Blisters are bubbles under the skin filled with clear fluid. Sometimes they can be filled with pus or blood. They form when the skin has been damaged.
Blisters can be big or small.
The most common cause of blisters is friction – for example, new shoes rubbing against the back of the heel, or thumb-sucking.
Other causes of blisters include:
- burns, sunburn and scalds
- insect bites
- viral infections like chickenpox, cold sores and hand, foot and mouth disease
- bacterial infections like impetigo.
More rarely, some genetic disorders can cause blisters.
Does your child need to see doctor about blisters?
Probably not. But you should take your child to the GP if:
- the blister is smelly or filled with pus, or the surrounding skin is red, warm, swollen or tender, because this might mean that the blister is infected
- your child has a lot of blisters on their body, hands or feet
- your child has a fever
- your child is generally feeling unwell.
Treatment for friction blisters
Friction blisters usually heal without treatment.
If your child has a small blister, wash the area with a soap-free wash and water. Try to keep the area clean and dry.
Don’t burst or puncture the blister unless it’s causing a lot of pain. If the blister bursts on its own, cover it with a dressing to keep it clean and dry.
Watch the area for signs of infection.
Some blisters can be large and uncomfortable. They might take a long time to heal, because the fluid inside the blister slows down the healing process.
If your child has a big, uncomfortable blister that hasn’t broken by itself, you can take the following steps:
- Buy a sealed, sterile needle from a pharmacy.
- Prick the side of the blister with the sterile needle. Dispose of the needle safely straight after using it.
- Gently massage the fluid out of the blister. Smooth the top of the blister down over the base of the blister so it can act as a natural ‘bandaid’.
- Cover with a non-stick, dry dressing.
- Repeat as needed.
After this blister treatment, the blister should dry up in a few days and a crust will form. Let this crust peel off naturally. You can apply a petroleum jelly like Vaseline to the crust daily to soften it and help it heal.
If your child has a blister caused by shoes, it can help to have your child wear open shoes, or shoes that don’t press on the blister.
Blisters caused by things other than friction might need specific treatment, like antibiotics for impetigo or antivirals for severe cold sores.
Prevention of friction blisters
To prevent blisters from shoes, make sure your child wears shoes that are neither too tight nor too loose. If your child has new shoes, put sticking plaster on the back of their heels for the first week, until they wear in the shoes.
If your child’s thumb-sucking is causing blisters, you could try some of our tips for breaking habits.