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

Worldwide, 15–30% of children and 10% of adults have had a diagnosis of AD.

Despite its prevalence, the causes remain somewhat unclear. Research, which we explore below, points to a combination of factors, including genetic and the environmental factors.

Recently, a growing body of research has indicated that gut health and the gut microbiome may affect the development of AD. 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 important functions, including immunity and allergic reactions.

A 2021 review of studies 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.

Here, we look at how interactions between the gut and skin may lead to AD. We also explore what researchers have found 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.

Other research from 2021 shows that people with inflammatory skin diseases, including AD, acne, eczema, and psoriasis, often have a microbiome that is not well balanced.

Changes in the composition of the microbiome is called dybiosis, and dybiosis is linked to changes in immune response that may lead to the development of skin diseases.

Meanwhile, skin issues such as AD 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 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. Feeding styles and delivery method may also influence the microbiome and prevent a healthy balance of microbial populations.

Researchers have found that an imbalance in bacterial populations in early life is associated with the age at which a person develops AD. It can also affect the severity of the condition, the frequency of flares, and the likelihood of it going into remission.

This may indicate that infants and children with less gut microbial diversity may be more susceptible to AD and other inflammatory skin conditions, though confirming this will require further research.

It is also possible that interactions between nonbacterial gut microbes and the immune system may lead to the development of AD.

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. Probiotic supplements may improve gut health, but research so far has not confirmed this.

It remains unclear whether restoring a healthy microbial composition is the only gut-related intervention that may help improve AD symptoms. Future studies will investigate whether probiotic supplements have a positive effect on AD.

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

However, as yet, 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:

  • Eat more fiber. Evidence suggests a diet rich in fiber is associated with greater diversity of gut bacteria. High fiber foods include beans, vegetables, fruit, whole grains, seeds, and nuts.
  • Eat fermented foods. These contain live bacteria and other microbes. Fermented foods include yogurt, kimchi, kombucha, sauerkraut, and tempeh.
  • Manage stress. Stress negatively effect the body’s bacterial populations. A therapist or counselor may be able to help by providing exercises and guidance for better stress management.
  • Drink less alcohol, if any. Alcohol can negatively affect the gut microbiome. Drinking too much can lead to dysbiosis, which is implicated in several health issues, including AD.

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

Some researchers believe that taking probiotic supplements may help prevent AD or help ease the symptoms. However, investigations so far have been unable to verify this, and 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, for those who drink it.