Cellulitis is a bacterial skin infection that affects the deeper layers of skin and underlying tissue. It is caused by bacteria, most commonly streptococcus and staphylococcus, entering through a crack or break in the skin. The infection can develop suddenly and spread quickly through the body if left untreated.

Symptoms of cellulitis include redness, swelling, and pain in the infected area of the skin. The affected skin is typically warm and tender to the touch, and may look pitted or blistered. Cellulitis can occur anywhere on the body, but it is most common on the feet and legs. Some people may also develop fever and chills.

Risk factors for cellulitis include injuries that cause a break in the skin, chronic skin conditions, chickenpox and shingles, and injection drug use. Anyone can get cellulitis, but some people are at increased risk.

Treatment for cellulitis usually involves antibiotics, which can be taken orally or intravenously depending on the severity of the infection. Other treatments may include cool, wet dressings on the infection site, keeping the area dry and clean, surgery, and elevating the affected limb if the infection is in the arm or leg. Pain medicine may also be prescribed as needed.

Complications from cellulitis are uncommon but can include serious infections such as bacteremia (blood infection), suppurative arthritis (bacterial infection in a joint), osteomyelitis (bone infection), endocarditis, extensive tissue damage, tissue death (gangrene), and the infection spreading to the blood, bones, lymph system, heart, or nervous system. To prevent cellulitis, it is recommended to use good personal hygiene and wash hands often.