What is the typical appearance of a fixed drug eruption?

A fixed drug eruption typically presents as an edematous plaque with a bullous center. This dermatological condition is characterized by the appearance of well-defined, dark red or brown patches that may become raised (edematous) and can develop blisters in the central area. These lesions usually recur in the same location upon re-exposure to the offending medication. The bullous formation is significant and helps differentiate this type of eruption from other dermatologic conditions.

The other descriptions do not accurately capture the defining features of a fixed drug eruption. For example, red, scaly patches without associated symptoms could indicate other skin disorders but lack the hallmark features of blistering. Flat macules may represent other conditions but do not possess the edematous or bullous characteristics specific to fixed drug eruptions. A pustular eruption primarily affects the palms and soles, which is atypical for fixed drug eruptions that can occur in various locations on the body, further distinguishing it from this type of reaction.