Smart Sock 3: Avoiding Red Marks

What Causes Red Marks and How Do I Avoid Them?

Your baby’s well-being is our top priority and we know it’s yours too. We are committed to the quality of our product, and as parents ourselves that use the product with our own children, we stand by it. A small number of our users notice red marks on their baby’s foot after use of the Owlet Smart Sock. While this is not a common occurrence, we take this seriously, which is why we want to address these red marks head on. Just like a baby shoe that is too tight or too small, it can be uncomfortable for your child and leave marks. Our research, in partnership with dermatologists and pediatricians, shows that these marks are not electrical or thermal burns. These red marks can occur in the following areas:

Baby skin is soft, sensitive and can be quite hydrated. In the spot where the sensor sits, the skin doesn’t get the chance to breathe as well. If the sock is on one foot throughout the night, it is possible to develop an indentation in that area. Fortunately, this is very superficial and typically resolves within 30 minutes.


With newborns, it is possible for them to develop a “water bubble” in that area. Fortunately, these are also very superficial and reabsorb throughout the day. If this is something your little one experiences, we recommend switching to the other foot once during the night until about 1 month of age to give the skin a chance to dry out more.


You may also notice redness around the circumference of the ankle, similar to when we wear socks and can get a red line. This usually fades quickly as well. In some instances of dry skin, it may linger throughout the day. Using something like lotion, Vaseline, or Aquaphor when the sock is not on, will keep this area hydrated. 


Red areas can occur along the side of the foot occasionally as well. This is usually due to pressure from either having the sock on too tight, or if your little one tends to be a side sleeper and their body weight is now resting on the sensor. This too generally fades quickly, but can be avoided by ensuring a proper fit and switching the sock to the other foot if your baby typically sleeps on the one side. 


Other Suggestions:


Unwashed Smart Sock 3 Sensor

Sometimes we see red marks appear on a baby's foot when the Smart Sock 3 sensor has not been washed frequently enough, and especially when it has not been washed at all. It is important to know that not only should you wash the fabric Sock regularly, but you should also wash the sensor. It may feel odd putting an electronic device under running water, but the sensor was engineered specifically to be washed regularly. Without proper washing, dirt and oils collect in the fabric. As a result, the soft fabric can no longer do its job of wicking away extra moisture. Redness and irritation can occur when a moist or unclean fabric is on a baby’s sensitive skin for an extended period of time. 

We recommend washing the Smart Sock sensor and fabric sock every other week, and more often if it begins to look or smell soiled. Wash by hand with gentle detergent under cold running water. Gently scrub the fabric with your fingers, releasing any buildup of dirt, oils, or bacteria. Pat dry with a towel, and then let air dry. Please make sure the sensor is fully dry prior to use.  


Check the Size

Try going up a sock size or loosening the straps on the fabric socks. They should lay flat without any ripples or puckers. Ensure the Velcro is lined and adhering fully to the sock.

As babies grow, their feet get rounder. This can interfere with the pulse oximeter’s ability to get a good reading – causing yellow notifications. The Smart Sock 3rd Generation has a weight limit of about 30 lbs and since every foot is different, some little ones can outgrow the sock sooner than others depending on the roundness of the foot.

Make sure that your sock placement and sock size are correct and that you are rotating the sock from one foot to the other on a nightly basis. 



We recommend placing the sock on a clean, dry foot without any ointments or cream. Our sock doesn’t absorb moisture as well as other socks due to the sensor components and if moisture builds up, it can irritate your little one’s skin, similar to a diaper rash.

If your child tends to get sweaty or clammy feet while sleeping, we recommend ensuring a comfortable sleeping temperature (less warm pj’s, a fan in the room, etc.) and limiting the amount of time they are wearing the Smart Sock. 



If your baby seems uncomfortable due to teething, colic, or just likes to move, the constant movement can cause enough friction to create hot spots on their foot. If the skin is irritated enough, these hot spots can quickly progress into blisters. It’s the same as someone breaking in a pair of new shoes, where the shoe doesn’t match the foot. This causes repeated rubbing and irritation.

If a mark appears, the skin will need time to heal. Rest the foot with the mark on it and don’t put the sock back on that side until the mark has gone away. Help support the healing skin by applying a barrier cream containing petroleum jelly or equivalent several times during the day. When the mark is gone, you can put the Smart Sock back on that side, making sure the sizing and placement are correct. 

If you have any questions about whether your little one is wearing the Smart Sock correctly, please take some pictures from a few different angles, and use our in-app chat feature to talk to one of our skilled representatives. Chat is located in the Accounts menu in the Help and Support category. 


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