By Dr Ananya Mandal, MD
Cellulitis is the term given to an infection of the dermal and subcutaneous skin layers that gives rise to red, swollen and painful skin. Cellulitis can be dangerous if it is not treated promptly as it may spread further afield and even lead to septicemia, a severe infection of the blood.
Pathology and causes of cellulitis
The skin is the largest organ in the body and is comprised of three layers which include:
- The epidermis or outer layer of skin.
- The dermis or middle layer of skin where sweat glands, hair follicles and blood vessels are contained.
- The subcutis or bottom skin layer containing fat and collagen, which provides protection and regulates body temperature.
Cellulitis develops when bacteria and sometimes fungi enter the skin surface through an abrasion such as a cut or bruise. The most common bacteria to cause infection are Streptococcus or Staphylococcus aureus, bacteria that form part of the skin’s natural flora.
Some of the risk factors for cellulitis include:
- Skin wounds or burns
- Eczema which causes tiny cracks or breaks in the skin
- A weak immune system in those with diabetes or HIV infection, for example, or those receiving treatment with chemotherapy or steroids.
- Intravenous drug users
Symptoms of cellulitis
The condition causes red, hot, painful and swollen areas across affected skin. Some patients develop fever, chills and tremors. A particularly high fever along with delirium or confusion may be a sign of septicemia and should be treated as an emergency.
Treatment of cellulitis
Since cellulitis is usually caused by an infective bacteria, it is treated using antibiotics that are suitable for killing the organism. For fungal infections, antifungal agents are used.
Reviewed by Sally Robertson, BSc
Last Updated: Oct 8, 2014