Blisters
What are blisters?
A blister is a small pocket of fluid which forms in the upper skin layers. They can form anywhere on the body, although blisters on the feet and hands are particularly common. Blisters are usually the result of injury, pressure or continuous friction to the skin and they form to help prevent further damage to deeper skin tissues. Blisters can range in size from the size of a pinprick, to several centimetres in diameter. Left unpopped, blisters usually take around a week to heal.2They may be painful, or may not cause any discomfort at all.
Depending upon how and where they form, blisters can contain serum, plasma, blood or pus. The most common types of blisters are:
friction blisters
blood blisters
heat blisters
Other types of blisters are named after the condition they are linked to and may include chicken pox and shingles blisters, herpes blisters and eczema blisters.
Symptoms of blisters
Symptoms of blisters may include:
a reddened, tender patch of skin
a raised lump filled with fluid which may be serum, plasma, blood or pus
pressure or pain around the pocket of fluid
itchiness around the blister
Causes of blisters
Blisters can be caused by several factors, with the cause often determining what kind of fluid is contained in the blister. Blisters can be caused by:
Friction — Repetitive friction or rubbing on the skin can cause blisters that fill with clear fluid. The most common type of friction blisters, are those that form on your feet after wearing poor-fitting or new shoes, or those that appear on your hands after using shovels, gym equipment or other tools. Clothes that rub on the skin can also cause blisters.
Pinching or crushing — If skin is pinched or crushed it can result in the rupture of small blood vessels near the skin. Blood from these vessels can leak between the layers of skin causing a blood blister (blister filled with blood).
Extreme temperatures — Burns or scalds to the skin, including sunburn can cause heat blisters, while frostbite can also lead to blisters.
Chemical exposure — Chemicals found in cosmetics, detergents, solvents, nickel, and even in insect bites and stings can cause allergic reactions, leading to blisters.
Medical conditions — a number of medical conditions can also cause blisters. These include:
chicken pox and shingles
cold sores
genital herpes
school sores
cellulitis
hand foot and mouth disease
eczema (atopic dermatitis), including dyshidrotic eczema
autoimmune diseases such as bullous pemphigoid, pemphigus, dermatitis, herpetiformis
fungal skin infections, such as tinea
radiation exposure
How to treat blisters
Most of the time blisters won’t require medical attention, unless they are related to a medical condition, illness, severe burn, or become infected. As new skin grows beneath the blister, the fluid will slowly disappear and the skin should naturally dry, peel off and heal This will usually take around a week.
The fluid inside the blister is sterile so it’s best to avoid popping it. If your blister bursts, you should allow the fluid to drain naturally and then cover it with a special film-like bandage that is breathable, waterproof and allows the area to stay clean. This dressing can stay on the area for a number of days as the natural fluid from the body will help heal the area. These may also alleviate pain by cushioning the blister and preventing painful rubbing.
Avoid the temptation to peel off the top of the blister, as this provides protection from infection. You should also take care not to apply sticky dressings or tape directly to the blister as removing them may rip off the top of the blister. Your pharmacist will be able to provide advice on the right products to alleviate symptoms and aid healing, including over-the-counter (OTC) pain medication if appropriate.
Should you pop blisters?
It’s best to avoid popping blisters if you can help it, as the blister bubble provides a protective layer that prevents bacteria from entering and causing an infection. If the blister is so large or painful that it inhibits you moving around, and you need to drain the fluid, you should:
wash your hands and the blister thoroughly
sterilise a clean needle with rubbing alcohol
carefully pierce the edge of the blister to allow the fluid to drain away
wash the blister again
apply antiseptic or antibacterial cream or ointment
cover with a bandage or sterile dressing
Complications of blisters
The main complication with blisters is the risk of infection, particularly if they have burst or you have popped them. Left untreated, infections can spread to other areas of your body. If it spreads to your bloodstream or lymph nodes, it can become a medical emergency.
When should you see a doctor?
You should see your doctor if you think your blisters are related to a medical condition, as you may need treatment. You should also see your doctor if a blister shows signs that it is infected. Key things to look for include:
a hot, painful or throbbing sensation around the blister
red streaks around the blister
yellow or green discharge (pus) coming from the blister
It’s also important to visit your doctor if you have blisters with accompanying fever, chills or other flu-like symptoms, or if you have blisters around your eyes or genitals.
How to prevent blisters?
No one likes blisters. Fortunately, there are a number of things you can do to prevent them from forming. These include:
wearing shoes that fit properly and don’t rub
wearing moisture-wicking socks, especially when exercising
changing damp socks promptly
taping a ‘hot’ area on your foot before it turns into a blister
wearing protective work gloves when using tools
guarding against sunburn by using sunscreen and wearing protective clothing
avoiding unnecessary contact with chemicals or other substances that may trigger conditions such as dermatitis
taking care when dealing with hot objects, including steam
Blisters can be painful and uncomfortable, but we are here to help. Speak to your local MediADVICE pharmacist about your symptoms so we can recommend pain relief products, medications and first-aid products that may help you manage the symptoms of your blisters.