What is a blister?

A blister is a bump on the skin containing fluid. Blisters are usually circular in shape. The fluid that forms underneath the skin can be bloody or clear.

What causes a blister?

Causes of blisters include the following:

  • Burns/scalds
  • Sunburns
  • Friction (from a shoe, for example)
  • Contact dermatitis
  • Bullous Impetigo (a contagious infection of the skin)
  • Viral infections (including chickenpox, herpes zoster, and hand-foot-mouth disease )
  • Rare genetic conditions (including epidermolysis bullosa)

The symptoms of a blister may resemble other skin conditions or medical problems. Always consult your child's physician for a diagnosis.

First-aid for blisters

Blisters often heal spontaneously. Treatment will vary according to the cause. Some general guidelines for treatment may include:

  • Wash the area with soap and water.
  • A cold or ice pack may help reduce swelling and discomfort.
  • Keep the area covered with a bland ointment such as Vaseline.   Avoid antibiotic ointments unless directed by your physician.
  • If the blister bursts, place an adhesive bandage or dressing on the area to keep it clean.  Do not peel away the overlying skin. 
  • If the blister is very tense and painful, you may ask guidance from your physician on how to drain the blister for relief.
  • Observe the area for signs of infection such as increased warmth, swelling, redness, drainage, pus formation, or pain. If you notice any signs of infection, call your child's physician. Antibiotics may be needed.