Causes of blisters

Children get blisters when fluid builds up under their skin. This happens because of damage to the skin. The most common cause of a 'water blister' is friction - for example, new shoes rubbing against the back of your child's heel.

Other common causes of blisters include burns (including sunburn). Your child could also get blisters with insect bites and eczema.

Blisters are often caused by viral infections like chickenpox, cold sores and hand, foot and mouth disease. Bacterial infections like impetigo can cause blisters too.

When to see your doctor about blisters

You should take your child to the GP if:

  • the blister is smelly or filled with yellow-greenish fluid (pus), or the surrounding skin is red, warm, swollen or tender, because this might mean that the blister is infected
  • your child has lots of blisters and a fever
  • your child isn't well.

Blister treatment

Small blisters usually heal by themselves, so you can just put a bandaid on them.

But some blisters can be very 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:

  1. Prick the side of the blister with a sterile needle. To sterilise the needle, pour boiling hot water over it, or wipe it with an alcohol wipe.
  2. Gently massage the fluid out. Smooth the thin covering of skin down over the base of the blister so it can act as a natural 'bandaid'.
  3. Cover with a non-stick, dry dressing.
  4. 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.

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 other things might need specific treatment, like antibiotics for impetigo or antivirals for severe cold sores.

Prevention of blisters

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 her heels for the first week, until she 'breaks in' the shoes.