Dysbiosis, permeability, and the gut–skin axis. Below: the plausible mechanism in plain language, then the
literature graded honestly — the strongest evidence here is
Grade B — and the functional tests
worth raising with a clinician.
The mechanistic link
Read through the functional lens, eczema is treated as a possible
downstream signal rather than the whole story. The
Gut / Microbiome system enters the picture because dysbiosis, permeability, and the gut–skin axis. Each link below is a hypothesis to discuss, never a
diagnosis or a cure claim, and every page clears a human review gate
before it is published.
The evidence
What the literature actually supports.
Each statement carries an A–D strength badge and resolvable
citations. Grades describe how strong the underlying research is —
never whether something is good or bad for you.
How to read the grades →
Infants and children with atopic eczema tend to show lower gut-microbial diversity and a different early colonisation pattern than unaffected peers, consistent with a gut–skin axis contribution rather than a purely skin-local process.
“Reduced early-life gut microbial diversity preceded the onset of atopic dermatitis in this prospective cohort.”
Increased intestinal permeability has been observed in a subset of people with eczema, offering a plausible route by which gut-derived signals could amplify systemic and cutaneous inflammation — mechanistic and not yet causal.
Citations are stable corpus references; resolvable outbound links land
with the literature pipeline (Epic C). These entries are fixtures
until Epic D generates reviewed content.
IFM Matrix anchor
Assimilation
Assimilation covers how the body breaks down, absorbs, and tolerates what enters the gut — digestion, the microbiome, and barrier integrity. It is the IFM node where the gut–skin axis is described.
Each system maps to a node on the IFM Functional Medicine Matrix; the
full mapping and its limitations live on the
methodology page →
Tests for this system
What you could actually ask to measure.
Functional and conventional tests that probe the gut / microbiome
link for eczema. Findings are cited and graded; some require
more than one biomarker read together.
Intestinal permeability panel
Functional / specialist
Gut barrier integrity and low-grade intestinal inflammation, via serum and stool markers, to gauge whether a 'leaky' barrier could be feeding the gut–skin axis.
Elevated serum zonulin has been associated with greater intestinal permeability and, in some atopic-dermatitis cohorts, with disease severity — supportive, not diagnostic.
Zonulin elevated together with raised faecal calprotectin points to a barrier defect alongside active mucosal inflammation — a multi-biomarker pattern that is more informative than either marker alone for prioritising a gut-directed conversation in eczema.
Combination · Zonulin + Faecal calprotectin
Grade D: Early — hypothesis / expert opinionfixture-permeability-inflammation-combo-2021
Take it to your appointment
The Gut / Microbiome test checklist for eczema.
A free, citation-backed one-pager of the gut / microbiome
tests above — what each measures and the findings to discuss
— so the conversation with your clinician starts informed.