While Breastfeeding: Early Signs of Allergies in Babies

baby feet wrapped in pink blanket

This is the sixth installment in our series on reducing your baby's allergy risk. If you missed the fifth installment, read it here, or jump back to the During Pregnancy or the First 24 Hours installments. 

How do you know if your baby has allergies? In this lesson, we go over the early signs of allergies in babies, and what you should keep an eye out for.

Eczema, asthma, seasonal allergies (rhinitis), and food allergies are the most well-known manifestations of allergic disease. Together, the tendencies to have allergic reactions is called atopy. 

While some can have just one of these conditions, many babies will develop multiple, and they will happen in a particular order. This pattern of developing multiple forms of allergic disease is called “the atopic march”. 

As the metaphor of a march suggests, there is a sort of progression from one allergy to another as a baby is exposed to triggers and as their immune system matures. 

There is no official data on the exact moment these issues develop, but the image below is a proposed model of how the march progresses.


atopic march allergy progression


Eczema is likely to present itself early in a baby’s life, with food allergies, asthma, and seasonal allergies (rhinitis) developing as a person ages.

Here we’ll discuss early signs of each of the common forms of atopy. Always consult your pediatrician if you are concerned your child is developing issues. 


Atopic dermatitis, or allergic eczema, is often thought to be the first disease that presents in babies. 

Two early signs of eczema are allergic shiners and trans-epidermal water loss.

Allergic shiners look like eye circles or bags under a baby’s eyes — almost like your little one took up boxing (hence the name “shiners”). These shiners are swelling and discoloration from congestion of small blood vessels beneath the skin in this area. 

Have your child evaluated by their pediatrician for eczema and hay fever if you seen allergic shiners on a regular basis.

Trans-epidermal water loss (TWEL) is in many ways a fancy way of saying dry skin. As discussed when talking about your baby’s skincare routine, water loss leaves your baby’s defense barrier weak and prone to infection. 

There are new ways to measure water-loss from skin using a small probe. There are multiple Portable Skin Moisture Analyzers on the market, and while they’re not a staple in doctor’s offices yet, a tool like this can help your doctor understand what you are seeing. 

If you’re not sure if your baby’s skin condition is the start of eczema, this tool may also be helpful for you and your pediatrician to track changes in your baby.

Food Allergy

Food allergies can be hard to identify in infants who have not yet started eating solids because they’re only trace amounts of food through their mother’s breastmilk. For example, only about 30% of women express peanut protein in their breastmilk, and it’s always in tiny amounts. 

Food allergies are also hard to identify because infants under 6 months only have skin reactions or stomach issues when reacting to a food. The skin reactions can look at lot like eczema, and the stomach issues can look at lot like standard spit up. 

If your baby...

  • Consistently vomits after feeding
  • Has bad smelling poops (2 month old’s poop should smell sweet)
  • Has bloody or mucous-y poops
  • Fails to gain weight
  • Has severe stomach pain...

immediately see your pediatrician for concerns of food intolerance or allergy. Your pediatrician may ask you to cut food out of your diet if you are breastfeeding or switch to a hypoallergenic formula to see if it clears up the issues. They may also order skin or blood tests to look for sensitization to foods.

Hay Fever / Asthma

As described in the atopic march image above, babies typically do not develop asthma or seasonal allergies until they are toddlers or older. See your pediatrician to rule out allergic causes if you are ever concerned that your baby is having congestion, trouble breathing, or cold-like symptoms that do not resolve. 


What would you like your pediatrician to talk about that you think is being skipped? Leave a comment below!