Eczema, itching and rashes – what role can the gut play?

Perhaps you’ve tried moisturizer after moisturizer, cut out milk, tried cortisone cream – and yet your skin keeps coming back with itching and red patches. It’s natural to ask: could this be coming from within? Here, we take a closer look at the connection between the gut, food and skin – and what is actually supported by evidence.

Paulina Borkowska

Clinical Nutritionist · clinical experience in nutrition and digestive health

13 min read

“I’ve applied cream to my skin every single night for six months. Sometimes it gets better. Then it comes back – just when I least expect it.”

“The doctor said it was eczema and gave me cream. It helped a little. But no one asked about my stomach – and I’ve had bloating for years.”

Do you recognize yourself in either of these statements? You’re far from alone. Many of the women and men we speak with at the clinic have exactly this combination: skin that won’t calm down, and a stomach that isn’t quite settled either. It’s no coincidence that these two are connected for many people – but it’s also not true that the gut is “to blame” for all eczema. Let’s look at what we actually know.

Your skin as a mirror of what’s happening inside

The skin is the body’s largest organ – and it is far from isolated from the rest of you. It is affected by hormones, sleep, stress, the immune system and nutritional status. When your skin reacts with itching, redness or dryness, it’s a signal that something in this overall picture is out of balance. Sometimes it’s purely a matter of the skin itself. At other times, the skin is where a broader imbalance first becomes visible.

This is what makes eczema so individual: two people can have exactly the same rash and still have completely different underlying contributing factors. That’s why the aim of this article isn’t to give you one answer, but to show you the mechanisms worth knowing about – so you can recognize what may apply to you.

The skin barrier: the first line of defense

Before we talk about the gut, it’s worth understanding the skin on its own terms. The outermost layer of the skin – the skin barrier – works a bit like a brick wall: skin cells are the “bricks,” and fat (lipids) between the cells is the “mortar” that keeps everything sealed. When this barrier is intact, it keeps moisture in and irritants, allergens and microbes out.

In eczema (atopic dermatitis), it is well documented that this barrier is often weakened – sometimes for genetic reasons, and sometimes made worse by a dry climate, frequent washing with soap, allergens or irritants. A weakened barrier lets irritants in more easily and moisture out more readily, creating the itch-scratch cycle so familiar to many people with eczema.

The gut-skin axis: how are they connected?

“Gut-skin axis” is a term researchers use to describe communication between the gut and the skin – through the immune system, the microbiome and low-grade inflammation. Around 70% of our immune system is associated with the gut. When the gut’s immune regulation and microbial balance are affected, the ripple effects can reach all the way to the skin.

This doesn’t mean that all skin problems come from the gut. It means that the gut is one of several factors that can affect how much “background noise” your immune system has to deal with – and, in turn, how reactive your skin is.

What does “increased intestinal permeability” mean?

You may have heard the expression “leaky gut.” It’s often used imprecisely, so let’s be precise: the gut wall has natural, regulated “gates” (tight junctions between cells) that control what passes through to the rest of the body. With increased intestinal permeability, this regulation is less precise than normal.

It is an oversimplification – and inaccurate – to say that “undigested food leaks straight into the bloodstream.” What research actually describes is that a less precise gut barrier can increase contact between gut contents (such as bacterial components, for example LPS) and immune cells in the gut wall. This can contribute to greater low-grade activation of the immune system – which in turn can affect how much inflammatory activity your body is primed for, including in the skin.

Food and eczema: allergy, intolerance or something else?

“Is it something I’m eating?” is often the first question people ask themselves. The answer is: it could be – but “reaction to food” is an umbrella term for several very different mechanisms, and it’s important to distinguish between them before removing anything from your diet.

Because these mechanisms are so different, it’s rarely a good idea to cut out “everything suspicious” at once. That means you lose the chance to see what actually made a difference – and risk an unnecessarily restrictive diet. To understand the difference better, read our article about food allergy or food intolerance.

Gluten and milk – what do we actually know?

Gluten and milk are among the most talked-about “culprits” behind skin problems – but the picture is more nuanced than “cut them out and see.” In celiac disease, the connection with skin symptoms (such as dermatitis herpetiformis) is well documented, and a strict gluten-free diet is a medical necessity, not a choice. With NCGS, some people find that their skin and digestion settle on a gluten-reduced diet, even without celiac disease or an allergy. With milk, it’s most often either a true allergy to milk protein or lactose intolerance (which primarily causes digestive symptoms, not skin symptoms) – the two are often confused.

Histamine: an often-overlooked piece of the puzzle

Histamine is a signaling substance involved in itching, redness and swelling of the skin, among other things. Some people have a lower capacity to break down histamine from food (including through the DAO enzyme), which can cause symptoms such as itching, rashes, headaches and a racing heart after eating histamine-rich foods such as aged cheese, red wine, cured meats and pickled vegetables. It’s worth exploring if your itching clearly fluctuates with certain meals. Read our more detailed overview in our article about histamine intolerance.

The microbiome: diversity and balance

Your gut is home to trillions of microorganisms, collectively known as the microbiome. A diverse and balanced microbiome helps train and regulate the immune system. Research has linked lower diversity in the gut flora early in life with a higher incidence of atopic eczema later on – but these are statistical associations at the group level, not a guarantee that an imbalance in your microbiome is the cause in your case.

What we can say with reasonable confidence: an imbalanced microbiome (dysbiosis) is rarely the only explanation, but it may be a contributing factor alongside diet, sleep, stress and the condition of the skin barrier.

Constipation and slow digestion

When bowel movements aren’t regular, gut contents remain in the intestines longer than necessary. This can put more strain on the intestinal lining and affect how the body eliminates waste products through the liver and gut. Several of the patients we see with skin problems also have sluggish digestion that they’ve barely considered “a problem” – because they’ve become used to it. If this sounds familiar, it may be worth assessing your digestion more systematically before focusing solely on your skin. Read more in Struggling with digestive problems? New Norwegian method identifies the cause.

Nutrients your skin depends on

Your skin is constantly renewing itself, and this renewal requires building blocks. Protein provides the amino acids that collagen and keratin are made from. Essential fatty acids are part of the barrier structure itself. Zinc is involved in wound healing and inflammation regulation. Vitamins A, C, D and E, as well as B vitamins and copper, each play a role in maintaining healthy skin.

It’s important to be honest here: no single deficiency “causes” eczema on its own, and there is no one vitamin that solves the problem. What is documented, however, is that a broad and adequate supply of nutrients gives the skin better conditions for repairing itself and maintaining its barrier function.

Zinc and copper: a balance, not a single nutrient

Zinc gets a lot of attention when it comes to skin, and for good reason – it is involved in inflammation regulation and tissue repair. But zinc and copper compete for the same absorption pathway in the gut. Long-term, high-dose zinc supplementation without copper alongside it can weaken copper status over time, which can itself cause new symptoms. That’s why we recommend considering these two minerals together, not in isolation – and preferably consulting a clinician if using them for an extended period.

Omega-3 and omega-6: a balance, not an enemy

Omega-6 fatty acids often get a bad reputation when it comes to skin, but they are not “dangerous” – they are a necessary part of the skin’s lipid barrier, including through linoleic acid. For many people on a modern diet, the challenge isn’t that omega-6 is present, but that the balance between omega-6 and omega-3 can easily become skewed, with relatively little omega-3 from oily fish, shellfish and krill.

The omega-3 fatty acids EPA and DHA are building blocks for signaling substances that help regulate the body’s inflammatory response. A better balance between omega-3 and omega-6 may therefore be a relevant part of the picture for skin affected by chronic low-grade inflammation – as a supplement to, not a replacement for, appropriate skincare and any medical treatment.

Krill oil and cellular energy production

One way to increase your omega-3 intake is through krill oil. Krill oil differs from regular fish oil in that its fatty acids are largely bound to phospholipids – a form the body can readily absorb and incorporate into cell membranes, including skin cells. Krill oil also naturally contains astaxanthin, an antioxidant that helps protect fatty acids from oxidation.

The table is a general comparison of krill oil and fish oil as sources of fatty acids, and does not claim that either one cures or prevents skin conditions.

PureNordic Mitochondria: energy and fatty acid formula with krill oil

Our Mitochondria formula is built around omega-3 from krill oil (EPA and DHA), combined with ubiquinol (the active form of Q10), R-alpha-lipoic acid, astaxanthin and other supportive ingredients. The formula was primarily developed to support cellular energy production – but because the krill oil component provides the same omega-3 fatty acids mentioned above, it may also be relevant as part of a holistic approach to omega-3/omega-6 balance.

PureNordic

Mitochondria Energy Formula – drops

Krill oil (EPA/DHA), ubiquinol Q10, R-alpha-lipoic acid and astaxanthin in drop form.

599 kr View product

External skincare – just as important as what happens inside

Regardless of what may be contributing from within, good external skincare is a cornerstone of managing eczema and dry, irritated skin. Look for a moisturizer containing both humectants (such as glycerin or hyaluronic acid) and barrier-replenishing ingredients (such as ceramides, shea butter or squalane). Avoid heavily fragranced products and showering too often or with water that’s too hot, as both can further weaken the barrier. Apply moisturizer while your skin is still slightly damp for better absorption.

A diet that supports your skin

You don’t need a long list of forbidden foods to support your skin through your diet. Instead, focus on what you can add: a varied intake of vegetables for fiber and antioxidants, good sources of protein at every meal, oily fish or shellfish a couple of times a week, and healthy fat sources such as olive oil, nuts and avocado. This kind of eating pattern supports both the gut microbiome and the building blocks your skin needs – without requiring you to eliminate entire food groups “just in case.”

When your digestion itself needs support

If you also have bloating, irregular bowel movements or discomfort after meals alongside skin problems, it may be worth taking a closer look at the digestive process itself – not just what you eat, but how well you break it down and absorb it. This is exactly why we developed Digestive Support.

PureNordic

Digestive Support – 120 capsules

A comprehensive formula with digestive enzymes, betaine HCl, ox bile, herbal ingredients and Saccharomyces boulardii. Developed in Norway, with no artificial additives.

499 kr View product

Wondering how long you should take a digestive supplement? We’ve written in detail about it in How long should I take Digestive Support?

The PureNordic approach: inside and out

We see skin health as something built from three directions at once: what you eat and digest, cellular energy and fatty acid balance, and what you do to the skin itself. None of these replaces the others.

Are you also experiencing more hair loss than usual?

Some people dealing with skin and digestive problems also notice more hair loss than before. This is not the same as eczema and shouldn’t be confused with it – but in some cases, both may be affected by similar underlying factors, such as nutritional status and low-grade inflammation. We take a closer look at hair loss and gut health in a separate article.

What should you do now?