Eczema Causes and Symptom Triggers

Medically reviewed by William Truswell, MD

Eczema (atopic dermatitis) is a complex inflammatory skin condition that can occur at any age. It is estimated that 1 in 10 individuals will develop eczema during their lifetime. Prevalence peaks during early childhood (usually before age 6), but adults can develop eczema, too.

It's difficult to pinpoint or isolate eczema causes because a cluster of factors can increase a person's risk, including genetics, environment, allergies, stress, and other conditions. There are many types of eczema. This article discusses the general causes of eczema, triggers, and when to get help.

Primary Causes of Eczema

An interplay between genetic predisposition and environment is thought to cause eczema. Still, the exact cause of eczema is unknown.

Eczema often occurs when a person has an overactive immune system (from internal and external causes). It develops when the outermost skin barrier is broken down, resulting in dry, itchy patches of skin that are red and inflamed. Excessive itchiness results in increased scratching that can lead to skin infections.

Eczema Infections

Eczema is not infectious, but it can lead to skin infections. Open wounds caused by excessive scratching or dry, cracked skin can increase the risk of bacteria and viruses entering the skin and causing infections. There are different types of eczema infections some of which are viral and others of which are bacterial.

Symptoms include swollen, hot skin, dry, yellow crusting, fluid-filled blisters, and open sores. If you suspect that your eczema is infected, your healthcare provider will take a sample of the skin to determine the cause and proper treatment.

Most people have a combination of factors that causes their eczema. Some of these include the following.

Genetics

If you have a family history of eczema, you are more likely to get it. Infants with parents who have allergies or asthma are at the highest risk of developing eczema. Older research suggests that the risk of childhood eczema is two to three times higher in children with a parent who has a history of eczema.

People with eczema often have mutations in the FLG gene, which produces filaggrin. Filaggrin is a protein that helps the body maintain a healthy, protective skin barrier on the outer layer of skin.

Mutations affecting filaggrin can result in a broken or leaky skin barrier, which allows bacteria, viruses, and allergens to enter the body, resulting in itchy skin. Allergens are normally harmless substances that trigger an allergic reaction.

Other genes affecting the development of the skin barrier may also be associated with an increased risk of eczema. These and the FLG gene are part of the epidermal differentiation complex (EDC) grouping of genes.

An Overactive Immune System

People who develop eczema often have an immune system that is dysregulated (not functioning under its usual controls). The dysregulated immune system is associated with increased serum IgE (an antibody generated by the immune system) and allergen sensitization (recognizing an allergen as foreign and producing IgE), and high levels of T-cells (a type of immune system cell) associated with immune and skin function.

Disruptions in these cells and proteins can cause inflammation.

Allergies and Asthma

Children with eczema often have atopic march, a cluster of conditions that usually starts with eczema and can progress to IgE-mediated food allergy, asthma, and allergic rhinitis. Oftentimes, children grow out of eczema. Eczema can be controlled with a good skin care regimen and by avoiding triggers.

If your child has persistent eczema without relief, you can benefit from seeking the help of a pediatric dermatologist and allergist.

Eczema vs. Allergies

Eczema and allergies are associated. Allergens can enter the skin due to a defect in the skin barrier and can cause eczema to get worse. For example, if you are allergic to pollen and it enters your skin, it can trigger an eczema flare-up.

It is recommended that people who have chronic eczema that does not go away despite optimal skin care get tested for allergies. For people or children who have had allergic symptoms after ingestion of food (runny nose, hives), food allergy testing is recommended. If an allergy exists, allergy medication and avoiding that allergen may help to improve symptoms.

Environmental Irritants

Eczema is often associated with environmental allergies (trees, pollen, grass, dust mites, mold). Contact dermatitis is a type of eczema triggered by irritants. It can erupt when skin is exposed to shampoos, soaps, dyes, chemicals, fragrances, metals (nickel), hand sanitizer, wipes, and so forth.

In addition, people who live in an urban environment with increased pollutants are at an increased risk of developing eczema.

Tobacco Smoke

Exposure to secondhand smoke and active smoking is associated with eczema. It is thought that the chemicals in the smoke can break down the skin barrier, allowing allergens to penetrate the skin.

Related: The Link Between Smoking and Eczema

Secondary Eczema Causes

People with eczema may experience skin flare-ups due to weather, extreme temperatures, stress, insufficient sleep, and diet.

Weather and Extreme Temperatures

Extremely cold or hot climates can increase the risk of eczema. People may also see that their eczema worsens during the change of season, dry or humid weather, and at high altitudes. Prolonged hot showers can also dry out the skin, worsening eczema.

Stress

Both physical and mental stress can worsen eczema, and chronic eczema can cause psychological stress. Stress can cause inflammation, which triggers eczema. Managing stress has proved to help improve eczema.

Lack of Sleep

Sleep disturbance is a common symptom of eczema;people often report that their eczema is worse at night. This can impact their ability to fall asleep and stay asleep. Incessant itching can also reduce the amount of sleep and disrupt sleep quality, which can result in inflammation.

Diet

A specific diet doesn't cause eczema. However, exposure to food allergens can cause eczema to flare. For some people, particularly infants and young children, an eczema flare caused by food allergens can cause hives and intense itching.

Some research suggests that probiotics, omega-3 fatty acids, and vitamin D supplements may help improve and potentially prevent eczema. However, before starting yourself or your child on supplements, discuss it with your healthcare provider or pediatrician.

Related: What to Eat When You Have Eczema

Are Triggers Different From Eczema Causes?

The short answer is yes. However, it is complex. Triggers don't necessarily cause eczema, but they can worsen eczema or cause flares in people who have a genetic predisposition, immune system dysregulation, and a breakdown in the skin barrier.

Everyone's triggers are different. For example, heat and sweat can trigger eczema flare-ups in people who already have eczema. Therefore, people with eczema may need to take some additional actions to prevent flare-ups during exercise.

Related: A Guide to Exercising With Eczema

Identifying your triggers may reduce eczema flares and symptoms. A healthcare provider or allergist can rule out allergens and sensitivities.

When You Can’t Figure Out Eczema Causes

Eczema is a chronic skin condition, and symptoms can come and go. Nearly anything can trigger eczema, from stress to the environment, making it difficult at times to identify the cause. Whether you're experiencing eczema for the first time or have had it for many years, your triggers can change.

Keeping a log or journal of when you experience eczema as well as your symptoms can help you identify your triggers. For example, if your eczema flares after doing laundry, you can change your detergent and see if that makes any difference. Sometimes, there is a lag time between exposure and reaction, making identification difficult.

In certain instances, you may not be able to identify your trigger. Or even after removing it, you still cannot seem to get your eczema under control. If this is the case, reach out to a healthcare provider. They can help you to identify the cause and produce a treatment plan.

If your eczema is severe, you may need some short-term topical medicines, along with a good maintenance skin care routine, to get your eczema under control.

Summary

Eczema is a complex, chronic inflammatory skin condition that causes dry, itchy skin. People with eczema are often genetically predisposed to the disease and have some sort of immune dysregulation. Eczema is also associated with other conditions, like asthma and allergies.

While everyone's triggers are different, identifying and managing your own can help you to find some relief. However, if you are unable to figure out what is causing your eczema or making it worse, you should get a medical evaluation. A trip to the dermatologist or allergist may be necessary so that you can produce a tailored plan that allows you some relief.