Which infection affects the entire dermis and subcutaneous fat?

The selected answer, which identifies cellulitis as the infection affecting the entire dermis and subcutaneous fat, is correct. Cellulitis is a common and potentially serious bacterial skin infection that affects the deeper layers of the skin, specifically the dermis and subcutaneous tissue. The inflammation and infection in these layers can cause redness, swelling, pain, and warmth in the affected area.

Cellulitis typically arises when bacteria enter through a break in the skin, leading to widespread infection if left untreated. The condition can occur anywhere on the body but is most commonly observed on the lower legs. Its potential to spread quickly through the connective tissue means that prompt diagnosis and treatment are crucial to prevent complications.

In contrast, other conditions mentioned do not impact the dermis and subcutaneous fat to the same extent. For instance, impetigo primarily affects superficial layers of the skin and is characterized by superficial lesions that do not penetrate deeply. Necrotizing fasciitis, while severe and potentially life-threatening, usually begins in the fascia, which is a connective tissue layer, and can indeed affect deeper structures but is specifically noted for its rapid progression and severe tissue destruction. Folliculitis primarily involves the inflammation of hair follicles, affecting only the uppermost layers of the