Atopic dermatitis (AD), or eczema, is a common, chronic inflammatory skin condition. Changes in the populations of microorganisms in the gut may play a role in developing AD.

Despite its prevalence, the causes of AD remain somewhat unclear and may involve a combination of factors, including genetic and environmental factors.

Recently, a growing body of research has indicated that gut health and the gut microbiome may affect AD’s development. In other words, what happens in the gut may determine what happens on the skin.

A person’s microbiome is the collection of bacteria, yeasts, and other living organisms in and on their body. It plays a significant role in overall health. The microbiome has strong connections to certain functions, including immunity and allergic reactions.

This article explains how interactions between the gut and skin may lead to AD, including what research suggests about reversing AD with better gut health.

Skin is home to trillions of living microscopic organisms. Trillions more of these bacteria, yeasts, fungi, and other organisms live elsewhere in the body, primarily in the gastrointestinal system.

The gut and the skin interact in complex ways, and a health issue affecting one can affect the other. Researchers refer to this network of interactions as the gut-skin axis.

A 2021 review suggests people with inflammatory skin diseases, including AD and other types of eczema, acne, and psoriasis, often have a microbiome that is not well-balanced.

Changes in the composition of the microbiome are called dysbiosis. The review authors associate dysbiosis with changes in immune response that may lead to the development of skin diseases.

Meanwhile, skin issues such as eczema can be itchy, and scratching the skin can destroy its natural barrier. This can upset the immune response and alter the body’s microbial environment.

As a 2018 study notes, the key to understanding the gut-skin axis is to understand how the two body systems communicate and what connections they have to conditions such as AD. For now, however, many of those connections remain unclear.

Research in a 2021 review suggests 15–30% of children and 10% of adults worldwide have a diagnosis of AD. The exact causes of the condition are unclear but may involve genetic, environmental, and immune factors.

A 2024 narrative review suggests the following gastrointestinal disorders may be more common among people with atopic dermatitis:

  • food allergies or sensitivities
  • Crohn’s disease
  • ulcerative colitis
  • celiac disease
  • irritable bowel syndrome (IBS)
  • gastroesophageal reflux disease (GERD)

The 2021 review also suggests that changes in the microbiome may lead to AD. Addressing these changes and restoring the balance of the microbiome may support better skin health.

AD development

Research from 2018 indicates that the gut microbiome may play a role in developing AD. Dysbiosis, or changes in the body’s microbial composition, may occur early in life and increase the risk of AD.

AD is more common in infants and children than adults. This may be because a child’s gut microbiome is less able to fight off harmful bacteria, for example.

A 2023 literature review suggests feeding styles and delivery method may also influence an infant’s microbiome and prevent a healthy balance of microbial populations.

It suggests infants born by vaginal delivery who are breastfed have a more diverse microbiome than those born by cesarean section who are formula-fed.

An imbalance in bacterial populations in early life may affect the following aspects of AD:

  • age of onset
  • severity
  • frequency of flares
  • likelihood of remission

Further research is necessary to fully understand the interactions between AD and the gut, including how this connection may influence treatment.

Researchers believe that changing the composition of microbes in the gut may improve skin conditions such as AD.

Probiotics — bacteria, fungi, and yeasts that are beneficial to gut health — can influence the composition of bacteria in the digestive tract and on the skin.

A 2022 meta-analysis suggests that probiotics may help to improve disease severity and quality of life for people with AD.

However, more research is necessary to understand whether restoring a healthy microbial composition is the only gut-related intervention that may help improve AD symptoms.

People with inflammatory conditions such as AD may have a low diversity of gut bacteria. There may be an overpopulation of harmful bacteria.

However, so far, no research indicates how to tailor a probiotic diet to treat a specific health condition.

Instead, one can focus on supporting overall gut health by fostering a stronger community of beneficial bacteria. Diversifying the gut’s bacterial community in this way may boost overall health.

Tips for fostering a healthier gut microbiome include:

  • Eating more fiber: A 2021 article associates a diet rich in fiber with greater diversity of gut bacteria. High fiber foods include beans, vegetables, fruit, whole grains, seeds, and nuts.
  • Eating fermented foods: These contain live bacteria and other microbes. Fermented foods include yogurt, kimchi, kombucha, sauerkraut, and tempeh.
  • Managing stress: Stress can affect the body’s bacterial populations. A therapist or counselor may be able to help by providing exercises and guidance for better stress management.
  • Avoiding or reducing alcohol consumption: Alcohol can reduce gut microbiome diversity. Drinking too much can lead to dysbiosis, which may contribute to health issues, including AD.

The specific causes of AD are unclear, but research indicates that the gut may play a role. Low levels of microbial diversity and an imbalance in bacteria populations may contribute to the onset of AD, even from an early age.

Some researchers believe that probiotic supplements may help prevent AD or ease its symptoms. However, further research is necessary.

There are several ways to foster a healthier gut microbiome, including eating more fiber and fermented foods, managing stress better, and drinking less alcohol.