Onychomycosis in special populations.

Onychomycosis, a common fungal nail infection, can present unique diagnostic and therapeutic challenges in special populations including the elderly, children, individuals with diabetes, immunocompromised patients, and those with compromised organ function or psoriasis. These groups face increased susceptibility due to factors such as impaired immunity, vascular insufficiency, comorbidities, and altered nail morphology. Despite its often-benign perception, untreated onychomycosis in these populations can lead to complications, including secondary infection, ulceration, and systemic spread. Accurate diagnosis, requiring mycological confirmation, is important as clinical features may overlap with non-fungal nail disorders. Treatment must be tailored to individual risk profiles, with careful consideration of drug efficacy, safety, and potential interactions with comorbidities and polypharmacy. While systemic antifungals remain the standard for moderate-to-severe disease, their use may be limited by comorbidities, such as renal and hepatic impairment, and drug interactions. Topical antifungals such as efinaconazole, tavaborole, and ciclopirox can be considered for mild to moderate onychomycosis. This review provides an in-depth overview of the epidemiology, diagnosis, and management of onychomycosis in special populations, underscoring the importance of individualized care to improve outcomes and reduce recurrence.