoflavin was effective in treating patients with onychomycosis with contraindications to systemic antifungal therapy, with mycological recovery noted in 72.7% of cases at the 48th week of treatment 7.
• The use of oral antifungal medications, such as terbinafine, in combination with topical treatments, such as amorolfine or ciclopirox, may also be effective in treating onychomycosis with 100% nail involvement 4, 5.
• Itraconazole pulse therapy has also been shown to be effective in treating onychomycosis, particularly in cases where the pathogen is Candida species 8.

Factors Affecting Treatment Success

• The severity of the infection, as measured by the Scoring Clinical Index for Onychomycosis (SCIO), can affect treatment success, with higher SCIO values associated with lower cure rates 5.
• The type of fungus causing the infection can also affect treatment success, with some fungi being more resistant to certain treatments than others 4, 8.
• Patient compliance with treatment and follow-up appointments is also crucial for successful treatment of onychomycosis 6, 7.

Future Directions

• Further research is needed to determine the most effective treatment options for onychomycosis with 100% nail involvement, particularly in cases where the patient has contraindications to systemic antifungal therapy 7.
• The development of new topical and oral antifungal medications, as well as combination therapies, may also improve treatment outcomes for patients with onychomycosis 4, 5, 6.