How to Heal a Blister
Medically reviewed by William Truswell, MD
Most people have had blisters—painful or itchy bubble-like pockets of skin filled with fluid. A common type of blister is caused by friction, and though they can appear almost anywhere on the body, feet are particularly vulnerable to them.
Friction blisters develop when something rubs your skin enough to weaken the top layer, such as tight shoes. The outer skin separates from the layer beneath, and your body responds to the injury by creating a protective cushion of fluid.
This article will explore what blisters are, what's inside them, and how to help them heal.
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Causes of Blisters
When something irritates or injures the skin, it can cause a blister, also known as a vesicle. A common type of blister is a friction blister.
Friction blisters occur when something rubs the skin, such as tight shoes or a hand-held tool. They can develop if the pressure is repeated over time or if there is a short, intense pressure.
Friction blisters on the feet are very common, especially in people who walk or hike long distances, such as hikers or soldiers. Factors that cause friction blisters in feet include:
Moist skin
Warm temperatures
Carrying a load, such as a backpack
Long-term activities
Footwear that fits improperly
Wearing shoes before having gradually conditioned the feet in them
Other Types and Causes of Blisters
Other than friction blisters, you may experience blisters due to the following causes:
Heat, cold, or radiation injury to the skin, including burns, sunburns, scalds, or frostbite (after rewarming)
Pinched skin, such as catching a finger in a drawer
Reactions to allergens such as poison ivy or poison oak or chemical products like detergent
Infections such as herpes, chickenpox, shingles, impetigo, or cellulitis
Skin conditions such as eczema (atopic dermatitis)
Stevens-Johnson syndrome, a reaction to medication or infection that can be life-threatening
Some relatively rare autoimmune disorders, including dermatitis herpetiformis, which affects adults with celiac disease, or bullous pemphigoid, which causes large blisters, often on the thighs or armpits.
Why Do Blisters on Feet Hurt?
Blisters on your feet hurt because the epidermis (the top layer of the skin), which is less sensitive than underlying layers, has been damaged. The layer of skin underneath (the dermis) has more nerve endings, so when anything touches it, the blister fluid presses on the nerve endings.
Symptoms of Unopened (Bubble) Blister
A blister looks like a bubble on your skin. You may have one or many of them. The fluid inside can be clear liquid or blood. Blood blisters may look reddish, black, or purple. Blisters are usually very tender to the touch, and pain is a primary symptom of a bubble blister.
Symptoms of Open Blister
An open blister is one that has popped, further exposing the damaged area of skin. It may be very painful.
Infections can occur in open blisters. If you see pus, your skin feels warmer around the blister, or you see red lines in the skin around the blister, you could have an infection. If you think you have an infected blister, see a healthcare provider.
Function of Blister Fluid
The clear liquid inside a friction blister is called serum. It is made of water, protein, and carbohydrates that leak from injured blood vessels. The serum has an important function because it cushions and protects the underlying tissue, allowing it to heal more quickly. The fluid will be reabsorbed as the skin heals.
Blisters that are filled with blood form if your skin gets a severe pinch. The blood comes from vessels that were damaged in the injury and can have the same protective function as serum.
Sometimes, blisters can be filled with pus if they are infected.
Other Places on the Body That May Develop Blisters
Friction blisters generally occur on areas with a thicker layer of the outer skin (stratum corneum), usually the palms, soles, or other areas of toughened skin.
However, you can develop blisters from other causes almost anywhere on your body that is covered in skin. Certain health conditions can lead to blisters on particular parts of the body or over your whole body.
Blister Treatment: What to Put on Skin
Blisters usually heal on their own, but you do want to avoid infection and minimize pressure on the blister to avoid pain.
Healthcare providers recommend you do not pierce, pop, or "unroof" a blister, especially blisters about one-half inch (5 millimeters) or less in size. Doing so increases the risk of infection. Blisters typically heal within a week to 10 days.
Here's how to treat a blister:
Wash the area gently with a mild soap and keep it clean and dry.
Try to keep the top layer of skin attached to the blister if it bursts on its own.
Put padding around the area, which will help avoid pressure.
Tape the blister if it has not burst and the area is clean and dry.
If it bursts, watch for signs of infection, and call a healthcare provider, if necessary.
For larger blisters, some people choose to drain the blister. This is best done by a healthcare provider. Wait a full day after the blister develops before considering draining it.
If choosing to self-treat, use a needle sterilized with rubbing alcohol to pierce one edge of the blister. Wash the area gently. Apply a thin layer of petroleum jelly (antibacterial ointment may also be considered for a drained or burst blister). Cover the drained blister with a bandage to protect it from further damage.
How to Avoid Blisters From Walking
Precautions you can take to avoid blisters on your feet from walking include:
Wear shoes that fit comfortably (being neither too tight nor too loose while walking) and don't rub against your skin. Note that your feet will swell on longer walks, and plan for needing extra space in the shoe.
Progressively increase the time and distance you walk in a pair of shoes to toughen your feet gradually.
Wear moisture-wicking socks (socks that draw sweat away from your feet) rather than cotton socks. Wear socks appropriate to activities like exercising or sports that stay in place on the foot and don't bunch up.
Lubricate areas prone to friction, like between the toes, the heel, and the sole, with petroleum jelly or other lubricant products. Or, use powder (such as cornstarch) that helps keep these areas dry.
Before the activity, wrap your feet or toes with tape designed for walking or exercising for a long time or distance.
Change your socks if your feet sweat or get wet. Damp skin is more easily damaged by friction.
If you feel a spot becoming sore, try to stop what you're doing and eliminate the source of the friction.
Use antiperspirant on your feet to reduce sweating (but be aware of possible irritation from this method).
Risks of Untreated Open Blisters
Infection is the primary risk for open blisters. If you see signs of infection, contact a healthcare provider for treatment. These signs and symptoms include:
Redness around the area of the blister
A feeling of warmth in the blister
Pus in the blister
Red streaks on the skin leading from the blister
When to See a Healthcare Provider
In some cases, blisters can indicate conditions that need medical treatment. These include:
Blood blisters near the mouth, which can be a sign of several conditions, including angina bullosa haemorrhagica, a rare and benign (noncancerous) condition
Blisters that cover large areas or your whole body
Blisters that show signs of infection or are not healing
If you have diabetes or circulation problems, see a healthcare provider for any friction blister or other skin injury.
Summary
Blisters are bubbles or pockets of fluid on your skin caused by irritation and injury. Blisters are painful, but they will generally heal on their own. Keep the area clean and dry. Cover the area around the blister with a clean bandage to relieve pressure.
Help prevent blisters by wearing well-fitting shoes and socks and stopping activity if you feel a sore spot on your feet. If you note signs of infection, see a healthcare provider.
Read the original article on Verywell Health.
