Cellulitis: Recognising a Bacterial Skin Infection Early

What is cellulitis?

Cellulitis is a bacterial infection of the deeper layers of the skin and the tissue beneath it. Unlike many minor skin complaints, cellulitis is one infection where you should not wait and see. It can spread and, if left untreated, lead to serious complications, so prompt medical assessment matters.

How it happens

Bacteria normally living on the skin can enter through a break in the surface and cause infection. Common entry points include:

• Cuts, grazes and surgical wounds
• Insect or animal bites
• Cracked skin from conditions such as athlete's foot or eczema
• Ulcers or areas of broken, swollen skin

Most cases involve streptococcal or staphylococcal bacteria. Our overview of bacterial infections explained gives more background on how these organisms behave.

Symptoms to look for

Cellulitis usually affects the lower legs but can occur anywhere. Typical signs include:

• Skin that is red, swollen, warm and tender
• An area that grows larger or spreads over hours
• A poorly defined edge rather than a sharp border
• Pain in the affected area
• Sometimes blisters, or a fever and feeling generally unwell

On darker skin tones the redness may be harder to see, so warmth, swelling and tenderness are especially important clues.

Why cellulitis needs prompt treatment

Cellulitis does not clear up on its own and is almost always treated with antibiotics. Because the infection can spread quickly, early treatment is important. A doctor will usually prescribe a course of oral antibiotics for mild to moderate cases; penicillin-type medicines like those in our Amoxicillin guide and the wider antibiotics range are among the options a clinician may consider.

It is essential to finish the entire course even if the skin looks better, as stopping early can let the infection return and fuels antibiotic resistance explained. Tell your doctor about any antibiotic allergies before starting treatment.

Supporting your recovery

Alongside any prescribed antibiotics, the following can help:

• Rest and, where possible, raise the affected limb to reduce swelling
• Take pain relief such as paracetamol following the leaflet
• Keep to your follow-up appointments so progress can be checked
• Mark the edge of the redness with a pen so you can monitor whether it is spreading

When to seek urgent care

Contact a doctor straight away or seek emergency help if you notice:

• Redness that is spreading rapidly
• A high fever, shivering or feeling very unwell
• Increasing pain, blistering or the skin turning dark
• Confusion, a fast heartbeat, or cold, clammy skin

These can be signs the infection is becoming more serious and needs immediate attention.

Lowering your risk

Keeping skin clean and moisturised, treating conditions like athlete's foot and eczema, and cleaning and covering any cuts promptly all help reduce the chance of cellulitis. Good wound care basics are a sensible first line of defence.

General information only — not medical advice. Always read the patient information leaflet and consult a doctor or pharmacist before starting any medication.