Eczema is often spoken about as though it has one cause — but it's really the result of several things overlapping: your genes, your skin barrier, your immune system and your environment. Understanding how those pieces fit together (and which type of eczema you have) is the first step to managing it well.
Eczema is caused by a combination of factors: a genetic tendency (often involving the filaggrin gene), a weakened skin barrier that lets moisture out and irritants in, an overactive immune response, and environmental triggers. There are several types — atopic, contact, nummular and dyshidrotic — each with its own triggers. Eczema is not contagious, and while diet plays a minor, unproven role at most, it's not simply caused by a zinc deficiency.
Eczema doesn't have one cause — it comes from four things interacting. A genetic tendency (often changes in the filaggrin gene and other barrier/immune genes), a leaky skin barrier (which lets water escape and irritants and allergens in), an overactive immune response, and environmental triggers. These combine differently across the main types: atopic (genetic, barrier-related, often part of the "atopic march" with asthma and hay fever), contact (allergic or irritant), nummular (coin-shaped patches) and dyshidrotic (itchy blisters on hands and feet). Eczema is not contagious, and it isn't simply caused by a zinc deficiency — that link is limited and unproven. See a doctor to identify your type and triggers.
What Is Eczema?
"Eczema" is an umbrella term for a group of chronic inflammatory skin conditions — the most common being atopic dermatitis. It typically shows up as itchy, dry, red or inflamed skin that comes and goes in flares, and repeated scratching can lead to lichenification (skin that becomes thickened and leathery). It can affect any age but is especially common in infants and young children.
An important myth to clear up: eczema is not contagious. It's also not dangerous in the medical sense — but that undersells it, because the itch, discomfort and appearance can genuinely affect sleep, confidence and quality of life.
What Actually Causes Eczema?
Rather than one trigger, eczema arises when several factors line up:
- Genetics. Eczema — especially atopic — runs in families. Changes in the filaggrin gene (which helps build a healthy barrier), along with other barrier and immune genes, make skin more prone to it.
- A weakened skin barrier. With less filaggrin and fewer barrier lipids (like ceramides), the skin can't hold water in or keep irritants and allergens out — so it dries, cracks and reacts more easily.
- An overactive immune response. The immune system over-reacts (a Th2-type inflammation), amplifying redness and itch.
- Environmental triggers. Irritants, allergens, weather, sweat and stress can all tip sensitive skin into a flare.
In atopic eczema, this tendency is often part of the "atopic march" — the clustering of eczema with asthma, hay fever and food allergies. (You may also see the hygiene hypothesis raised — the idea that less early-life exposure to microbes nudges the immune system toward allergy. It's a plausible but still-debated explanation, not settled fact.)
The Main Types (And Their Triggers)
Because the different types have different triggers, identifying which one you have really matters for management:
- Atopic eczema (atopic dermatitis) — the most common; genetic, barrier- and immune-related, flaring over time. Often improves through childhood, though it can persist or begin in adulthood.
- Contact eczema — triggered by something the skin touches. Allergic contact eczema is an immune reaction that only develops in people who've become sensitised to a specific allergen; irritant contact dermatitis is direct damage from a harsh substance and can affect almost anyone. It settles once the trigger is removed.
- Nummular (discoid) eczema — well-defined, coin-shaped patches, often on the limbs. Causes are multifactorial; risk factors include dry skin, harsh irritants, and sometimes tobacco or alcohol.
- Dyshidrotic eczema (pompholyx) — tiny, intensely itchy blisters on the palms, soles and sides of the fingers/toes. Often linked to allergies, stress, prolonged water contact, and metals like nickel or cobalt.
What About Zinc And Diet?
You may have read that eczema is caused by a zinc deficiency. The evidence here is limited and inconclusive: some studies have found lower zinc levels in people with atopic dermatitis, but it's unclear whether low zinc is a cause or a consequence, and the studies are small. There's no established "deficiency eczema" as a distinct type.
Crucially, zinc supplementation is not an established eczema treatment. It's only reasonable if a doctor confirms a genuine deficiency through testing — so please don't self-supplement (too much zinc has its own downsides). The same goes for diet more broadly: it may play a small, uncertain role, but eczema is driven mainly by your barrier, immune system and genetics, not by food alone.
A Note On Deeper Skin Tones
Eczema can look quite different on medium-to-deep skin — and this genuinely matters, because it's often under-recognised. The classic "redness" may appear more grey, violet, or darker brown rather than bright red, so inflammation can be missed or underestimated. Eczema on deeper skin also more often shows up as small bumps around hair follicles (a follicular pattern), and once a flare settles it can leave lasting dark or light marks (post-inflammatory pigment change). The takeaways: don't rely on "redness" alone to judge a flare, and treat gently and early — calming inflammation quickly is the best way to limit those marks.
What This Means For You
Knowing that eczema has several overlapping causes — and several types — takes some of the mystery (and self-blame) out of it. It's not something you "caught" or brought on yourself; it's how sensitive, barrier-challenged skin responds to the world. The encouraging part is that it's very manageable: supporting the skin barrier, identifying and avoiding your triggers, and using the right medical treatment can keep flares under control. A doctor or dermatologist can confirm which type you have and build a plan around it. To go further, see whether eczema can go away, how it differs from psoriasis, and gentle skin-care considerations for eczema-prone skin.
- Not one cause — genetics + barrier + immune system + triggers.
- Filaggrin & barrier — central to atopic eczema; often runs in families.
- Several types — atopic, contact, nummular, dyshidrotic — different triggers.
- Not contagious — and not simply caused by a zinc deficiency.
- Looks different on deeper skin — grey/violet/darker, not always red.
Eczema is caused by several factors working together: a genetic tendency (often the filaggrin gene), a weakened skin barrier, an overactive immune response, and environmental triggers. It comes in different types — atopic, contact, nummular and dyshidrotic — each with its own triggers. It's not contagious, and it isn't simply down to a zinc deficiency or diet. On deeper skin it can look grey or violet rather than red, so it's easy to under-treat. Identifying your type and triggers with a doctor is the key to managing it well.
The most useful reframe here is that eczema is a barrier story as much as an immune one — which is why gentle, barrier-supportive care is such a cornerstone of living with it. We'd also gently push back on the "just take zinc" or "it's your diet" narratives: the evidence is thin, and self-supplementing isn't the answer. And because eczema so often reads differently on deeper skin, we think that under-recognition deserves far more attention than it usually gets.
Frequently Asked Questions
What causes eczema?
Eczema doesn't have a single cause — it comes from a combination of factors: a genetic tendency (often involving the filaggrin gene and other barrier/immune genes), a weakened skin barrier that lets water out and irritants and allergens in, an overactive immune response, and environmental triggers. These interact differently across the various types of eczema, which is why the condition looks and behaves differently from person to person.
Is eczema genetic?
Genetics play a major role, especially in atopic eczema, which often runs in families. Changes in the filaggrin gene (which helps build a healthy skin barrier) and other barrier and immune genes make skin more prone to eczema. It's frequently part of the "atopic march", alongside asthma, hay fever and food allergies. But genes aren't the whole story — a weakened barrier and environmental triggers matter too.
What are the main types of eczema?
The common types include atopic eczema (the most frequent, genetic and barrier-related), contact eczema (allergic — an immune reaction to an allergen; or irritant — direct damage from a substance), nummular or discoid eczema (coin-shaped patches), and dyshidrotic eczema or pompholyx (tiny itchy blisters on the hands and feet). Each has different triggers, so identifying the type helps guide management.
Does zinc deficiency cause eczema?
The evidence is limited and inconclusive. Some studies have found lower zinc levels in people with atopic dermatitis, but it isn't clear whether low zinc is a cause or a consequence, and zinc supplementation is not an established eczema treatment. It's only worth considering if a doctor confirms a genuine deficiency — you shouldn't self-supplement. Eczema is mainly driven by genetics, the skin barrier and the immune system, not by diet alone.
Is eczema contagious?
No — eczema is not contagious. You can't catch it from or pass it to someone else through contact, because it's driven by a person's own genetics, skin barrier and immune response rather than by an infection. (Broken eczema skin can occasionally develop a secondary infection, and infections themselves can be contagious, but the eczema itself is not.)
Boldpurity Science Team
Boldpurity is a clinical skincare brand with in-house cGMP manufacturing in Hyderabad, India, formulating evidence-led skincare for medium-to-deep skin tones. Content is prepared and science-reviewed by the Boldpurity Science Team.
Editorial Process
Articles are drafted from peer-reviewed dermatology literature and authoritative clinical sources, science-reviewed for accuracy, and kept at an education level. We report the strength of evidence honestly (for example, on zinc and diet), add deeper-skin context often missing elsewhere, make no product claims, and route diagnosis to professionals.
Reference Policy
Claims are supported by cited sources (see References), including dermatology guidance on the causes and types of eczema. Where evidence is limited (such as zinc supplementation), we say so.
Medical Disclaimer
This article is general information, not medical advice, and does not diagnose or treat any condition. Do not start supplements such as zinc without medical guidance. Consult a doctor or dermatologist to identify your type of eczema, its triggers, and the right management for you.
This article is educational, does not diagnose or treat any condition, and does not recommend specific products or supplements. The link between zinc (or diet) and eczema is limited and unproven; do not self-supplement — seek medical advice. Consult a doctor or dermatologist for diagnosis and management of eczema.
- American Academy of Dermatology (AAD). Atopic dermatitis: causes. aad.org.
- National Eczema Association. What causes eczema? nationaleczema.org.
- DermNet. Atopic, contact, discoid (nummular) and dyshidrotic eczema. dermnetnz.org.
- Orchard D. Eczema management in school-aged children. Aust Fam Physician. 2017.
