Which statement correctly describes topical antifungal agents?

Topical antifungal agents are specifically formulated for local application to treat fungal infections on the skin or mucosal surfaces. The statement regarding their toxicity when used systemically highlights their formulation designed for localized treatment, which may not be safe or effective when absorbed into the systemic circulation. Many topical antifungals, while effective for treating dermatologic infections, can have adverse effects if administered systematically due to their potency and the way they interact with biological systems. Hence, they are typically not suitable for systemic use, which underlines their characteristic profile and usage limitations.

Other choices suggest equivalencies or broad applicability that do not reflect the specialized role of topical antifungals. For instance, not all topical antifungals are designed to be as effective as systemic agents, and their side effects, while generally fewer and milder, are not nonexistent. Additionally, they are not effective for all types of fungal infections, particularly those that are systemic or deep-seated, necessitating more potent systemic treatments.