Korean guideline for the diagnosis and treatment of onychomycosis: Purpose and process of algorithm guideline development

Background: There have been several therapeutic guidelines for onychomycosis in different countries and advances in its diagnosis and treatment. Optimal treatment decision-making is affected by healthcare systems and cultural backgrounds of countries. Objective: The executive committee for onychomycosis guideline of the Korean Society for Medical Mycology aims to provide up-to-date practical guidelines for onychomycosis management in Koreans. Methods: The committee thoroughly reviewed relevant literature and previous guidelines. The structured algorithmic guideline was developed by experts' consensus. Results: The optimal treatments can be selected alone or in combination based on the nail and patient variables. Three major classes of treatment are available: standard (topical or oral antifungals), additional (nail removal), and alternative treatments (laser). Both topical and oral antifungals alone are appropriate for mild onychomycosis, while oral antifungals are primarily recommended for moderate-to-severe cases if not contraindicated. Combined topical and oral antifungals are recommended to increase the efficacy in moderate-to-severe cases. Additional infected nail removal is also considered for moderate-to-severe onychomycosis, which is unresponsive to standard medical treatment alone. Laser therapy can be an alternative without significant side effects when standard medical treatments cannot be applied regardless of onychomycosis severity. After treatment course completion, periodic therapeutic response monitoring and onychomycosis preventive measures should be rendered to reduce recurrence. Conclusion: The Korean consensus guideline provides evidence-based recommendations to promote good outcomes of onychomycosis. The proposed algorithm is simple and easy to comprehend, allowing clinicians to facilitate optimal treatment decision-making for onychomycosis in clinical practice.