Which type of burn primarily results in severe pain and redness?

A first-degree burn affects only the outer layer of the skin, known as the epidermis. This type of burn is characterized by symptoms such as redness, minor swelling, and significant pain. The redness is due to increased blood flow to the area as part of the body's inflammatory response to injury. The pain feels intense because there are many nerve endings in the epidermis that become irritated or inflamed when injured.

In contrast, full-thickness burns, also referred to as third-degree burns, extend through all layers of the skin and into the underlying tissues. These burns can damage nerve endings, often resulting in reduced or absent pain sensation in the burned area. While they can cause surrounding areas to be painful, the direct site of a full-thickness burn can be less painful due to nerve destruction.

Partial-thickness burns, which include second-degree burns, penetrate deeper than first-degree burns. While they can indeed be very painful and may also present with redness and blistering, the defining feature of first-degree burns is their limited depth and the primarily localized response of redness and pain.

Thus, identifying the characteristics of a first-degree burn—specifically the severe pain and redness—clarifies why this option is the correct answer.