Blisters

What are blisters?

A blister is a small bump on your skin filled with clear liquid. Think of it like a tiny water balloon under your skin. Your body makes blisters to protect damaged skin and help it heal.

Most blisters are filled with clear fluid, but some might contain blood (called blood blisters) and look red or black.

What causes blisters?

Blisters usually happen when something rubs against your skin repeatedly. Common causes include:

• Ill-fitting shoes rubbing your feet
• Using tools without gloves
• Burns from heat or the sun
• Skin reactions to things you're allergic to

Your body creates the blister as a cushion to protect the damaged skin underneath.

How to look after a blister at home

Do:

• Keep the area clean by gently washing and patting it dry
• Cover the blister with a soft plaster or padded dressing
• Wash your hands before touching a burst blister
• Let fluid drain out if the blister has already burst, then cover it

Don't:

• Pop the blister yourself
• Peel off the skin from a burst blister
• Pick at the edges of remaining skin
• Keep wearing shoes or using equipment that caused the blister

Getting help from your pharmacist

Your local pharmacist can recommend special plasters or dressings to protect your blister. They might suggest a hydrocolloid dressing - this is a special moist dressing that can help reduce pain and speed up healing.

When to get urgent help

Contact NHS 111 if you notice any of these warning signs:

• The blister is very painful or keeps coming back
• The skin looks infected - it feels hot and the blister contains green or yellow pus
• The skin around the blister looks red (this can be harder to spot on brown or black skin)
• You have a blister in an unusual place like your eyelids, mouth, or genital area
• Several blisters appear for no clear reason
• The blister was caused by a burn, scald, sunburn, or allergic reaction

Don't ignore an infected blister - without treatment, it could lead to a serious skin or blood infection.

When might you need to see your GP?

Your GP might need to safely drain a large or painful blister using a clean needle. If your blister is infected, they may prescribe antibiotics. They can also help if your blisters are caused by medical conditions like chickenpox, cold sores, or certain types of skin problems.

How to prevent blisters

• Wear comfortable, well-fitting shoes
• Break in new shoes gradually by wearing them for short periods
• Wear thick, moisture-wicking socks during exercise
• Change socks frequently if your feet get sweaty
• Use protective gloves when exercising or using tools at work

Remember, most blisters heal on their own within a week. While they can be uncomfortable, you don't usually need medical treatment unless you notice signs of infection or other concerning symptoms.

If you're worried about any blister, speak to your GP for advice.

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Based on NHS.uk guidance. Written by Dr Krishnan Pasupathi, NHS GP.