A bulla (plural: bullae) is a medical term that describes a fluid-filled blister that forms on the skin. These blisters can occur for a variety of reasons, including burns, infections, or other skin conditions. A burn blister is a specific type of bulla that forms on the skin as a result of a burn. Burn blisters occur when the top layer of skin (epidermis) is separated from the underlying layer (dermis) by the action of heat, resulting in the accumulation of fluid between these layers.

Causes and mechanism

Burn blisters are usually caused by:

  • Thermal burns : Caused by direct contact with fire, hot liquids, steam or other heat sources.
  • Chemical burns : Caused by harsh chemicals such as acids or alkalis that damage the skin.
  • Sunburn : Excessive exposure to UV radiation can also cause burn blisters.

The fluid in burn blisters, often called serum, helps protect and heal the damaged tissue. Although they can be painful, burn blisters play an important role in the healing process by providing a barrier against infection.


Treatment for burn blisters depends on their size and severity:

  • Small burn blisters should ideally be left intact to minimize the risk of infection. Covering it with a sterile bandage can help protect the blister.
  • Larger or ruptured blisters require more careful attention to prevent infection. Clean, open blisters should be cleaned with an antiseptic solution and covered with a sterile bandage.
  • Pain relief can be achieved with cooling compresses or taking painkillers such as paracetamol or ibuprofen.

When to seek medical attention

It is important to see a doctor if:

  • The burn is large or is on sensitive parts of the body such as the face, hands, feet, genitals or large joints.
  • Signs of infection occur, such as increasing redness, swelling, pain or pus.
  • The blister was caused by an electrical burn or a severe chemical burn.
  • The affected person belongs to a risk group, such as children, the elderly, or people with a weakened immune system.


To avoid blisters, basic safety measures should be taken, such as wearing protective gear when handling hot objects or chemicals and applying sunscreen to prevent sunburn. It is also important to be aware of the risks in the kitchen, bathroom, and other activities where burns can occur.

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