What is a deep injection of the dermis that is typically caused by streptococcus?

Cellulitis is a deep infection of the dermis and subcutaneous tissue typically caused by bacterial organisms, with streptococcus being a common culprit. It is characterized by redness, swelling, warmth, and tenderness in the affected area, often accompanied by systemic symptoms such as fever. The infection occurs when bacteria penetrate through a break in the skin, leading to inflammation and acute symptoms.

Furuncles, also known as boils, are deeper infections involving hair follicles and surrounding tissue, primarily caused by Staphylococcus bacteria rather than streptococcus. Impetigo is a superficial skin infection that is most commonly seen in children and is usually caused by staphylococcus or streptococcus, but it affects the outer layers of the skin rather than the deep dermis. Folliculitis involves inflammation of hair follicles and is usually superficial, resulting from various causes including infection or irritation but does not typically affect the deeper dermal layers like cellulitis does. Thus, cellulitis is the correct answer as it directly pertains to the deep dermal layer infection associated with streptococcus bacteria.