There are two things that can cause eczema.
In some cases, an allergy to pollen, mold, or milk, may cause an immune system reaction that causes itching and red skin.
In more cases, the skin, which is your body’s protective wall, gets cracked. This breakdown of the skin barrier causes the immune system to rev-up to protect you, and you feel it as itchy skin.
About 1 in 8, or 13% of babies develop eczema. Eczema usually first shows up when a baby is between 3 and 6 months old, and almost all (85%) eczema will begin during the first year of life. Many children with eczema will outgrow it, with chances increasing 5, 10, and 20 years from onset.
Allergic Causes of Eczema in Infants
Eczema can be a sign, usually the first sign, of a malfunction in the immune system. Instead of ignoring harmless substances like pollen, food, and dust, the immune system releases histamines that cause itchiness when it comes into contact with these things. This is a kind of allergic reaction.
That is why antihistamine medications like Benadryl and Zyrtec can control eczema for some people. Most often in babies, pet dander, pollens, or mold cause this histamine response.
Food allergies can sometimes cause eczema. Dr. Peter Lio, Assistant Professor of Dermatology and Pediatrics at Northwestern University and Founding Director of Chicago Integrative Eczema Center, spoke to the National Eczema Foundation and said that, “there is a group of people who have food reactions that look like an eczema flare-up rather than specific hives, and can take days to manifest.”
The only way to determine if a food allergy is the cause of eczema is to remove the food and see if symptoms heal. In babies, cow’s milk allergy is the biggest culprit. In older children, it can be soy or wheat.
If you believe a food allergy may be the cause of your baby’s eczema, discuss with your pediatrician how to safely try an elimination diet.
Skin Barrier Dysfunction Cause of Eczema in Infants
The other cause of eczema is a defective skin barrier. Some people have a genetic mutation where their body doesn’t produce a key protein called filaggrin. This protein is what makes the skin soft and springy. Filaggrin also helps prevent excessive water loss through the skin.
This leads to the dry, cracked, itchy skin we know as eczema.
Other people may have a less healthy skin microbiome. Having the right microbes on your skin can help create and enhance its strength. The outermost skin wall is made of dead cells (brick) and ceramides (mortar). Humans don’t make their own ceramides, the bacteria do. With the wrong bacteria, you can lose the mortar, causing cracks in the skin, which allows bad bacteria like staph A to infect the skin.