This portion of the antifungal review focuses on treatment rationale and suggestions, including special populations such as the elderly, children, and pregnant and immunocompromised individuals. In elderly individuals, the pathogen may be associated with certain comorbidities; treatment should begin with local treatments such as debridement (mechanical or chemical) and a topical. In children, the pathogen most commonly isolated is Trichophyton rubrum. Children should be examined for concomitant tinea and treatment options can begin with a chemical debridement (non-painful) and a topical, with non-responders being treated with combination therapy as in adults. It is suggested that blood tests are monitored at baseline and every 4-8 weeks in children on systemic therapy. Terbinafine is the only systemic in category B and local therapies should be the primary treatment modalities in pregnancy. Prevalence of onychomycosis is high in immunocompromised patients with higher relapse rates after treatment. The same fungal infections that are seen in healthy populations are usually represented in the immunocompromised host. There is a stepwise approach that is suggested in the treatment of onychomycosis. Before treatment, several factors should be determined, which include risk for failure and compliance issues. Strategies for therapy include monotherapy, combination therapy, supplemental therapy, and intermittent therapy. Topical monotherapy is effective in early distal nail disease and for the prevention of reinfection of the cured nail. Combination therapy is an appropriate progression of therapy for patients who failed monotherapy or are at risk for failure. Combined therapies are shown to increase cure rates. Mechanical interventions are essential in reducing fungal burdens to allow other modalities to penetrate, especially in dermatophytomas and onycholysis.