can blisters get infected?

An infected blister will be filled with yellow or green pus and may be painful, red and hot. It's important not to ignore an infected blister because it could lead to secondary impetigo (a contagious bacterial infection of the skin) and further complications, such as cellulitis or sepsis.

You might get a friction blister from wearing a new pair of shoes or wearing shoes that are too tight, for example. Other causes of blisters include burns, certain types of eczema (an inflammatory skin condition), and the herpes simplex virus.

Most blisters will heal when left alone and are very unlikely to become infected. If you decide to pop a blister, though, you increase your risk of infection. A few key signs can signal that a blister is infected.

This article will discuss the signs of an infected blister, complications of infection, how to treat a blister, and when to call a doctor.

Your blister may be infected if it’s:

A blister can become infected if it bursts prematurely (or you pop it open), and bacteria are introduced into the wound. Depending on the bacteria causing the infection, symptoms may vary in severity.

Cellulitis is an infection of the deeper layers of the skin. The condition is caused by various types of bacteria—most commonly, group A Streptococcus.

Signs of this type of infection include:

You have an increased risk of contracting cellulitis if you have chronic edema (tissue swelling).

To treat this infection, doctors will prescribe oral antibiotics. If the infection has been left untreated, intravenous (IV) antibiotics may be necessary. If left untreated, cellulitis can lead to complications such as endocarditis (infection of the inner surface of the heart) or bacteremia (infection in the bloodstream).

Sepsis, or bacteremia, is an infection that occurs when bacteria end up in the bloodstream. This can happen when an infected skin wound is left untreated. When it reaches the bloodstream, the infection begins to affect your entire body.

Antibiotic treatment is necessary to prevent complications of sepsis such as septic shock (a severe reaction to infection), which is a potentially fatal condition.

Properly caring for a blister can help prevent infection. But you should monitor it for signs that you need to contact a healthcare professional.

If you note any signs of infection, lightly apply an antibiotic ointment to the inflamed area and cover it with a clean bandage. Call your healthcare professional for advice. Do not ignore these signs.

If you notice any signs of infection, call your healthcare professional to arrange for treatment. An infected blister may require prescription antibiotics and professional wound care.

You should also see a doctor if your blister (or blisters):

Most friction blisters will go away on their own. However, sometimes, they can burst open on their own before the wound is fully healed. This can lead to infection. In addition, not taking proper hygiene measures when popping a blister can also cause it to become infected.

Signs of infection include pain, swelling, redness, red streaks, heat, and pus drainage. You may also have a fever if your wound is infected. If you notice your blister is getting worse and seems infected, you should make an appointment with your healthcare professional.

Most skin wounds go away on their own. But in some cases, they can become infected. To prevent an infection from happening in the first place, avoid popping blisters and keep the area clean. And if you have to touch your blisters, always make sure to wash your hands before doing so.

Are you worried that your blister is infected but not sure whether it actually is? Call your doctor’s office or contact a telehealth service for advice.

You’ve been anxious to debut a new pair of shoes, and you spent the day showing them off — only to find that, at the end of the day, you’ve developed a blister or two. Or perhaps you went on a long hike or run, and blisters developed as a result of the increased demand on your feet.

Whatever the case, blisters on your feet are quite common and, in most cases, aren’t cause for concern (aside from the discomfort for a few days). That said, there are times when blisters can become problematic, such as when they become infected.

To help you identify an infected blister on your foot, the team of podiatrists here at Neuhaus Foot and Ankle pulled together the following information on blisters and the potential warning signs of an infection.

A blister is your skin’s response to too much friction. When your skin encounters friction, the skin begins to weaken and break apart, forcing your tissue to find ways to fill in the gaps and protect itself. To do this, it forms a fluid-filled sac just underneath your epidermis — the outermost layer of your skin. This sac may contain a clear liquid or blood if a blood vessel is impacted by the friction.

Since blisters occur due to friction and pressure, it makes sense that they commonly form on your feet, especially if you’re wearing new shoes that haven’t formed to your feet, or you’re using your feet more than usual. As well, if you have bunions or hammertoes, you may be more prone to blisters.

While friction is the most common cause of blisters, these protective sacs can also form in response to an insect bite, burns, frostbite, contact with chemicals, and other outside forces.

In most cases, blisters resolve on their own, but it’s important to protect the area while your skin heals. If you don’t protect your blister, it can rupture too early, leaving the area open and vulnerable to infection.

The most common signs of an infected blister are:

Another sign of an infected blister is one that doesn't heal on its own and, when you apply pressure, it oozes liquid or pus and is very tender to the touch.

Another problem we see is blisters that form under calluses, which prevent them from releasing the liquid.

Your first steps should be to clean the area with soap and water, thoroughly dry it, and then apply a topical antibiotic cream to the infected blister.

Noticing and treating the infection early will usually prevent complications. Without treatment, the infection can potentially involve more areas of the skin or enter the bloodstream.

This spreading can lead to serious health conditions, such as:

Cellulitis is a common skin infection that can be serious.

It happens when germs get into the deep layers of skin and affect the tissue underneath. People may also develop a fever and blisters on the surface of the infected area.

Red or swollen skin that feels warm or tender is the first sign of cellulitis. If a person does not get treatment, the infection can spread into the bloodstream.

Anyone who is concerned that they have cellulitis should speak to a doctor as soon as possible.

Bacteremia refers to bacteria in the blood. It happens when an infection in one part of the body spreads into the bloodstream.

Sepsis happens when the body reacts too strongly to the germs as they spread through the blood.

The body uses inflammation as part of its natural defense system. As it works to fight the germs in the blood, the inflammation and resulting changes in the blood flow cause life-threatening organ dysfunction.

Sometimes, sepsis can lead to septic shock. In this situation, the person requires certain medications to keep their blood pressure at a safe level.

Signs and symptoms that an infection has spread to the blood may include:

• Clean the wound. Run the area under warm water and gently massage it with soap.
• Soak the wound. Soak your wound in a homemade saline solution.
• Treat the wound. After washing both your hands and the wound, apply a topical antibiotic ointment, such as Neosporin or Bacitracin.
• Treat the pain.

Fluid collects under the damaged skin, cushioning the tissue underneath. This protects the tissue from further damage and allows it to heal.

Most blisters are filled with a clear fluid (serum), but may be filled with blood (blood blisters) or pus if they become inflamed or infected.

Most blisters heal naturally after three to seven days and don't require medical attention.

It's important to avoid bursting the blister, because this could lead to an infection or slow down the healing process.

If the blister does burst, don't peel off the dead skin. Instead, allow the fluid inside the blister to drain and cover the area with a dry, sterile dressing to protect it from infection until it heals.

Read more about treating blisters.

See your GP if you have blisters that:

An infected blister will be filled with yellow or green pus and may be painful, red and hot.

It's important not to ignore an infected blister because it could lead to secondary impetigo (a contagious bacterial infection of the skin) and further complications, such as cellulitis or sepsis.

You should also talk to your GP if you have blisters in unusual places, such as on your eyelids or inside your mouth, or if they appear after severe sunburn, burns or scalds or an allergic reaction, or after coming into contact with chemicals or other substances.

Blisters can be caused by:

Read more about what causes blisters.