Part of our complete guide to eczema and dermatitis in the UK.
What Is Eczema? Types, Causes & Symptoms UK
A clinically reviewed guide to eczema — what it is, the six types, the biology behind why it happens, common triggers, the itch-scratch cycle, diagnosis and the NICE treatment ladder.
▶ What is eczema?
Eczema is a chronic inflammatory skin condition causing dry, itchy, inflamed skin. The most common type is atopic eczema, affecting 1 in 5 children and 1 in 12 adults in the UK. It is caused by a combination of a filaggrin gene barrier defect and Th2 immune dysregulation. Not contagious. Not caused by poor hygiene.
Eczema is one of the most common skin conditions in the UK — and one of the most frequently misunderstood. People are told to moisturise more, avoid baths, cut out dairy, or just wait for it to improve. Some of that advice is partially right; most of it misses the underlying biology. This guide explains what eczema actually is, why it happens, how different types differ from each other, and how it is managed in line with current NICE guidance.
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View Eczema Treatments →What Is Eczema?
Eczema is a chronic inflammatory skin condition characterised by dry, itchy, and inflamed skin. The word comes from the Greek for “to boil over” — which captures the hot, weeping quality of a severe flare. The most common form is atopic eczema (atopic dermatitis), but the term covers a family of related inflammatory skin conditions.
Eczema is not contagious. It is not caused by poor hygiene. It is not simply dry skin that needs more moisturiser. It is a systemic inflammatory condition that expresses itself in the skin — driven by genetics, immune dysregulation, and a disrupted skin barrier. Understanding this is important because it explains why basic moisturisers alone rarely control it during a flare, and why targeted anti-inflammatory treatment is usually required.
1 in 5
Children in the UK affected by atopic eczema (NHS)
1 in 12
Adults in the UK affected
6
Recognised types of eczema and dermatitis
~50%
Of children see significant improvement by adulthood
The Six Types of Eczema
| Type | Key features | Common sites | Primary cause |
|---|---|---|---|
| Atopic eczema | Chronic, relapsing; linked to asthma and hay fever; typically begins in childhood | Flexures (elbows, knees), face, hands, scalp | Filaggrin gene mutations; Th2 immune dysregulation |
| Contact dermatitis | Irritant (repeated exposure) or allergic (immune sensitisation) | Hands, wherever contact occurs | Soaps, detergents, nickel, fragrances, latex |
| Discoid eczema | Well-defined coin-shaped inflammatory patches; tends to affect adults | Limbs — lower legs and forearms | Poorly understood; skin injury; dry skin |
| Seborrhoeic dermatitis | Flaking, redness in sebaceous areas; linked to Malassezia yeast | Scalp, face (nasolabial folds, eyebrows), chest | Malassezia overgrowth; stress; immunosuppression |
| Dyshidrotic eczema | Small intensely itchy blisters; worsens with heat and stress | Palms, soles, sides of fingers and toes | Sweat; stress; contact allergens; heat |
| Venous eczema | Skin becomes brown, itchy, and thickened; associated with varicose veins | Lower legs, particularly around ankles | Chronic venous insufficiency |
What Causes Eczema? The Biology Explained
Impaired skin barrier (filaggrin)
Filaggrin is a structural protein essential for forming the outer skin layer. Loss-of-function mutations in the FLG gene — found in ~30% of people with atopic eczema — produce a leaky barrier. Irritants and allergens that healthy skin would block can penetrate, triggering immune activation.
Th2 immune dysregulation
Eczema involves a Th2-skewed immune response — the same pathway that drives asthma and allergic rhinitis. Elevated IL-4, IL-13, and IL-31 drive inflammation. IL-31 is directly responsible for the intense itch signal that characterises eczema.
Skin microbiome disruption
Staphylococcus aureus colonises the skin of more than 90% of people during eczema flares (vs ~5% in unaffected skin). S. aureus toxins further damage the barrier and amplify inflammation — creating a cycle that makes flares self-perpetuating without treatment.
Genetics and family history
If one parent has atopic eczema, the child’s risk is approximately 50%. If both parents are affected, the risk rises to ~80%. Eczema, asthma, and hay fever cluster together in families — the “atopic march” — reflecting a shared immune predisposition.
Common Triggers
Triggers provoke flares in people who already have the underlying condition — they do not cause eczema itself:
- Soap and detergents — the most common irritant. Even mild soaps strip the skin barrier. Replace with fragrance-free soap substitutes.
- Sweat — particularly relevant in children; triggers scratching and perpetuates the itch-scratch cycle.
- Synthetic fabrics — nylon, polyester, and wool irritate eczematous skin. Cotton and breathable fabrics are better tolerated.
- Stress — activates the HPA axis and promotes Th2 skewing, directly worsening inflammation.
- Heat and dry air — central heating and cold weather both worsen barrier function.
- Aeroallergens — house dust mite, pet dander, and pollen — particularly relevant where sensitisation is confirmed by testing.
- Secondary skin infections — S. aureus colonisation is both a consequence and a driver of flares. Signs of infection (weeping, crusting, fever) warrant prompt assessment.
The Itch-Scratch Cycle
The defining symptom of eczema is itch — and scratching worsens the very barrier damage that causes the itch. This self-perpetuating cycle is central to understanding eczema:
IL-31 drives the itch signal in atopic eczema. Scratching releases more inflammatory mediators, amplifying IL-31 further. Over time, repeated scratching produces lichenification — visible thickening and leathering of the skin that further impairs the barrier and requires more potent treatment to control. Breaking this cycle with effective anti-inflammatory treatment is why prescription steroids are sometimes necessary even in mild-appearing cases.
How Eczema Is Diagnosed
Eczema is a clinical diagnosis — no blood test confirms it. A prescriber uses the UK Diagnostic Criteria (Williams et al. 1994), requiring an itchy skin condition in the past 12 months plus three or more of:
- Onset before age 2
- History of flexural involvement (inside elbows, behind knees)
- Visible flexural eczema at the time of examination
- History of generally dry skin
- Personal history of asthma or allergic rhinitis (or first-degree relative with atopic condition in a child under 4)
Patch testing is used where contact dermatitis is suspected. Skin prick tests or specific IgE blood tests are used when aeroallergen or food sensitisation may be contributing.
How Eczema Is Treated
NICE and BAD guidance recommends a stepwise approach. The foundation at every step is daily emollient use — not just during flares, but between them too.
| Step | Treatment |
|---|---|
| All steps | Emollients applied liberally at least twice daily to all affected skin |
| Step 1 | Mild steroid — hydrocortisone 1% (Class 1) for mild eczema, face, and children |
| Step 2 | Moderate steroid — clobetasone 0.05% (Eumovate, Class 2) |
| Step 3 | Potent steroid — betamethasone valerate 0.1% (Betnovate, Class 3). See: Betnovate guide |
| Step 4 | Very potent steroid — clobetasol propionate 0.05% (Dermovate, Class 4); short courses only. See: How Dermovate works |
| Step 5 | Specialist referral: phototherapy, systemic immunosuppressants, dupilumab |
For a full explanation of steroid potency classes and how to choose the right strength, see: Steroid cream strengths UK: the complete potency ladder.
For emollient guidance, see: Emollients for eczema: types, how to use and what the evidence shows.
Eczema herpeticum is a serious complication where herpes simplex virus spreads across eczematous skin — presenting as sudden severe worsening with punched-out blisters, fever, and feeling very unwell. This requires urgent same-day medical assessment. Call 111 or attend A&E. Call 999 in an emergency.
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View Eczema Treatments →Frequently Asked Questions
What is eczema?
Eczema is a chronic inflammatory skin condition that causes patches of skin to become dry, itchy, red, and cracked. The most common type is atopic eczema (atopic dermatitis), which affects around 1 in 5 children and 1 in 12 adults in the UK. It is not contagious and is not caused by poor hygiene.
What are the main types of eczema?
The six main types are: atopic eczema (most common, linked to allergy history), contact dermatitis (caused by irritants or allergens), discoid eczema (coin-shaped patches), seborrhoeic dermatitis (affects oily skin areas including the scalp), dyshidrotic eczema (small blisters on hands and feet), and venous eczema (linked to poor circulation in the legs).
What causes atopic eczema?
Atopic eczema is caused by a combination of a genetic skin barrier defect — particularly mutations in the filaggrin (FLG) gene — and an overactive Th2 immune response. This allows irritants and allergens to penetrate the skin and trigger inflammation. It commonly runs in families alongside asthma and hay fever.
Is eczema the same as dermatitis?
The terms are largely interchangeable. 'Dermatitis' means skin inflammation. 'Eczema' is a specific type of dermatitis. In everyday clinical use, 'eczema' usually refers to atopic eczema specifically.
What are common eczema triggers?
Common triggers include soap and detergents, sweat, synthetic fabrics, stress, heat and dry air, house dust mites, pet dander, and secondary Staphylococcus aureus skin infections. Triggers vary between individuals — identifying personal triggers is a key part of long-term management.
Does eczema go away?
In children, eczema often improves significantly with age and around half see substantial improvement or remission by adulthood. In adults, eczema is a chronic condition that tends to fluctuate between flares and periods of remission rather than resolving permanently. Effective management can keep it well controlled.
When should I see a doctor about eczema?
See a prescriber if eczema is significantly affecting your quality of life or sleep, if OTC treatments are not controlling it, if the skin becomes infected (weeping, crusting, fever), or if you develop signs of eczema herpeticum (sudden severe worsening with punched-out blisters — seek urgent same-day assessment).
References
- NICE. Eczema — atopic: CKS. 2024. cks.nice.org.uk
- NICE. Atopic eczema in under 12s (CG57). Updated 2023. nice.org.uk
- Palmer CN et al. Common loss-of-function variants of filaggrin. Nat Genet. 2006;38(4):441–446.
- NHS. Eczema (atopic). nhs.uk/conditions/atopic-eczema
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional. The treatments discussed are prescription-only medicines — a clinical consultation is required before they can be dispensed. In a medical emergency, call 999.