Cellulitis is an acute bacterial infection of the dermis and subcutaneous tissue, most often caused by Staphylococcus aureus or Streptococcus pyogenes. It usually begins at a site of minor trauma and spreads rapidly; systemic involvement may follow if treatment is delayed. Local skin changesErythema expands with irregular, slightly raised borders. The area feels warm and tight, and surrounding skin may take on a glossy, stretched appearance. Pain and tendernessA steady, throbbing ache begins soon after redness appears. Even light touch or clothing pressure becomes uncomfortable; tenderness often extends slightly beyond the visible erythema. Swelling and indurationOedema develops as capillary permeability... Learn more