But a new, small study offers insight that may help healthcare providers identify and more effectively treat those children with eczema (atopic dermatitis) and food allergies. For the study, published in the February issue of Science Translational Medicine, researchers used a noninvasive skin tape test to analyze skin abnormalities in these patients, effectively identifying a subtype of eczema patients that are prone to food allergies. “Babies and children don’t like tests that hurt,” says lead study author Donald Leung, MD, PhD, head of the division of pediatric allergy/immunology at National Jewish Health. “We believe eczema and food allergy abnormalities are in the top layer of skin, so we can measure proteins and lipids in the top layer of skin and actually tell a difference in the skin from people who don’t get eczema.” RELATED: What Are the Symptoms of Eczema and How Is It Diagnosed? Eczema is a chronic, noncontagious skin disease most commonly treated with topical corticosteroids. Atopic dermatitis is the most prevalent type of eczema, and it results from skin barrier problems and a malfunctioning immune system. Healthcare providers and patients alike commonly use atopic dermatitis and eczema interchangeably. Eczema affects 17 to 24 percent of children, according to a study published in June 2017 in The Journal of Allergy and Clinical Immunology. It’s often linked with other allergies, including food allergies, allergic rhinitis (hay fever), and asthma. Previous research shows that about 30 percent of children with eczema develop food allergies. “If we knew who was at high risk, we could straightaway make sure to do everything we could to prevent it in the first place or test for those food allergies very early,” says Abigail Waldman, MD, a dermatologist at Brigham and Women’s Hospital in Boston and an instructor of dermatology at Harvard Medical School. Dr. Waldman was not involved in the study. RELATED: How Do Food Allergies Affect Digestion?
What Makes the Skin of Kids With Eczema and Food Allergies Different?
Researchers analyzed the skin of 62 people ages 4 to 17, whom they organized into three groups: those with normal skin, those with eczema, and those with eczema and a food allergy. At the time they took the skin samples, the skin of those participants with eczema was not inflamed. They observed that skin samples of participants with eczema and food allergies had significant differences from the other two groups. These abnormalities included a lack of structural proteins required to keep moisture in and provide a barrier for skin, an increase in specific keratin proteins that are a sign of an underdeveloped skin barrier, and an increase in activity of type 2 immune genes, the gene response that causes allergies. If you think of the protective outer layer of your skin like a brick wall, the skin cells are the bricks and the proteins and lipids are the mortar. If there are cracks in the cement, pathogens and bacteria can get in and water can get out. “With eczema, when you flex your hands or bend the skin, the skin cracks and starts bleeding, and you lose water from the skin, making it [drier]. Then things come in because it’s all cracked. It’s inside out, outside in,” Dr. Leung says. The study focused on patients with a peanut allergy. Researchers are further investigating their data to study other food allergies. Common food allergies include eggs, wheat, soy, shellfish, and milk, according to the organization Food Allergy Research & Education (FARE). RELATED: How Eczema and Diet Are Connected
How the Study Findings May Help Babies Avoid Food Allergies
The participant group of the study was small, but Leung says the team plans to study larger groups with the aim of making new treatment recommendations. The next step is to study infants from birth. When an infant is born, he or she goes from being in a wet environment (the mother’s womb) to a dry one. This transition can damage the infant’s skin barrier, causing eczema. Leung plans to study infants from birth to try to figure out when these skin abnormalities develop. That way, doctors would be able to treat those who may be prone to eczema and food allergies early on. The skin samples from the study that showed abnormalities were from nonirritated skin. “This is important because we believe the changes in the skin occur before you get a food allergy,” Leung says. “There’s a window of opportunity for you to treat skin and prevent food from invading through the skin.” As for the ideal treatment to protect babies with eczema from developing food allergies, Leung says the team needs to do further research, but some existing emollients may be useful. “It could be as simple as Vaseline around the lips to cause grease, which prevents food from going through the skin, or it may be applying certain lipids or fatty acids missing from their skin that could enhance skin development so it’s stronger,” he says. RELATED: How Reducing Indoor Allergens Can Ease Your Eczema Symptoms
A Noninvasive Test May Hold the Key to Identifying Eczema Subtype
One advance of the study, Leung says, is the noninvasive, painless testing method. Researchers used a mild skin tape — similar to the sticky part of a bandage — to remove the superficial top layer of skin. The method has long been used for research but for simpler tests. “What’s interesting is that researchers were able to do a lot of very sophisticated analysis from few skin cells,” Waldman says. The method provides an alternative to more painful biopsies and blood tests, which Waldman says are rarely used because children and parents don’t want to undergo them, and because usually by that point in the eczema progression, a blood test won’t necessarily help. “It’s declared itself at that point,” Waldman says, adding that the implications of this study are promising, but more research is needed. “The paper definitely shows a benefit for the future, but I need to stress, it’s not something that should be done in a clinic tomorrow.”
