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Does your child have eczema, a chronic, red, itchy skin rash? Do you or your spouse suffer from seasonal allergies or asthma? Or did you have eczema as a kid and now suffer from hay fever as an adult? If so, it's no coincidence.

Studies show that if one or both parents have eczema, asthma, or seasonal allergies, their child is more likely to develop the most common type of eczema, atopic dermatitis. What's more, children with eczema may be more at risk for developing allergies or asthma. In fact, one study found that 35% of adults who had eczema as children had hay fever or asthma as adults.

Whether you or your child has this itchy skin rash, understanding the allergy-eczema connection can help you manage the disease. Here's what you need to know about the link between allergies and eczema.

What Is Eczema and Who Gets It?

Eczema is the term for several different skin conditions. However, eczema most often refers to a common skin disease called atopic dermatitis, which causes a dry, itchy, red rash. Scratching the rash can cause it to ooze and crust over. Chronic scratching can cause the skin to thicken and darken in color.

About one in every 10 kids develops eczema. Most get eczema as infants, and 90% get it before age 5.

In most children, symptoms often improve by age 5 or 6. Once children hit their teenage years, more than half no longer have eczema flare-ups. However, many people continue to have eczema as adults, although symptoms tend to be milder. Less often, eczema first develops in adulthood.

The Eczema-Allergy Connection

Most types of eczema are not allergies. However, many people with eczema have flare-ups when they are exposed to allergens.

An allergic reaction occurs when the body's immune system overreacts to substances that are usually not harmful. These include allergens such as:

  • Dust mites
  • Pollen
  • Animal dander
  • Certain foods

When exposed to an allergen, the body attacks and releases histamines. These chemicals cause an allergic reaction in the form of hives, itching, swelling, sneezing, and runny nose. Children with eczema are also more likely to have food allergies, such as to eggs, nuts, or milk. Food allergies often make eczema symptoms worse in children but not in adults.

Research Into Eczema and Allergies

The eczema-allergy story still isn't fully understood. At one time health experts thought that all types of eczema were caused by allergies. Now we know that the connection is more complicated. Researchers continue to uncover new insights about the causes of eczema that may lead to better treatments. Some recent areas of study include:

Genetic factors. Researchers have found that some people with eczema have a genetic defect that causes a lack of filaggrin in the skin. Filaggrin is a type of protein that helps form the protective outer layer of our skin. This skin barrier protects the body from germs and other foreign substances. A lack of filaggrin dries out and weakens the skin barrier. This makes skin vulnerable to irritants such as soaps and detergents. A weak skin barrier also makes it easier for allergens, such as pollen, to enter the body. Scientists believe that this exposure may cause the sensitivity to allergens and even certain foods.