Cellulitis and cellulite are two completely different things. Cellulitis is a bacterial infection of the dermis - the deep layer of skin - as well as the subcutaneous tissues (fat and soft tissue layer) that are under the skin. While cellulite is caused by fatty deposits under the skin that give it an orange peel or cottage cheese look. This article is about the bacterial infection - cellulitis.
Bacteria are present on the skin and do not generally cause any harm. However, if they go deep into the skin they can cause infection. They generally get in through cuts, grazes or bites. People with eczema or psoriasis have a higher risk of bacteria getting into the skin.
Causes of cellulitis
Bacteria, most commonly streptococci or staphylococci groups, get under the skin and cause infection. Streptococci and staphylococci groups are commonly found on the surface of the skin and cause no harm - but if they get under the skin they can. For the bacteria to get in they need a route - a break in the skin caused by:
- An ulcer
- A burn
- A bite
- A graze
- A cut
- Some skin conditions, such as eczema, athlete's foot, or psoriasis
The bacteria may also enter by some other route, such as through the blood or lymphatic system. This is most likely if no potential entry route can be identified on the skin of the patient.
Symptoms of cellulitis
Although symptoms may appear in any part of the body, the legs are most commonly affected. The affected area will become:
- Tender, inflamed
Some patients may have blisters.
The infected person may also have a fever, chills, nausea, and he/she may shiver.
Swollen lymph glands - these may become tender. If the cellulitis has affected the patient's leg the lymph glands in the groin will be tender.
Who are more susceptible to cellulitis?
- Obese people - obese people are more likely to have swelling in their legs. This raises the chances of developing cellulitis.
- People with a weakened immune system - such as patients undergoing chemotherapy or radiotherapy, those with AIDS/HIV, and very elderly people.
- People with diabetes - if the diabetes is not properly treated or controlled the patient's immune system will be weaker, he/she will have circulatory problems which can lead to skin ulcers. Poor control of blood glucose levels allows bacteria to grow faster in the affected tissue and facilitates rapid progression if the infection enters the bloodstream.
- People with blood circulation problems - if a person has poor circulation he/she is more likely to develop skin infections because the blood supply is not ideal for fighting off infections.
- People with chickenpox and shingles - chicken pox and shingles cause skin blisters. If the blisters break they become ideal routes for bacteria to get into the skin.
- People with lymphodema - people with lymphodema tend to have swollen skin which is more likely to crack. Cracks in the skin may become perfect entry routes for bacteria.
- People who have had cellulitis before - anybody who has had cellulitis has a higher risk of developing it again compared to others.
- People who inject illegal drugs - drug addicts who do not have access to a regular supply of clean needles are more likely suffer from infections deep inside the skin.
- Highly densely populated areas - there is a higher incidence of cellulitis among people who share common living quarters, such as military installations, school/college dormitories, and homeless shelters.
Diagnosis of cellulitis
Diagnosis is usually fairly straightforward and does not generally require any complicated tests. A GP (general practitioner, primary care physician) can do this. The doctor will examine the patient and assess the symptoms. The number of cases where Lyme disease has been misdiagnosed as staph- or step-induced cellulitis is growing.
It is important to discard the possibility that some other condition may have caused the symptoms, such as varicose eczema.
The doctor may take a swab (sample) if there is an open wound. This will help him/her find out what type of bacteria it is.
After treatment the patient needs to come back for a follow-up so that the doctor can confirm that the treatment has worked.
On the next page we look at the treatments for cellulitis and the ways in which the condition can be prevented. We also discuss the complications caused by cellulitis.