Eczema and Dermatitis UK: A Complete Guide to the Condition

A clinically reviewed guide to eczema and dermatitis — what it is, the six types, what causes it, common triggers, the NHS treatment ladder, secondary infections, and when to seek help. NICE and BAD-aligned throughout.

Eczema affects around 1 in 5 children and 1 in 12 adults in the UK, making it one of the most common chronic skin conditions seen in primary care. Despite its prevalence, it is frequently misunderstood — confused with other skin conditions, undertreated, or managed with products that worsen rather than help it. This guide covers the condition itself: what it is, why it happens, how it is diagnosed, and how it is managed in line with NICE guidance. For prescription treatments, see the linked guides below.

What Is Eczema?

Eczema is a chronic inflammatory skin condition characterised by dry, itchy, and inflamed skin. The word “eczema” comes from the Greek for “to boil over” — which captures the hot, weeping, inflamed quality of a severe flare. The most common form is atopic eczema (also called atopic dermatitis), but the term covers a family of related conditions that share the same core feature: an impaired skin barrier combined with immune-mediated inflammation.

Eczema is not contagious. It is not caused by poor hygiene. And it is not simply “dry skin” — it is a systemic inflammatory condition that happens to express itself in the skin, driven by genetics and immune dysregulation. Understanding this distinction matters, because it explains why basic moisturisers alone rarely control it, and why targeted anti-inflammatory treatment is usually needed during flares.

Types of Eczema and Dermatitis

Several distinct conditions fall under the eczema/dermatitis umbrella. Each has a different cause, distribution pattern, and treatment approach:

What Causes Eczema?

Atopic eczema is caused by the interaction of two factors: a genetic skin barrier defect and immune system dysregulation. Neither alone produces eczema — it is the combination that creates the characteristic inflammatory cycle.

Common Triggers

Triggers do not cause eczema — they provoke flares in people who already have the underlying genetic and immune predisposition. Identifying and reducing personal triggers is a core part of long-term eczema management:

• Soap and detergents — the most common irritant trigger. Even “gentle” soaps disrupt the skin barrier. Soap substitutes (emollient washes) should replace soap entirely.
• Sweat — particularly relevant in children; triggers itching and scratching which perpetuates the itch-scratch cycle.
• Synthetic fabrics — nylon, polyester, and wool are common irritants. Cotton and breathable fabrics are better tolerated.
• Stress — psychological stress activates the HPA axis and promotes Th2 immune skewing, directly worsening eczema inflammation.
• Heat and dry air — central heating removes moisture from air and skin; cold weather reduces sebum production. Both worsen barrier function.
• Aeroallergens — house dust mite, pet dander, and pollen. Particularly relevant in adults with sensitisation confirmed by testing.
• Food allergens — in young children, cow’s milk, egg, peanut, wheat, and soy can trigger or worsen eczema. In adults, food allergy as a direct eczema trigger is less common than widely believed.
• Skin infections — Staphylococcus aureus colonisation is both a consequence and a driver of flares. Signs of secondary infection (weeping, honey-coloured crusting, fever) warrant prompt prescriber assessment.

How Eczema Is Diagnosed

Eczema is a clinical diagnosis — there is no blood test or biopsy that confirms it. A prescriber will look for the characteristic pattern of features set out in UK Diagnosis Criteria (the Hanifin and Rajka criteria, as adapted by Williams et al. 1994, widely used in UK primary care):

• Itchy skin condition in the last 12 months (or parental report of scratching or rubbing in a child)
• Plus three or more of: onset before age 2 / history of flexural involvement / visible flexural eczema / history of dry skin / personal history of asthma or allergic rhinitis (or a first-degree relative in children under 4)

Patch testing may be recommended where contact dermatitis is suspected. Skin prick tests or specific IgE blood tests are used when food or aeroallergen sensitisation is suspected as a contributing factor.

The NHS Treatment Ladder for Atopic Eczema

NICE and BAD guidelines recommend a stepwise approach to atopic eczema management, starting with the least potent appropriate treatment and stepping up as needed. The foundation of management at every step is emollient therapy.

Eczema in Darker Skin Tones

Eczema is frequently underdiagnosed and undertreated in people with darker skin (Fitzpatrick types IV–VI). The redness that is a cardinal sign of eczema in lighter skin may appear as purple, brown, or grey in darker skin, and can be missed on a brief clinical assessment. Additional features to look for include:

• Post-inflammatory hyperpigmentation (PIH) — dark patches that persist after inflammation resolves
• Follicular prominence — eczema may present as small papules around hair follicles rather than confluent patches
• Lichenification developing earlier — due to the itch-scratch cycle on more reactive skin

PIH is often more distressing to patients than the eczema itself. Treatment of the underlying inflammation is the most effective approach to PIH in this context.

The Itch-Scratch Cycle

The defining symptom of eczema is itch — and itch produces scratching, which worsens the very skin barrier damage that causes itch. This self-perpetuating cycle is central to understanding why eczema is so difficult to control without targeted treatment.

IL-31 is the primary cytokine responsible for the itch of atopic eczema. Scratching releases more inflammatory mediators, further amplifying IL-31 signalling. In chronic eczema, repeated scratching produces lichenification — a visible thickening and leathering of the skin that further impairs barrier function and increases the amount of topical treatment needed to achieve control.

Secondary Skin Infections

Eczematous skin is highly susceptible to secondary infection due to the damaged barrier and altered microbiome. The most important infections to recognise:

• Staphylococcus aureus — colonises >90% of eczematous skin during flares. Signs of active infection: weeping, honey-coloured crusting, increased warmth and redness, rapid worsening. Treat with topical or oral antibiotics as appropriate.
• Eczema herpeticum — a serious complication caused by the herpes simplex virus spreading across eczematous skin. Presents as a sudden, severe deterioration with punched-out erosions, fever, and malaise. Requires urgent medical assessment and oral or IV aciclovir.
• Molluscum contagiosum — the poxvirus that causes molluscum spreads more readily across eczematous skin. Often self-resolving but can be extensive in severe eczema.

When to See a Doctor

• Eczema significantly affecting quality of life, sleep, or daily activities
• OTC treatments not providing adequate control after 4–8 weeks
• Signs of secondary infection (weeping, crusting, fever, rapidly worsening flare)
• Any suspicion of eczema herpeticum (see above)
• Eczema spreading to new areas or changing in character
• A child with eczema not controlled by mild steroids and emollients
• Adult eczema developing for the first time after age 40 — warrants investigation to exclude other diagnoses

Eczema & Dermatitis Treatment Guides

Clinically reviewed guides covering all aspects of eczema and dermatitis — from understanding the condition to prescription treatment options. Authored by Dr Abdishakur M Ali, GMC no. 7041056.