Cellulitis is usually caused by an infection of the tissues beneath the skin after the surface of the skin is damaged.
Cellulitis is usually caused by a bacterial infection. It occurs when bacteria get into the tissues beneath the skin.
How the infection occurs
The bacteria that cause cellulitis often live harmlessly on the skin. But if the surface of your skin is damaged, they can get into the layers underneath and cause an infection.
The break in the skin may be so small it's not noticeable.
It may be caused by:
Cellulitis isn't normally spread from person to person as the infection occurs deep within the skin and is often caused by bacteria that live on the skin's surface without causing problems.
Anyone can get cellulitis, but you're at an increased risk if:
- you're obese – you can use the healthy weight calculator to check your weight
- you have poor circulation in your arms, legs, hands or feet
- you have a weakened immune system – for example, because of HIV or chemotherapy treatment
- you have lymphoedema – a condition that causes fluid to build up under your skin
- you have poorly controlled diabetes
- you've had cellulitis before
- you use injected drugs
Ensuring the underlying health conditions mentioned above are well controlled may help reduce your risk of getting cellulitis.
- Chronic usually means a condition that continues for a long time or keeps coming back.
- Immune system
- The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.
- The liver is the largest organ in the body. Its main jobs are to secrete bile (to help digestion), detoxify the blood and change food into energy.
- Obesity is when a person has an abnormally high amount of body fat.
- Veins are blood vessels that carry blood from the rest of the body back to the heart.