Most of us have at some point experienced a blister or two. We know how painful and uncomfortable they are but thankfully, they ease within a short space of time. A blister is a small, fluid filled balloon of skin which forms on the surface of the skin due to friction, i.e. rubbing of the skin against a hard surface.

This results in damage between the top layer of skin and the layers underneath. The skin is pushed outwards and experiences a rush of fluid (serum) to the affected area, causing it to balloon outwards into a blister. This protects the damaged area and enables it to heal.

Blisters affect anyone, young or old, male or female but they are very easy to treat.

Is there more than one type of blister?

There are several types which are as follows:

  • Normal, clear blister
  • Blood blisters
  • Infected blisters

Clear blister

The normal, clear blister is the most common variety. This is filled with a fluid called serum which is a vital component of blood along with clotting agents and blood cells.

Blood blister

Blood blisters form when a small blood vessel near the top of the skin is damaged which leaks blood into the tissues. This results in a blood filled sac on the skin. This type of blister occurs if the skin is pinched or squeezed very tightly.

Infected blister

Infected blisters are blisters filled with pus as a result of an infection or injury. They are sore and painful to touch.

Causes of blisters

The most likely cause is damage to the skin caused by rubbing, pinching or some other form of friction. A classic injury is where a blister on the heel forms due to badly fitting shoes. This causes them to rub against the heel, irritating the skin and leading to the formation of a blister.

Does this sound familiar? If you undertake exercise such as running then you will be very familiar with this type of injury. This often occurs when breaking in new running shoes or wearing a pair which do not suit your feet and running action.

Blisters also develop on the hands, often as a result of friction between a tool, e.g. garden spade and the palm of the hand. This is particularly the case in warm weather as the hands perspire which causes them to move around and increase the friction.

Other causes include:

  • Extreme heat, e.g. sunburn or a scald
  • Allergic reaction to a substance or a household product
  • Medical condition, e.g. cold sores

Conditions such as impetigo and chicken pox can also cause blisters.

Symptoms of blisters

Your blister (or blisters) will take on one of three appearances:

  • Clear
  • Blood filled
  • Infected, e.g. pus

Their appearance often depends upon the cause of the blister, for example excessive friction will lead to a blood blister. If you have an infected blister then seek medical attention as this can lead to complications.

You may have a single blister or a crop of blisters. Some blisters are painless and can be touched whereas others are tender even with the slightest touch.

The healing process involves the formation of new skin under the blister which takes a few days. Fluid inside the blister is reabsorbed and the blister itself dries out and falls off.

Should you burst a blister?

There are arguments for and against this but experts recommend that you avoid doing so as it slows down the healing process. Plus it can lead to an infection.

Your GP or practice nurse will burst a large blister or a clump of them but under safe conditions.

But if you have a blister which has already burst then cover the area with a clean dressing and allow it to heal. Do not peel away the top of the blister or the surrounding skin.

Diagnosing blisters

Blisters are a common condition which you can treat without need of medical attention. The only exception to this are infected blisters and blisters which occur for no obvious reason. In the latter case this may be due to an underlying medical condition which needs investigating.

Treatment for blisters

If you are treating a blister at home then place a dressing or a special blister plaster over the affected area. But a small blister can be left to heal by itself.

If you have a blister which has burst without any intervention by you then leave it to dry and then cover the area with a dressing. This will prevent the risk of an infection and allow it time to heal.