The most common type of eczema is atopic dermatitis. Atopic dermatitis has several related conditions. One common set is called the “atopic march” because the conditions typically come on step-by-step in a certain order.

Food Allergies

About 15% of children 3 to 18 months old with atopic dermatitis will have a food allergy. The most common allergies are:

• Peanuts
• Milk
• Wheat
• Soy
• Eggs

Symptoms include itchy mouth and swelling lips, vomiting and diarrhea, hives, and a sudden drop in blood pressure.

In the “atopic march,” food allergies are often the next step after eczema.

Asthma and Allergic Rhinitis

Asthma makes it hard to breathe. When you have an asthma attack, your airways swell and narrow. About 20% of adults who have atopic dermatitis get asthma.

Allergic rhinitis, commonly called hay fever, is set off by things like pollen, dust, and pet dander. Symptoms include:

• Itchy or watering eyes
• Sore throat
• Sneezing
• Stuffy or runny nose

For years, experts have puzzled over the reasons these conditions are linked. You may just be born with a higher chance of overreacting to certain substances. That’s called “atopy,” and your genes play a role. Elements in your environment are also a factor.

Researchers are looking into whether eczema may help cause these conditions. Your skin is a barrier for your body. When eczema damages that barrier, it can set off a reaction that opens the door for future reactions.

Allergic Contact Dermatitis

Contact dermatitis is an irritation that happens after your skin touches something that sets it off. When you have allergic contact dermatitis, this reaction is delayed. You get a rash within a day or two, after your body’s immune system responds.

Experts have several theories on the link between eczema and allergic contact dermatitis. Skin damage from eczema weakens your body’s defenses. This makes you more vulnerable to irritating substances, and your body’s response may ramp up. When you use topical medicines, including those that contain steroids, you also might make your body more sensitive.

Depression and Anxiety

Many studies have linked eczema and mental health issues, both in children and adults. Research shows when eczema is treated properly, mental health improves. That suggests the severity of eczema and mental health problems are tied.

People with eczema may be socially isolated, feel singled out because of their condition, and be unhappy with the quality of their lives. Sleep problems, which are common with eczema, can also play a role in depression and anxiety.

Your body’s inflammatory response to eczema may also play a role in mental health. Scientists are still doing research to find out more.