A patient treated with topical mafenide acetate develops facial and neck edema. What is the most likely reason?

The development of facial and neck edema in a patient treated with topical mafenide acetate suggests a hypersensitivity reaction. Mafenide acetate is a sulfonamide derivative that can cause allergic reactions in some individuals. This type of reaction can lead to local or systemic inflammatory responses, which manifest as swelling or edema in affected areas.

In this context, facial and neck edema specifically indicates that the patient’s immune system may be reacting to the medication, potentially as a form of acute allergic response. Recognizing the signs of hypersensitivity is crucial, as it may require discontinuation of the medication and further evaluation and management of the patient's condition.

The other options relate to treatment outcomes or medication effectiveness, but they do not account for the specific nature of edema as a common result of allergic reactions to topical medications like mafenide acetate.