Skin infection (cellulitis)
A spreading area of red, hot, swollen skin, often on a leg, sometimes with fever. Needs medical assessment.
How long does a course usually last?
Usually 5–7 days, sometimes longer if slow to respond — take the full course.
Your prescriber sets the exact length for you. Finish the course you're given unless a healthcare professional tells you to stop.
Never re-use antibiotics
- Do not re-use this treatment, or take leftover or someone else's antibiotics, unless a healthcare professional has expressly told you to.
- The right antibiotic, dose and length depend on your current infection, which can be different from last time.
- Re-using antibiotics can be ineffective, cause side effects, and drives antibiotic resistance. Return leftovers to any pharmacy for safe disposal.
What the guidance says
NICE recommends prompt antibiotic treatment for cellulitis because the infection can spread. A line drawn around the redness helps monitor whether it is settling. Seek urgent help if the redness spreads quickly, or you feel very unwell or confused.
Based on NICE guidance — always follow your own prescriber's advice.
Antibiotics sometimes prescribed
When to seek help
If you are getting worse, develop a high fever, feel confused or breathless, or your symptoms are not improving as expected, contact your doctor or call NHS 111. See the warning signs page.