Symptoms of blisters
Most blisters are filled with a clear fluid (serum), but may be filled with blood (blood blisters) or pus if they become inflamed or infected.
Blisters can be caused by:
- friction to the skin
- heat - for example, from sunburn or a scald
- contact with chemicals, such as detergent
- medical conditions, such as chickenpox and impetigo
Most blisters heal naturally after three to seven days and don't require medical attention.
As new skin grows underneath the blister, your body slowly reabsorbs the fluid in the blister and the skin on top will dry and peel off.
It's important to avoid bursting the blister, because this could lead to an infection or slow down the healing process.
You may choose to cover small blisters with a plaster. Larger blisters can be covered with a gauze pad or dressing that can be taped in place.
- Find out more about applying plasters and other dressings
When to seek medical help
You should see your doctor if you have blisters that:
- you think are infected – an infected blister will be filled with yellow or green pus and may be painful, red and hot
- are very painful
- keep coming back
- are in unusual places, such as on your eyelids or inside your mouth
- are caused by severe sunburn, burns or scalds or an allergic reaction
There are a number of ways to avoid getting blisters caused by friction, sunburn or chemicals. These include:
- wearing comfortable, well-fitting shoes
- helping keep your feet dry, for example, with thicker socks
- wearing gloves when handling chemicals
- using sunscreen
Blisters caused by a medical condition often can't be prevented and need to be treated by a doctor.