How to Tell if Your Blister Is Infected


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.

Behind your blister

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.

Identifying an infected blister

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.

Treating infected blisters

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.

If the infected blister doesn't respond quickly, we recommend that you come to see us so that we can evaluate the infection and place you on oral antibiotics.

If you have diabetes, any open wound in your feet is cause for concern, so we advise that you come to see us if your blister looks potentially worrisome. In other words, don’t wait to see if topical antibiotics will work as we want to take more aggressive steps right away to fight off the infection.

For treatment of your infected blister, please contact one of our offices in Hermitage, Brentwood, Nashville, Mount Juliet, Waverly, Smyrna, Gallatin, Columbia, Pulaski, or Lebanon, Tennessee, to schedule an appointment.

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