What characterizes a first degree burn?

A first-degree burn is characterized by affecting only the epidermis, which is the outermost layer of skin. This type of burn is typically caused by mild sunburns or brief contact with hot surfaces. The skin may appear red and feel painful, but it does not result in blistering or damage to deeper layers of skin, such as the dermis.

Understanding first-degree burns helps in recognizing the severity of burns. In contrast, options that mention full thickness involvement or significant blistering describe second-degree burns, which penetrate deeper into the skin layers. The mention of upper muscle layers in one of the options inaccurately extends the classification of burns into deeper tissue damage, which does not apply to first-degree burns. Thus, identifying first-degree burns as exclusively involving the epidermis is essential for appropriate care and treatment.