Blood Blister On Your Feet: The Do's and Don'ts

by Rebecca Rushton 6 Comments

It pays to have a healthy respect for blood blisters as they pose a heightened risk for infection. But do you know what makes a blood blister or black toenails? How do you deal with them? Do you pop them or not?

blood blisters on toes

Blood blisters under big toes (image credit)


Blood Blister Do’s

  1. Get the pressure off (or down)

  2. Stop the skin stretching and tearing by reducing friction!

  3. Be clean, use antiseptic and a sterile non-adherent dressings to protect from infection


    Blood Blister Don'ts

    1. Don't just ignore it and keep going or it will tear and be open to infection

    2. Don't ignore the benefits of lancing it (but only if the situation is right!)

    3. Don't neglect pressure relief and friction relief


      FAQs About Blood Blisters

      1. What causes a blood blister?

      The presence of blood in a blister indicates there is high pressure component. This high pressure causes deeper injury - injury to small blood vessels in the dermis. Blood then tracks into the epidermis and mixes with the normal blister fluid. That's why blood blisters often occur over joints and bony prominences: like the back of the heel, the toes and the metatarsal heads (ball of the foot).

      blister skin layers
      Blood vessels exist in the dermis, not the epidermis where blisters form. That’s why normal blisters are not filled with blood.


      2. What colour are blood blisters?

      In the initial stages, a blood blister looks red. Then as the blood dries and coagulates over time, is goes a purple or black. 

      If you notice a black spot on your foot, be mindful there are other diagnoses for this. Of highest importance would be melanoma, particularly nodular melanoma. If there has been no trauma to have caused a blood blister, please consult your doctor to rule out melanoma.


      3. How long does a blood blister take to disappear?

      Blood stains the skin cells it comes in contact with. It can take a month or more for that discolouration to disappear. We know it takes somewhere from 30 to 48 days for full epidermal cell turnover - that is for cells to travel from their deepest to most superfical, to be shed as dead skin cells. So it could take that long before all trace disappears. The blood will dry relatively quickly, assuming you take away the cause. If you don't deal with the cause, your blood blister will last longer. 

      There may be a lot of black dried blood that flakes away. Or there may be just a little.

      • It depends on how much blood there was initially.

      • It depends on how much of the blood resorbed.

      • And it depends on whether you reduce the excess pressure or not - it may be a perpetual blood blister if you don't do anything to stop it from forming.


        Blood Blister Causes

        1. Structural causes of blood blisters

        Bony prominences are at most risk, like a bunion for example. Having a bunion makes the forefoot wider. It's not necessarily the bunion itself at most risk of developing a blood blister. The weightbearing undersurface is - as the prominent joint bulges over the sole of the shoe. This provides a concentration of pressure. Coupled with high friction, there's a blood blister waiting to happen.

        blood blister edge of forefoot

        Edge Blood blister under a callous in the presence of a bunion (image credit: Sue’s Ramblings)

        toe blood blister
        Toe blood blister (image credit)


        2. Biomechanical causes of blood blisters

        The blood blisters under the big toes in the first image of this article are a consequence of the foot's biomechanics. There's an important function of the 1st MPJ (big toe knuckle) called the windlass mechanism. When it's not working adequately, there can be extremely high pressure under the joint of the big toe - where these blisters are.

        peak pressure under foot

        Functional hallux limitus (inefficient windlass mechanism) as a cause of blood blisters under the big toe.


        The best way to deal with this is with to see a Podiatrist because they know how to facilitate the windlass mechanism - treatment will likely include orthotics and calf stretches and maybe some other things, depending on where you're getting blood blisters.Treating Blood Blisters on the Feet

        If you miss the blister prevention boat and end up with a blood blister, follow the normal blister treatment sequence to get rid of that foot blisters. But now, preventing infection really is your priority! Consider the options below, depending on your blister location, the environment you're in and what gear you have access to. 


        1. Take away all pressure

        If it's possible, remove all pressure to ensure the blister roof remains intact and allow it to heal in its own time. For the blood blister on top of your toe, simply wearing open-toed sandals might work. Or open-backed scuffs for heel blisters. Barefeet or complete nonweightbearing may be your only option, depending where your blood blister is. By taking away all pressure, the blister remains intact with no chance of infection.

        But if your blood blister is on the weightbearing area of the foot, or you have to wear shoes, it's not quite so simple. 


        2. Reduce some pressure and cut friction levels

        There are parts of your foot where taking away all pressure might not be possible - like under the ball of the foot. And there are times when you just have to keep going. This is where pressure deflection can help in conjunction with reducing friction levels.


        donut pad
        This is a donut pad - it's very thin though. to provide more pressure deflection, use a thicker felt/moleskin material (Getty Images).


        • Reduce pressure with donut pads cut from thick adhesive orthopedic felt. You place the cavity over your blister to keep the pressure off it.

        • Reduce friction levels with Engo Patches. You stick these to your shoe or insole to stop the skin stretching and tearing the capillaries further.


        Adhsive orthopaedic felt - for making DIY donut pads Adhesive orthopaedic felt for making DIY donut pads - Learn more


        Popping Your Blood Blister

        There are times when keeping the blister roof intact is not the best option. It can be better to take matters into your own hands rather than ignore it and simply hope for the best. If you have the right equipment, you could deal with this appropriately and safely. It sure beats putting your blood blister with roof intact back into your shoe with no dressing and no pressure relief and just leaving it to chance. 

        However, please realise the risk of bacterial infection when you open up a blister. For the following few days, you'll need to be on the watch for signs of blister infection which include redness, swelling, pain and pus. And if you notice red streaks extending from your blister up your leg, this is serious and you need urgent medical attention. 

        Okay, so you've decided you want to lance your blood blister. Perhaps the amount of blood accumulating is causing pain; perhaps the blister is too big and likely to tear anyway; perhaps you have to carry on running or hiking and need this blister deflated. These are all legitimate reasons to po a blood blister... but only if you have the right gear! (One more time, remember, it is OK to not lance your blood blister. If in doubt, don't pop it! Read this article to help you decide if to lance or leave alone). 

        If you are going to lance your blister, here's what you'll need to do it so it doesn't hurt and to avoid infection (below). This is a great little kit. We sell the Sterile blister lance pack from our online store. With expedited shipping, you could have one of these in your hands tomorrow and start looking after your blood blisters, infection-free. There are enough items in this pack to provide 4 blister lancing and treatment episodes.


        Sterile blister lance pack


        Plus, I've included easy to follow instructions to help you every step of the way in lancing your blister safely and painlessly.  

        On a related note, if you’ve got a black toenail, here’s how to treat it by drilling the nail. You can use the hypodermic needles in the Sterile blister lance pack to perform this procedure.


        Blood Blister On Toe Or Finger

        Whether you've got a blood blister on your toe or your finger, the principles of treatment are the same. It's trickier on the feet though - not least of which is because we have to stand, walk and run on them. They are subject to high weightbearing pressures and high contact pressures from footwear. These forces can undo any healing we are trying to facilitate with our treatment.

        The other main difference between foot and finger blood blisters is our feet are generally a more germy environment, and so they're more susceptible to infection. Think about it... our feet keep us in contact with the ground, which is a germy environment. Then we cover them in socks and shoes and keep them out of sight. Think about the warm, humid and dark environment they live in.

        I trust the tips and techniques discussed in this article can help heal your blood blister. Please note that I am a podiatrist - I provide information about foot blisters (not blood blisters on legs, hands, the face or elsewhere).

        Rebecca Rushton
        Rebecca Rushton


        Podiatrist, blister prone ex-hockey player, foot blister thought-leaderauthor and educator. Can’t cook. Loves test cricket.

        6 Responses

        Bill Seigfried
        Bill Seigfried

        April 21, 2020

        On my big toe in my left foot right below my nail the skin is a reddish purple. It is tender and is seeping small amounts of blood. What should I. Do?

        Rob C
        Rob C

        March 29, 2020

        I had an unopened friction blister on my foot that filled up with dark dark (black) blood a few days later when I fell down the stairs. Over the last 2 weeks the blister has flattened but now the blood seems to be running away from the blister which is freaking me out a bit. Should I see a doctor?

        Grace Peniamina
        Grace Peniamina

        February 12, 2020

        hi, how do I know a blood blister is healing? The centre of it is still very dark but the outline of it is red

        Rebecca Rushton
        Rebecca Rushton

        January 09, 2020

        Hi Maulil. It will take 6 weeks for the last of the damaged skin to work its way to the surface before shedding as dead skin cells.


        January 06, 2020

        How much time it takes to heal the skin after draining the blood blister

        Joann Barbon
        Joann Barbon

        June 01, 2019

        Thank you for the information page,

        Leave a comment

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