Cellulitis and cellulite are two completely different conditions. 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.
Some types of bacteria are naturally present on the skin and do not normally cause any harm. However, if they go deep into the skin, they can cause an infection.
They generally enter through cuts, grazes, or bites. People with pre-existing skin conditions such eczema or psoriasis may have a higher risk of developing cellulitis.
This article covers the causes, symptoms, and treatments of cellulitis. We will also explain the risk factors and any potential complications.
Fast facts on cellulitis
Here are some key points about cellulitis. More detail and supporting information is in the main article.
- Cellulitis can occur when bacteria enters the deep layers of skin through a wound or sore
- The legs are most commonly affected
- Risk factors include a reduced immune response and obesity
- Diagnosis of cellulitis is relatively easy from observing external symptoms
- Cellulitis nearly always responds rapidly to antibiotics
Causes of cellulitis
Cellulitis is an infection of the deeper layers of the skin.
Streptococci and staphylococci groups are commonly found on the surface of the skin and cause no harm, however, if they enter the skin they can cause infection.
For the bacteria to access the deeper skin layers, they need a route. A break in the skin can be caused by:
Some people develop cellulitis without being able to identify a break in the skin.
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 might also experience a fever, chills, nausea, and shivering.
Swollen lymph glands - these may become tender. If the cellulitis has affected the patient's leg, the lymph glands in the groin may be swollen or tender.
Risk factors for cellulitis
- People with leg swelling (edema) - 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 can be weaker, or they may 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 encourages rapid progression if the infection enters the bloodstream.
- People with blood circulation problems - if a person has poor circulation they are more likely to develop skin infections.
- People with other skin infections - chicken pox and shingles cause skin blisters. If the blisters break, they become ideal routes for bacteria to get into the skin.
- People with lymphedema - these individuals 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 with 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.
Diagnosis of cellulitis
Diagnosis is usually fairly straightforward and does not generally require any complicated tests. A doctor will examine the patient and assess the symptoms. Although most cases of cellulitis are caused by streptococci and staphylococci, other medical problems like Lyme disease may look like cellulitis, so it is important to have good follow-up with a doctor after diagnosis.
The doctor may take a swab (sample) if there is an open wound. This can help them identify what type of bacteria is causing cellulitis. However, these samples are easily contaminated due to the multiple types of bacteria that live on the skin all the time.
After treatment, the patient will need to come back for a follow-up so that the doctor can confirm that the treatment has worked.
Treatments for cellulitis
The following treatments are commonly recommended for cellulitis:
Antibiotics are commonly used to treat cellulitis.
Cellulitis nearly always responds rapidly to antibiotics. Some patients experience a slight worsening of the reddening of the skin at the start of antibiotic treatment - this usually subsides within a couple of days.
Anyone who experiences fever, vomiting, or worsening symptoms after starting antibiotic treatment should contact their doctor immediately.
Many different types of antibiotics can be used to treat cellulitis, depending on what type of bacteria the doctor suspects has caused the infection.
Oral antibiotics may be given if the infection is less severe, for instance, if it hasn't reached too much of the skin.
Otherwise, the medication may be administered intravenously or by injection.
There is no way to treat cellulitis at home, and this condition needs to be treated by a doctor. If someone suspects they have cellulitis, they should call their doctor right away, and:
- Drink plenty of water.
- Keep the affected area elevated, this helps reduce swelling and pain.
- Painkillers can be taken if needed - if the individual has had stomach problems, such as a peptic ulcer, they should ask their doctor what painkiller to take. If the patient has asthma, they should ask a doctor before taking a pain medication.
Treatment in hospital
Some patients with severe cellulitis may require hospital treatment, especially if the cellulitis is deteriorating, if the patient has a high fever, vomiting, fails to respond to treatment, or has recurrences of cellulitis. Most people who are treated in hospital will receive their antibiotic through a vein in their arm (intravenously, using a drip).
Complications of cellulitis
In the vast majority of cases, cellulitis treatment is effective, and the patient will have no complications. A small percentage of patients may have serious complications. The risk of complications is higher if the cellulitis is not treated.
Blood infection and sepsis
If the bacteria reach the bloodstream, the patient has a higher risk of developing sepsis. A person with sepsis may have a fever, accelerated heartbeat, rapid breathing, hypotension (low blood pressure), dizziness when standing up, reduced urine flow, and sweaty, pale, cold skin.
Anybody who suspects blood poisoning should call the emergency services immediately, as sepsis and blood infections can be fatal.
Infection moves to other regions
This is very unusual, but the bacteria that caused the cellulitis can spread to other parts of the body, including muscle, bone, or the heart valves. If this happens, the patient needs treatment immediately.
People who do not have their cellulitis treated have a higher risk of eventually having a permanent swelling in the affected area.
Although some cases of cellulitis are not preventable, there are things people can do to reduce their chances of developing it.
Treat cuts and grazes
If the skin is broken because of a cut, bite, or graze, it should be kept clean to reduce risk of infection. The cut should be covered with a Band-Aid or dressing. Keep the dressing clean and dry.
Reduce the likelihood of scratching and infecting the skin
If fingernails are short and groomed, when the skin is scratched, it is less likely to create an opening for the bacteria to enter. Keep fingernails clean.
Take good care of the skin
Use moisturizers to prevent skin from cracking if the skin is dry. Individuals with greasy skin will not need to do this. Moisturizers will not help if the skin is already infected.
Lose weight if you are obese
Obesity may raise the risk of developing cellulitis.
Protect your skin
When gardening, wear gloves and long sleeves; when reaching into prickly bushes, do not wear shorts if there is a likelihood of grazing the skin of the legs.