From the Guidelines
Toenail fungus, also called onychomycosis, is a common infection that causes thickened, discolored, and brittle nails, and is typically treated with oral antifungal medications like terbinafine (250 mg daily for 6-12 weeks) or itraconazole (200 mg daily for 12 weeks) 1.
Causes and Treatment
Onychomycosis is caused by dermatophytes, which thrive in warm, moist environments, and the infection often starts at the nail's free edge and spreads deeper 1. Treatment can be challenging because the nail provides a protective barrier for the fungus. Oral medications are generally more effective as they can reach the infection through the bloodstream.
Prevention of Recurrence
To prevent recurrence, it is essential to:
- Keep feet clean and dry
- Wear breathable shoes and moisture-wicking socks
- Use antifungal foot powder
- Avoid walking barefoot in public areas
- Discard old and mouldy footwear or eliminate fungal elements by putting naphthalene mothballs in the shoes and then leaving them enclosed within a tightly tied plastic bag for a minimum of 3 days 1.
Treatment Failure or Relapse
Onychomycosis has often been associated with high recurrence rates (40–70%), and many patients have a long history of disease recurrence 1. The term ‘recurrence’ suggests both relapse and reinfection. In treatment relapse, infection is not completely cured and returns. This implies treatment failure. In reinfection the ailment is completely cured and is followed by a new infection by the same or a different organism.
Topical Treatments
For mild cases, topical treatments such as ciclopirox nail lacquer can be applied daily for up to 48 weeks 1. Over-the-counter options like tea tree oil or snakeroot extract may also help, but are less effective than prescription treatments.
Surgical and Laser Treatments
Surgical avulsion followed by topical antifungal therapy would seem a logical approach for single-nail onychomycosis, but results from a randomized controlled trial were disappointing 1. Newer devices such as near infrared diode at 870 and 930 nm, and millisecond 1064-nm neodymium-doped yttrium aluminium garnet lasers are showing promising results in the treatment of onychomycosis, but recommendations cannot be made at this stage 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) In a second toenail study of dermatophytic onychomycosis, in which non-dermatophytes were also cultured, similar efficacy against the dermatophytes was demonstrated.
Onychomycosis of the toenail is a fungal infection that can be effectively treated with terbinafine tablets, with mycological cure rates of up to 70% and clinical cure rates of up to 38% 2.
From the Research
Definition and Prevalence of Onychomycosis
- Onychomycosis is a fungal infection of the nails, more often of the toenails, causing discoloration and/or thickening of the nail plate 3, 4, 5, 6, 7.
- It is a common condition, with an estimated overall prevalence of 3-10% in European populations 3.
- Onychomycosis occurs in 10% of the general population, 20% of persons older than 60 years, and 50% of those older than 70 years 7.
Causes and Pathogens
- Dermatophytes, especially Trichophyton rubrum and Trichophyton mentagrophytes, are the usual pathogens 3.
- Onychomycosis is predominantly caused by dermatophytes 5.
Clinical Presentation and Diagnosis
- Clinical presentation is polymorphous 5.
- Onychomycosis should be suspected in patients with discolored nails, nail plate thickening, nail separation, and foul-smelling nails 6.
- Diagnosis must be confirmed by mycological examination before initiating any therapy 5.
- Accurate diagnosis involves physical and microscopic examination and culture, and histologic evaluation using periodic acid-Schiff staining increases sensitivity for detecting infection 7.
Treatment and Management
- Medically confirmed onychomycosis should be treated 3.
- Current treatments for onychomycosis include oral antifungal agents such as terbinafine and itraconazole 3, 4, 5, 6, 7.
- Terbinafine is the drug of choice for dermatophyte onychomycosis, due to low drug interaction and good cost-effectiveness 5.
- Systemic treatments are more effective than topical treatments, and combining the two increases the cure rate 5, 6.
- Debridement of all infected keratin is the first step, reducing fungal load 5.
- Nail trimming and debridement used concurrently with pharmacologic therapy improve treatment response 6.