Cellulitis is usually caused by a bacterial infection.
The bacteria can infect the deeper layers of your skin if it’s broken – for example, because of an insect bite or cut, or if it’s cracked and dry.
Sometimes the break in the skin is too small to notice.
You cannot catch cellulitis from another person as it affects the deeper layers of the skin.
You’re more at risk of cellulitis if you:
- have poor circulation in your arms, legs, hands or feet – for example, because you’re overweight
- find it difficult to move around
- have a weakened immune system because of chemotherapy treatment or diabetes
- have bedsores (pressure ulcers)
- have lymphoedema, which causes fluid build-up under the skin
- inject drugs
- have a wound from surgery
- have had cellulitis before
People who are more at risk of cellulitis should treat any athlete’s foot promptly.