Skin
Blisters on the skin
Raised, fluid-filled bumps on the skin that can follow friction or burns, but also arise from skin conditions and infections — and which, when widespread or affecting the eyes, mouth or genitals, can signal a serious reaction needing emergency care.
Education and reference only. This explains the common causes of blisters on the skin and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is blisters on the skin?
A blister is a small pocket of fluid that forms within the upper layers of the skin, usually as a protective response to damage. The commonest blisters come from friction, heat or minor burns and heal on their own.
- Get urgent help: Call 999 or seek emergency care for widespread blistering with fever, or blisters affecting the eyes, mouth or genitals — this can be a severe drug or skin reaction. Seek urgent help for skin that is peeling away in sheets, or blistering with a high temperature and feeling very unwell.
- Self-care: A small blister from friction or a minor burn is usually best left intact, as the overlying skin protects the raw area beneath and reduces the risk of infection.
About blisters on the skin
A blister is a small pocket of fluid that forms within the upper layers of the skin, usually as a protective response to damage. The commonest blisters come from friction, heat or minor burns and heal on their own. When blisters appear without an obvious injury, the pattern and setting offer clues. Itchy, deep-seated blisters on the palms and sides of the fingers suggest pompholyx, while honey-coloured crusting blisters around the nose and mouth in a child suggest impetigo, a contagious bacterial infection. Viral infections cause their own patterns: clustered blisters on the lip suggest cold sores, a painful band of blisters on one side of the body suggests shingles, and crops of itchy blistering spots suggest chickenpox. A flare of eczema or a reaction where the skin touched an allergen can also blister. Most blisters are minor, but widespread blistering with fever, or blisters involving the eyes, mouth or genitals, can mean a severe skin or drug reaction and is an emergency.
When to get help
Call 999 or go to A&E if blisters on the skin comes with any of these warning signs:
- Call 999 or seek emergency care for widespread blistering with fever, or blisters affecting the eyes, mouth or genitals — this can be a severe drug or skin reaction.
- Seek urgent help for skin that is peeling away in sheets, or blistering with a high temperature and feeling very unwell.
- Seek urgent help for a hot, spreading, painful red area around blisters with fever, which can mean a spreading skin infection.
- Seek same-day advice for blisters following a burn that is large, deep, or on the face, hands or genitals.
- See a doctor promptly for blisters around the eye, especially with shingles affecting the side of the nose or forehead.
When to see a doctor
Most blisters heal on their own and need only simple care, but you should seek help if a blister becomes infected, is very large or painful, follows a significant burn, or keeps recurring without explanation. Honey-coloured crusting blisters, especially in a child, should be seen as impetigo is contagious and may need treatment. Seek urgent care for widespread blistering, blistering with fever, or blisters affecting the eyes, mouth or genitals, as these can signal a serious reaction. Blisters on the foot in someone with diabetes or poor circulation also warrant prompt review.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of blisters on the skin
Blisters on the skin has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
A small blister from friction or a minor burn is usually best left intact, as the overlying skin protects the raw area beneath and reduces the risk of infection. Cover it with a soft, clean dressing or plaster to cushion it, and avoid the rubbing or footwear that caused it. Try not to deliberately burst a blister; if it bursts on its own, keep the area clean and lightly covered and watch for signs of infection such as increasing redness, warmth, swelling or pus. For itchy blistering conditions, keep the skin moisturised, avoid scratching to limit infection and scarring, and keep your hands clean, since some blistering rashes such as impetigo and cold sores are contagious.
Answers
Blisters on the skin: frequently asked questions
Should I pop a blister?
Usually no. The skin over a blister protects the raw area underneath and lowers the risk of infection, so it is best left intact and covered. If it bursts on its own, keep it clean and lightly covered and watch for signs of infection.
How do I know if a blister is infected?
Signs include increasing redness, warmth, swelling, pus, an unpleasant smell, or worsening pain, sometimes with fever. If you notice these, see a doctor, as an infected blister may need treatment.
When are skin blisters an emergency?
Widespread blistering with fever, blisters affecting the eyes, mouth or genitals, or skin peeling away in sheets can mean a severe drug or skin reaction and need emergency care. Call 999 or go to A&E.
Are blistering rashes contagious?
Some are. Impetigo, cold sores, chickenpox and shingles are all caused by infections and can spread to others, so keep the area clean and covered, avoid sharing towels, and wash your hands carefully.
Sources
Where this is drawn from
- British Association of Dermatologists: blistering skin conditions.
- NICE CKS: Impetigo.
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