Cellulitis is a bacterial skin infection characterized by redness, swelling, and a feeling of heat or tenderness around the affected area. It is a condition that needs prompt medical attention. Failure to treat cellulitis can result in more serious and sometimes life-threatening infections of the blood, lymph nodes, heart and skin cells.
Cellulitis most commonly occurs when a cut in the skin is not cleaned properly. The cut can be minor, such as a scrape, or major, like a surgical incision. Bacteria, often found on normal skin cells, can then invade the lower layers of the skin and infect the subcutaneous (lowest) layer of the skin. Common bacteria that cause disease are streptococcus (strep) and staphylococcus (staph).
While cuts and punctures of the skin are the most frequent means of contracting cellulitis, other conditions may also cause this infection. People who have athlete's foot, leading to dry cracked skin, are at risk. Children and adults with chicken pox can also be vulnerable, if the pocks are scratched. Second and third degree burns, in which the skin blisters and opens, can become infected. Additionally, some spiders, like the Brown Recluse, cause immediate cellulitis when they bite.
Since cellulitis spreads quickly and can lead to more serious infections, it is important to see a doctor if you suspect you have contracted it. Along with the symptoms listed above, cellulitis may also cause fever, chills and swollen glands. One may also observe red streaks around the affected area. A doctor can properly diagnose the condition and prescribe oral antibiotics like Keflex (cephalexin), usually taken for 10-14 days. The doctor will most likely want to recheck the area to be sure the symptoms are resolving.
Untreated, cellulitis can cause multiple and very serious complications. Strep cells released into the bloodstream can result in cardiac impairment, as they grow tissue in the heart muscle, a condition known as bacterial endocarditis. Infections of the lymph nodes may need to be drained. Most seriously, gangrene and flesh-eating bacteria can develop, necessitating amputation and sometimes leading to death. At the very least, untreated cellulitis will probably result in a hospital stay and intravenous antibiotics to waylay more serious infections.
Prevention of cellulitis is fairly straightforward. For those who have noticeable cuts, wound care is essential. Recommendations include washing new cuts immediately, applying a topical antibiotic ointment, and using bandages until wounds have scabbed over. In addition, one should rewash the cut daily, unless otherwise advised by a doctor, and reapply antibiotic ointment. Children should refrain from picking at old scabs and especially pocks from chicken pox. Lastly, if you suspect you have been bitten by a poisonous spider, get medical attention immediately, as skin infection is just one of the many possible dangers from such a bite.
People with diabetes have increased risk of infections in the feet. Feet should be checked for athlete's foot regularly, and care should be taken when cutting toenails, as small cuts in the feet can be vulnerable to bacteria. Those with suppressed immune systems, either from chemotherapy or from diseases like HIV and lupus, should be especially attentive to wound care.
Through vigilance and good sense in wound care, most cases of cellulitis are preventable. However, if one suspects that despite these precautions, he or she has developed an infection, the most important thing to do is to get medical help quickly, so the effects of cellulitis can be treated before complications develop.
Most cases of cellulitis are caused by a bacterial skin infection that affects the tissues beneath the skin.
Cellulitis usually occurs when the surface of your skin is damaged. It creates an entry point for the bacteria, allowing them to attack the skin and tissue underneath. A break in the skin may be caused by a:
cut
graze
burn
animal, human or insect bite
puncture wound
skin ulcer
skin condition, such as atopic eczema (this causes the skin to become dry, red and cracked) or athlete’s foot
The break in the skin may be so small that it cannot be easily identified.
Some cases of cellulitis can develop if a wound or other break in the skin is exposed to water that is contaminated with bacteria.
A fungal infection is a much rarer cause of cellulitis. Fungal cellulitis usually only affects people with a severely weakened immune system, such as a person in the final stages of an HIV infection that is not responding to treatment.
A number of factors and other health conditions may increase your risk of developing cellulitis. These include:
being obese (excessively overweight)
having a weakened immune system
having poorly controlled diabetes
having circulation problems
having chickenpox and shingles
having lymphoedema
intravenous drug use
having previous episodes of cellulitis
These factors are briefly discussed below.
Being obese can cause swelling in your legs, which may increase your risk of developing cellulitis. Obesity is defined as being very overweight with a body mass index (BMI) of 30 or more. To check your BMI, you can use the healthy weight calculator.
Your immune system may be weakened if you have a condition such as HIV and AIDS. Having a weakened immune system makes it harder for your body to fight off infection.
A number of treatments are also known to weaken the immune system. For example:
chemotherapy – a cancer treatment that uses medication to kill cancerous cells
immunosuppressants (medications that are widely used to treat people who have had organ transplants to prevent their body rejecting the donated organ)
long-term use of corticosteroids tablets and corticosteroid creams
If you have diabetes (type 1 or type 2) that is not adequately treated or controlled, it can weaken your immune system. Poorly controlled diabetes can also affect your circulation, which can sometimes cause skin ulcers to develop. Skin ulcers are a common entry point for bacteria.
Poor circulation can increase your risk of developing skin infections in the places where your body does not have an adequate blood supply. For example, many people with diabetes have a reduced blood supply to their feet, which makes them more vulnerable to developing cellulitis.
Chickenpox and shingles often cause blisters to develop on your skin. Chickenpox (which usually only affects children) and shingles (which usually affects people aged 50 and older) are viral infections caused by the herpes varicella-zoster virus.
If the blisters that occur in chickenpox or shingles are broken or scratched, it can damage your skin and provide an entry point for bacteria.
Lymphoedema is a condition that causes fluid to build up under your skin. It may occur following surgery for some cancers. If your skin becomes very swollen it may crack, creating an entry point for bacteria.
People who inject drugs have an increased risk of developing cellulitis because poor needle hygiene, such as not sterilising the needle before and after injections, can increase the risk of infection.
If you have had a previous episode of cellulitis, your risk of having episodes in the future increases.
An estimated 20-30% of people with a previous history of cellulitis will be admitted to hospital again with another cellulitis infection. The average time between a previous and recurring cellulitis infection is three years.
Cellulitis usually begins as a small area of pain and redness on the skin. This area spreads to surrounding tissues, resulting in the typical signs of inflammation - redness, swelling, warmth, and pain. A person with cellulitis can also develop fever and/or swollen lymph nodes in the area of the infection.
If you are diagnosed with cellulitis, your recommended treatment plan will depend on your general state of health and the severity of your symptoms.
You can usually be treated at home with antibiotic tablets if:
you do not have any symptoms (such as nausea and vomiting) that would suggest the cellulitis infection has spread from your skin to other parts of the body
there are no other factors that make you more vulnerable to infection, such as having a weakened immune system or poor circulation
If this is not the case, admission to hospital is usually recommended, and you will be injected with antibiotics.
If it is thought that you are well enough to be treated at home, you will be given a seven-day course of antibiotic tablets.
The most commonly prescribed antibiotic for cellulitis is flucloxacillin, which is part of the penicillin group of antibiotics.
The most common side effects of flucloxacillin are mild digestive problems, such as an upset stomach or episodes of diarrhoea.
If you cannot take flucloxacillin because you are allergic to penicillin, an alternative antibiotic known as erythromycin can be used.
The side effects of erythromycin are usually mild and short-lived. They include:
nausea
abdominal (tummy) discomfort
vomiting
diarrhoea
If it is suspected that your cellulitis was caused by a wound in your skin being exposed to contaminated water, you will be given a combination of two different antibiotics: usually doxycycline or ciprofloxacin in combination with flucloxacillin or erythromycin.
When you first start taking the antibiotics, you may notice that your skin becomes redder. This is usually only a temporary reaction, and the redness should start to fade within 48 hours.
Contact your GP immediately if your symptoms get worse 48 hours after taking the antibiotics, or you develop additional symptoms, such as a high temperature or vomiting.
If you have cellulitis, there are things you can do at home to ease your symptoms and speed up your recovery.
Drink plenty of water to prevent dehydration. If your leg is affected by cellulitis, keep it raised. This should make you feel more comfortable and help to reduce the swelling.
If your cellulitis is causing pain or a high temperature (fever), an over-the-counter painkiller may ease your symptoms. Paracetamol and ibuprofen are suitable for cellulitis.
If you need to be admitted to hospital for treatment, you will be given antibiotics directly into your vein through an injection or a drip (known as intravenous antibiotics).
The type of antibiotics that will be used depends on the suspected cause of your infection, although a type of antibiotic known as a broad-spectrum antibiotic is often used. This type of antibiotic can kill a range of different strains of bacteria.
If your symptoms improve and you are otherwise healthy, you may be discharged after 48 hours and your treatment can switch to antibiotic tablets.
If this is not the case, a three- to four-day course of intravenous antibiotics is usually recommended before switching over to antibiotic tablets.