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.

Increased risk

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.

Page last reviewed: 09/08/2016
Next review due: 09/08/2019