Infected Blister? How To Tell & What To Do About It

infected blister on toe lance pus

If getting a blister isn’t bad enough, the last thing you need is for it to get infected. An infected blister gets worse before it gets better. It becomes red and painful, takes longer to heal, and as you'll see at the end of this article, can lead to some very nasty consequences.

What Does A "Healthy" Blister Look Like?

A normal healthy blister contains thin watery blister fluid that is colourless or a very light yellow colour. Blister fluid will be pink or red in the case of a blood blister. However, pink/red doesn't mean your blister is infected. All it means is damage has occurred to a small blood vessel and blood has leaked into the blister. Rest assured, these blister presentations are considered normal and uninfected.

Normal healthy uninfected blister

Normal (non-infected) blister fluid is thin and clear, like this.

What Does An Infected Blister Look Like?

There are some tell-tale signs that your blister is infected.

  • Pus: Instead of thin colourless blister fluid, an infected blister contains a thicker cloudy yellow or green fluid called pus.
  • Redness: The immediate area of skin around the blister is often red, and in fact, this redness worsens over time.
  • Swelling: The immediate area of skin around the blister may be a bit puffy. Again, this swelling worsens over time when there is infection.
  • Pain: There will likely be increased tenderness that gets worse rather than better over time.

See how the blister fluid here is yellow - this is actually pus. Pus occurs when there is bacterial infection.

How To Treat An Infected Blister

Most infected blisters can be successfully treated at home without the need for medical consultation. It’s very easy to do yourself. All you need is the right products and diligence in monitoring your blister for changes. Here’s what you need to know…

Products You’ll Need:

✔️ Clean Hands

Wash with soap and water or rubbing alcohol

✔️ Sterile Lancing Implement

I like using a scalpel blade or hypodermic needle. Don’t use a heated pin or sewing needle over a flame for these reasons.

✔️ Cotton Buds

To gently ease any blister fluid out, to wipe debris from your blister and to apply your antiseptic / antibiotic.

✔️ Cottonwool or Gauze

To wipe debris from your blister, soak up any blister fluids and dry your blister before applying your dressing.

✔️ Antiseptic or Antibiotic

Either antiseptic solution such as povidone iodine, or antibiotic ointment such as Neosporin. Along with your body’s immune system, these products will kill the germs in your blister.

✔️ Island Dressings

To protect the blistered skin and keep new germs out.

Get It All In Our Sterile Blister Lance Pack

You can pick up our Sterile Blister Lance Pack here. It contains everything you'll need for 4 blister lancing/treatment episodes.

Treatment Procedure For Intact, Torn or Deroofed Blisters

If Your Infected Blister Is Deroofed:

Simply wipe any debris away, apply your antiseptic/antibiotic and cover it with an island dressing. Don’t forget, we’ll be monitoring it closely over the next few days.

If Your Infected Blister Is Torn:

Be sure to remove as much debris as you can from under your remaining blister roof. This debris is harbouring the very bacteria you are trying to kill. Physically removing it is a high priority. Make sure your antiseptic/antibiotic gets into all the nooks and crannies under your blister roof. I like to use a liquid for this reason.

If Your Infected Blister Is Intact And Full Of Pus:

It is advisable to lance and drain the infected blister, and then follow the above steps. I have several blister lancing videos here showing you how to perform the procedure easily, safely and painlessly.

The Importance Of Monitoring Your Infection

Your infection won’t clear up immediately after one episode of the above procedures. In fact, the infection may not clear at all. That’s why we have to monitor our infected blisters closely and repeat the above procedures.How often? Twice a day should be enough. Change your dressing more often in the following situations:

Your Dressing Gets Wet:

The last thing you need is a soggy dressing sitting on your infected blister all day. Take the wet one off, apply some more antiseptic/antibiotic and put a nice clean one on.

You Notice Strikethrough:

Strikethrough is evident when your blister exudates (fluid, pus, blood etc) have soaked right through the island of your dressing. As soon as strikethough happens, bacteria can travel through your dressing. Take the dirty one off, apply some more antiseptic/antibiotic and put a nice clean one on.

When Medical Urgency Is Required

Infected blisters can morph into a more urgent situation that requires medical attention. At this point, you’ve not managed to get on top of this infection. The infection is spreading from the immediate area to involve other bodily systems and functions. You need to see a doctor *today* with your infected blister if:

  • After 3 days your blisters continue to become more red, swollen, painful and weepy.
  • You see reddish streaks radiating from your blister.
  • You have a fever or chills

Possible Complications

An unchecked blister infection can lead to serious health conditions. People have actually died or lost limbs due to infected blisters. President Coolidge's son Calvin Jr. died at 16 years of age in 1924 due to an infected blister on the top of his 3rd toe right foot from playing tennis with his brother. At this time, penicillin was yet to be discovered. But antibiotics are around today so there's no excuse for sitting on your hands while your infected blister gets worse and worse. In the modern day, many famous people, from models to sports stars, have felt the effects of blisters that get infected. Here's an example from Kate Miller-Heidke on Twitter after Eurovision:For anyone interested, I was diagnosed with cellulitis resulting from an infected blister. It’s the exact same disease Hilary Swank got while training for Million-Dollar baby so it’s definitely the most glamorous foot infection going around.And blisters are often the starting point of an amputation in people with diabetes and peripheral neuropathy.Here's what you need to know...


Cellulitis is a serious and painful skin infection that occurs when bacteria penetrate into deeper layers of the skin. It often requires hospitalisation and oral or intravenous antibiotics. At this stage, you'll be starting to feel unwell. And it's only going to get worse during the following escalations.

An infected blister can lead to cellulitis

Cellulitis (Flickr mikeblamires/125281197) - The black line has been dawn. With cellulitis, the demarkation between affected and unaffected skin is often quite definite.


Red streaks around your blister indicate lymphangitis. This isn’t blood-borne infection, but the infection is starting to spread into the superficial lymphatic vessels. This is a warning that you need to see a doctor about this infection today. If you don’t, the following more serious health conditions may result.Infected blister can lead to lymphangitisLymphangitis - red streaks eminating from the source of the infection (James Heilman, MD)


This is the medical term for blood-borne infection. The bacteria have entered the bloodstream and now passing through your organs. Clearly, this is not good. At this stage, you're really crook, and you're feeling it!


By now, you are drastically unwell! In fact you might not know much about anything at this stage due to your altered mental state, along with the fever, low body temperature, rapid heartbeat and breathing difficulties. These symptoms are all part of the infection's assault on your organs. Urgent specialist medical care is required. Call an ambulance!

Moral Of The Story

Look after your blisters, people!

Give Your Blister Excellent First Aid

Prevent infection with the Sterile Blister Lance Pack

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