What causes cellulitis?

Bacteria can enter through a cut, scrape, cracked skin, puncture, ulcer, surgical wound or an area affected by a fungal infection such as Athlete's Foot. The opening may be too small to notice. Once bacteria pass the skin barrier, inflammation can produce redness, heat, swelling and pain. Leg swelling, poor circulation, diabetes, eczema and a weakened immune system can make infection more likely or harder to clear; they do not mean that every area of irritated skin is cellulitis.

Clean minor breaks in the skin, protect them with a suitable dressing and avoid picking scabs. Treat ongoing cracks or fungal skin problems with professional guidance. If redness is spreading, the area is hot or tender, or you develop fever, arrange a same-day medical assessment. A clinician can distinguish cellulitis from inflammation, allergy or another skin condition.

Get urgent medical help for quickly worsening redness, marked swelling, severe pain, pus, red streaks, fever or difficulty moving a nearby joint. Emergency care is needed for confusion, faintness, extreme weakness or breathing difficulty, which can signal a serious systemic infection. Seek advice early if you have diabetes or immune suppression.

Ask what may have broken the skin barrier, whether the appearance fits cellulitis, and how to care for the affected area. Mention Athlete's Foot, eczema, leg swelling, diabetes, immune conditions and any recent wound or procedure.