Does Sugar Worsen Eczema and Psoriasis? What the Evidence Shows
The connection between high sugar intake and inflammatory skin conditions is more specific than "sugar causes inflammation generally." There are identified mechanisms through which excess dietary sugar contributes to the inflammatory pathways driving both eczema and psoriasis — and understanding them makes the practical dietary guidance more compelling than a vague recommendation to "eat less sugar."
That said, sugar is not the primary driver of either condition. Both eczema and psoriasis have genetic and immune underpinnings that diet cannot address alone. The honest framing is that high sugar intake amplifies the inflammatory environment in which both conditions operate — reducing it helps, but it isn't a cure.
Can sugar worsen eczema or psoriasis?
Possibly — high sugar intake may contribute to inflammation, blood sugar spikes, and immune dysregulation that could worsen eczema and psoriasis symptoms in some people. But "possibly" undersells what the evidence actually shows, and the mechanisms involved are more specific and more directly relevant to both conditions than the vague "sugar causes inflammation" framing that dominates most dietary content about skin conditions. The insulin and IGF-1 spike from high-glycaemic eating activates mTORC1 — the same intracellular signalling pathway that drives keratinocyte hyperproliferation in psoriasis and amplifies the Th2 immune response relevant to eczema — through a route that is distinct from, and compounding with, the NF-κB inflammatory pathway that processed foods and alcohol activate. Fructose adds a further dimension specific to psoriasis: its hepatic metabolism pathway contributes to the non-alcoholic fatty liver disease that is two to three times more prevalent in psoriasis patients and that worsens systemic inflammatory burden through the hepatodermal axis covered in the liver psoriasis article in this series. Whether sugar is a significant personal trigger varies between individuals — but the mechanisms through which it could worsen both conditions are specific, documented, and considerably more interesting than the answer "possibly" implies.
How sugar affects inflammation: the specific mechanisms
Advanced glycation end-products (AGEs). When sugar molecules bind to proteins and fats in the body — a process called glycation — they form advanced glycation end-products. AGEs activate RAGE (receptor for advanced glycation end-products), triggering NF-κB signalling — the master inflammatory switch discussed throughout this series in the context of psoriasis, eczema, and acne. AGE formation is directly proportional to circulating glucose levels, making high-sugar diets a direct driver of NF-κB-mediated inflammatory cytokine production.
This is one of the most specific mechanistic connections between sugar and skin inflammation, and it applies to both conditions rather than being eczema or psoriasis-specific.
Insulin and IGF-1 elevation. High-glycaemic foods raise insulin rapidly, which in turn raises IGF-1 (insulin-like growth factor 1). As covered in the hormonal acne diet article, IGF-1 activates mTORC1 — a cellular signalling complex that promotes inflammatory activity and keratinocyte proliferation. In psoriasis specifically, where keratinocyte hyperproliferation drives plaque formation, consistent IGF-1 elevation through high-glycaemic eating contributes directly to one of the condition's core pathological mechanisms.
Gut microbiome disruption. High sugar and ultra-processed food intake consistently reduces gut microbiome diversity — specifically depleting beneficial bacteria including the Faecalibacterium prausnitzii species that is documented to be lower in psoriasis patients, as covered in the probiotics and leaky gut articles in this series. The gut-skin axis means microbiome disruption from high-sugar diets has downstream effects on systemic immune regulation relevant to both conditions.
Oxidative stress. Elevated blood glucose generates reactive oxygen species — free radicals that overwhelm antioxidant defences and contribute to cellular oxidative stress. Oxidative stress amplifies inflammatory responses in skin cells and is elevated in both psoriasis and eczema. This is separate from the AGE mechanism and represents an additional pro-inflammatory pathway.
Why the evidence is stronger for psoriasis than eczema
This is worth addressing directly because the original article correctly identified it but without explanation.
Psoriasis and metabolic syndrome. Psoriasis is strongly associated with metabolic syndrome — insulin resistance, dyslipidaemia, elevated blood pressure, and central obesity. This comorbidity cluster shares pathological mechanisms with high-sugar dietary patterns: both involve elevated inflammatory cytokines, elevated insulin and IGF-1, and oxidative stress. The association between obesity/metabolic syndrome and psoriasis severity is one of the most consistently documented findings in psoriasis research.
In overweight psoriasis patients, the dietary factors that contribute to metabolic dysfunction — including high sugar intake — are directly relevant to psoriasis severity. Multiple studies have found PASI score improvements with weight loss, which broadly involves reduced sugar and glycaemic load alongside reduced calories.
Eczema and sugar. The relationship is less direct. Eczema's primary drivers — filaggrin deficiency, Th2 immune dysregulation, IgE sensitisation — are not specifically amplified by sugar in the way that psoriasis's Th17/mTORC1 pathways are. The gut microbiome disruption from high-sugar diets does influence the gut-skin axis relevant to eczema, and AGE-mediated inflammation is broadly relevant, but eczema is less tied to the metabolic syndrome cluster than psoriasis. Some people with eczema report clear reactivity to high-sugar foods — but this is more likely through the gut microbiome and general inflammatory load mechanisms than through a specific eczema pathway.
Why sugary foods may trigger flare-ups in some people
1. Increased inflammation
High sugar intake can increase inflammatory activity in the body.
2. Blood sugar spikes
Rapid glucose spikes may:
increase stress hormones
worsen inflammatory pathways
3. Gut microbiome changes
Highly processed diets may negatively affect gut bacteria, which can influence immune health.
4. Weight gain and metabolic health
Obesity is strongly linked to:
psoriasis severity
chronic inflammation
The type of sugar matters
Not all sugar has the same impact. This distinction is worth making explicitly:
Added sugar in processed foods — sucrose, high-fructose corn syrup, glucose syrup — produces rapid blood glucose spikes, drives insulin and IGF-1 elevation, and contributes to the metabolic dysfunction associated with psoriasis severity. Ultra-processed snacks, sugary drinks, pastries, confectionery, and breakfast cereals with added sugar are the primary contributors.
Fructose — particularly concentrated fructose from sugary drinks and processed foods — is metabolised primarily in the liver and has specific associations with non-alcoholic fatty liver disease (NAFLD), which as noted in the milk thistle article is significantly more prevalent in psoriasis patients. High fructose intake directly contributes to this hepatic inflammatory burden.
Natural sugars in whole fruit come packaged with fibre, polyphenols, vitamins, and water that substantially change the metabolic impact. Whole fruit has a much lower glycaemic response than equivalent sugar from processed foods, and the polyphenols actively counter some of the inflammatory effects. The fruits with the most evidence for anti-inflammatory benefit in eczema and psoriasis are covered in the fruits article in this series. Restricting whole fruit intake in the belief that "sugar is bad" is both nutritionally unnecessary and counterproductive.
Does cutting out sugar cure eczema or psoriasis?
No.
Reducing sugar may help some people:
feel less inflamed
improve overall health
reduce flare frequency
But neither eczema nor psoriasis is caused solely by sugar.
These conditions are still driven by:
immune dysfunction
genetics
skin barrier issues
environmental triggers
What actually helps: practical dietary changes
The goal isn't elimination of all sugar — which is neither achievable nor necessary. It's reducing the main contributors to sustained high insulin and IGF-1, AGE formation, gut microbiome disruption, and metabolic dysfunction:
Reduce significantly: sugary drinks (the highest-impact single change), ultra-processed snacks and confectionery, pastries and refined bakery products, breakfast cereals with added sugar, and white bread and refined carbohydrates at high frequency.
Replace with: whole grain alternatives, legumes (low glycaemic, high fibre, prebiotic), vegetables as the primary carbohydrate source, oily fish and nuts for healthy fats, and whole fruit for sweetness and polyphenols.
Monitor alcohol separately. As covered in the diet articles across this series, alcohol is one of the most consistently documented psoriasis triggers — and many alcoholic drinks (beer, sweet wine, cocktails) carry significant sugar loads on top of alcohol's direct inflammatory effects.
Should you avoid sugar completely?
Usually not.
For most people:
moderate sugar intake is unlikely to be the sole issue
extreme restriction can become stressful and unsustainable
A balanced, anti-inflammatory diet is generally more realistic and effective than cutting out all sugar.
What sugar reduction realistically achieves
For most people with eczema or psoriasis, meaningfully reducing added sugar and high-glycaemic food intake:
Reduces baseline inflammatory marker levels over 4–8 weeks of consistent change. Supports gut microbiome diversity. In overweight individuals with psoriasis, contributes to the weight reduction that most consistently correlates with PASI improvement. Reduces the mTORC1 and IGF-1 drive on keratinocyte activity relevant to psoriasis. Does not replace medical treatment or address the genetic and immune foundations of either condition.
The most realistic expectation is a modest reduction in flare frequency and severity as part of a consistent anti-inflammatory dietary pattern — not dramatic clearance.
Foods that may be more problematic
Highly processed sugary foods
sweets and candy
fizzy drinks
pastries
ultra-processed snacks
These may contribute more to inflammation than natural sugars.
Sugary drinks
Linked to:
blood sugar spikes
inflammation
metabolic dysfunction
Better alternatives for skin health
Fruit
Provides:
antioxidants
fibre
vitamins
Whole fruit is generally healthier than refined sugar.
Anti-inflammatory foods
Including:
oily fish
vegetables
nuts and seeds
olive oil
These dietary patterns are more strongly linked to skin health improvements
Signs sugar may be affecting your skin
You may notice flare-ups after:
sugary snacks
processed foods
binge eating sugar
Keeping a food diary may help identify personal triggers.
Skin support for eczema & psoriasis-prone skin
The antioxidant defences relevant to counteracting AGE-mediated inflammation — vitamin C, CoQ10, and vitamin E — are addressed through both dietary improvement and targeted supplementation.
Drought's Skin Support Formulaprovides vitamin C, CoQ10, zinc, vitamin D, and 10 other nutrients selected for their roles in skin barrier function and immune regulation — addressing the nutritional dimensions that dietary improvement alone doesn't fully cover. Made in the UK, suitable for vegetarians, designed for consistent long-term daily use.
FAQs: Sugar, eczema & psoriasis
Does sugar worsen psoriasis?
High-glycaemic eating is more specifically linked to psoriasis severity through insulin/IGF-1 elevation, mTORC1 activation, and the metabolic syndrome cluster that is significantly more prevalent in psoriasis patients.
Can sugar trigger eczema?
Not directly — sugar doesn't trigger the IgE-mediated or filaggrin mechanisms of atopic eczema. But high sugar intake contributes to gut microbiome disruption and AGE-mediated inflammation that can worsen eczema's inflammatory environment.
Should I cut out sugar completely?
No — this is unnecessary and counterproductive if it leads to restricting whole fruit. Target added sugar in processed foods and sugary drinks; whole food sources of sugar are not the problem.
Is fruit bad for eczema or psoriasis?
No — whole fruit sugar comes with fibre, polyphenols, and vitamins that substantially change its metabolic impact. Whole fruit has anti-inflammatory properties relevant to both conditions.
How long does it take for reducing sugar to affect skin?
Meaningful reductions in inflammatory markers from dietary changes typically occur over 4–8 weeks of consistent change. Skin improvements follow, though timelines vary.
What is the highest-impact sugar change for psoriasis?
Eliminating sugary drinks — cola, juice drinks, cordials, sweetened coffee — removes the highest glycaemic load with the least dietary sacrifice.
Summary
High sugar intake worsens eczema and psoriasis through specific mechanisms — AGE-mediated NF-κB activation, insulin/IGF-1-driven mTORC1 signalling, gut microbiome disruption, and oxidative stress. The evidence is stronger for psoriasis through its documented association with metabolic syndrome and insulin resistance. Added sugar from processed foods and sugary drinks is the primary target; whole fruit sugar is not a meaningful concern and whole fruit has anti-inflammatory value for this audience. Meaningful reduction in added sugar as part of a consistent anti-inflammatory dietary pattern modestly reduces flare frequency and systemic inflammatory burden — working alongside medical treatment and nutritional support rather than replacing either.
In short:
Excess sugar may increase inflammation
Some people report flare-ups after sugary foods
Evidence is stronger for psoriasis than eczema
Sugar is not the sole cause of skin conditions
While excess sugar may contribute to inflammation and worsen symptoms in some people, it’s rarely the sole cause of skin flare-ups.
The most effective long-term approach supports your skin across multiple pathways—not just diet alone.
Start your skin support journey →
Written by the Drought Skin team — specialists in natural support for psoriasis, eczema and acne
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