A second-degree burn is classified as what type of primary skin lesion?

A second-degree burn is classified as a bulla because it involves the formation of blisters filled with fluid. This type of burn affects both the epidermis and the dermis, leading to swelling and the potential for fluid accumulation under the skin's surface, which manifests as large, raised areas known as bullae.

In contrast, a pustule is a small, inflamed blister containing pus, often seen in infections or acne, and does not specifically relate to burns. A macule is a flat, discolored area of the skin that does not involve any elevation or blistering, making it thematically unrelated to the characteristics of a second-degree burn. A patch is similar to a macule but larger, and it also does not represent the blistering characteristic of a second-degree burn. Recognizing the specific features of skin lesions helps in identifying the correct classification based on their presentation.