Which condition would most likely require a topical antiviral medication?

Topical antiviral medications are specifically designed to treat viral infections, and herpes simplex is a prominent condition that would benefit from such treatment. Herpes simplex virus (HSV) leads to infections that can manifest as cold sores or genital lesions, and using a topical antiviral can help manage symptoms, promote healing, and reduce viral shedding.

When applied to the affected area, these medications can inhibit viral replication and alleviate discomfort associated with the lesions. The targeted nature of topical antivirals is particularly effective for localized viral infections like those caused by herpes simplex.

In contrast, the other conditions listed are primarily associated with non-viral pathogens or inflammatory processes. Psoriasis is an autoimmune skin condition that requires different management strategies, typically involving topical steroids or vitamin D analogs. Fungal infections like athlete's foot necessitate antifungal treatments rather than antiviral therapies, and atopic dermatitis is an inflammatory skin condition managed with emollients and corticosteroids, not antivirals. Therefore, herpes simplex stands out as the condition that most likely requires a topical antiviral medication.