The exact cause of eczema is unclear, but genetic changes, problems with the immune system, and exposure to environmental triggers may all contribute to the development of the skin condition.

Research indicates that eczema affects roughly 1 in 5 children and about 1 in 10 adults. Eczema normally refers to atopic dermatitis, which is a chronic skin condition. It causes inflammation, resulting in dry and itchy skin. The skin may also weep clear fluid when scratched.

Genetic and environmental factors may have a role in the development of eczema. While anyone can develop eczema, research suggests that people with allergies, asthma, and eczema themselves are more likely to have children who develop eczema.

In this article, we will explore whether eczema is hereditary, which genes it involves, and how eczema occurs.

A parent and their children, who may inherit eczema.Share on Pinterest
Jessica Klaus/Stocksy

Anyone can develop eczema. However, if it runs in a person’s family, the likelihood of developing it increases. A 2015 study found that the chance of inheriting eczema is approximately 75%.

Genes carry the genetic information that contains instructions to make proteins. Every person will have two copies of each gene, one from each parent. A person may inherit mutated genes from one or both of their parents, which increases their chance of developing eczema.

While researchers do not fully understand the genetics of eczema, evidence suggests that several genes may contribute to the development of the condition, and, in rarer cases, a single inherited gene mutation may lead to eczema.

One such gene is CARD11, which carries the information to make a protein that is necessary for the proper functioning of lymphocytes. Lymphocytes are immune cells that protect the body from infections.

Mutations in the CARD11 gene can result in atopic eczema due to a weakened immune system. Researchers have identified at least five CARD11 mutations that may be present in people with atopic eczema.

A 2017 study found that a mutation in one copy out of the two inherited CARD11 genes was enough to cause atopic eczema.

Another gene that plays a role in the development of eczema is KIF3A, which codes for a protein involved in protein binding and transport. A 2020 study found that genetic variation in KIF3A may increase the risk of developing atopic eczema. This is due to the skin barrier becoming weakened and water loss from the skin.

Another gene that may contribute to the development of eczema is FLG. This gene codes for profilaggrin, which produces the protein filaggrin. This protein plays a role in the maintenance of the skin barrier and skin hydration.

There is a strong association between mutations in the FLG gene and the development of atopic eczema. Between 20–30% of people with eczema have an FLG gene mutation. Researchers have identified 40 FLG mutations in people with eczema. Eczema is usually more severe in people who have mutations in both copies of the FLG gene.

Eczema affects an estimated 30% of the U.S. population. Eczema normally manifests before the age of 5 in 70% of cases. It is currently unknown what exactly causes eczema. However, researchers believe that a combination of genes and environmental triggers is responsible.

A person may inherit mutated genes from their parent or they may acquire a gene mutation throughout their lifetime. A person may have a gene that increases their likelihood of eczema, but that gene may not be active until they become exposed to an environmental factor.

Environmental and biological factors can also cause eczema. For example, stress or smoking tobacco are among the things that can cause a type of eczema called dyshidrotic eczema.

Other factors that may increase the risk for eczema include:

  • air pollutants
  • water hardness
  • tobacco smoke exposure
  • diet
  • alcohol consumption
  • living in an urban setting

Click here to learn more about the different types of eczema.

Eczema is not contagious. This means that a person cannot acquire eczema from being in contact with someone who has the condition.

However, due to the cracking of the skin that eczema causes, a person with eczema can be more vulnerable to infections. Skin infections are common in people with eczema and these infections can be contagious.

For example, people with atopic eczema are at a higher risk of developing eczema herpeticum. This is an infection that can be caused by the herpes simplex 1 (HSV-1) or herpes simplex 2 (HSV-2) virus. It results in blisters on the skin which may weep or bleed. Eczema herpeticum is contagious.

Learn more about eczema herpeticum.

Here are some questions people often ask about eczema’s genetic link.

Is eczema hereditary or genetic?

People with eczema appear to have changes in specific genes, such as the CARD11 gene. This may make a person more susceptible to developing eczema in certain circumstances. Some of these genetic changes may be inherited, and there is some evidence that eczema runs in families. However, more research is needed.

Does eczema run in families?

People appear more likely to develop eczema if there is a family history of eczema, hay fever, or asthma. This suggests it may run in families, although research is ongoing.

Are you born with eczema or can you develop it?

A person may inherit or be born with a genetic feature that makes them more likely to develop eczema, but they may never develop it. However, having this feature can increase the likelihood of developing eczema later in life if exposure to a trigger — such as air pollution — occurs.

Scientists are still learning more about eczema, but evidence suggests there is a genetic predisposition and that eczema may be hereditary. Researchers have identified that mutations in the KIF3A, FLG, and CARD11 genes are commonly associated with the development of eczema.

Other factors can also cause eczema. For example, environmental triggers such as air pollution and tobacco smoke and biological factors such as stress can also result in eczema.