Cellulitis is a common skin infection caused by bacteria. It affects the middle layer of the skin (dermis) and the tissues below. Sometimes, muscle below the skin can be affected.
Alternative Names
Skin infection - bacterial; Group A streptococcus - cellulitis; Staphylococcus - cellulitis
Causes
Staphylococcus and streptococcus bacteria are the most common causes of cellulitis.
Normal skin has many types of bacteria living on it. When there is a break in the skin, these bacteria can cause a skin infection.
Culture of any fluid or material inside the affected area
A biopsy may be done if other conditions are suspected
Treatment
You will likely be prescribed antibiotics to be taken by mouth. You may be given pain medicine as well, if needed.
At home, raise the infected area higher than your heart to reduce swelling and speed up healing. Rest until your symptoms improve.
You may need to stay in a hospital if:
You are very sick (for example, you have a very high temperature, low blood pressure, or nausea and vomiting that does not go away)
You have been on antibiotics and the infection is getting worse (spreading beyond the original pen marking)
Your immune system is not working well (due to cancer, HIV, or other medical condition)
You have an infection around your eyes
You require antibiotics through a vein (IV)
Outlook (Prognosis)
Cellulitis usually goes away after taking antibiotics for 7 to 10 days. Longer treatment may be needed if cellulitis is more severe. This may occur if you have a chronic disease or your immune system is not working properly.
People with fungal infections of the feet may have cellulitis that keeps coming back, especially if you have diabetes. Cracks in the skin from the fungal infection allow the bacteria to get into the skin.
Possible Complications
The following may result if cellulitis isn't treated or treatment doesn't work:
You are being treated for cellulitis and you develop new symptoms, such as persistent fever, drowsiness, lethargy, blistering over the cellulitis, or red streaks that spread
Prevention
Protect your skin by:
Keeping your skin moist with lotions or ointments to prevent cracking
Wearing shoes that fit well and provide enough room for your feet
Learning how to trim your nails to avoid harming the skin around them
Wearing appropriate protective equipment when participating in work or sports
Whenever you have a break in the skin:
Clean the break carefully with soap and water. Apply petroleum jelly every day.
Cover with a bandage and change it every day.
Watch for redness, pain, drainage, or other signs of infection.
Gabel C, Ko L, Kroshinsky D. Cellulitis and erysipelas. In: Lebwohl MG, Heymann WR, Coulson IH, Murrell DF, eds. Treatment of Skin Disease: Comprehensive Therapeutic Strategies. 6th ed. Philadelphia, PA: Elsevier; 2022:chap 39.
Pasternack MS, Swartz MN. Cellulitis, necrotizing fasciitis, and subcutaneous tissue infections. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 93.
Review Date:
5/31/2023
Reviewed By:
Ramin Fathi, MD, FAAD, Director, Phoenix Surgical Dermatology Group, Phoenix, AZ. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.