Microbiology
Intravenous amphotericin B, because it binds ergosterol directly and is the fastest-acting agent for superficial dermatophyte infections when systemic therapy is desired.
Terbinafine (an allylamine) applied topically, because it inhibits squalene epoxidase early in ergosterol synthesis and concentrates in skin, providing fungicidal activity against dermatophytes.
Oral griseofulvin must be used topically in this case because it binds keratin and interferes with microtubule formation; topical application is preferred for rapid clearance of tinea pedis.
Oral flucytosine as monotherapy, because its cytosine analog mechanism selectively inhibits fungal nucleic acid synthesis making it an ideal first-line topical agent for skin infections.
