Eczema is a term used for a group of inflammatory skin disorders characterised by itching, inflammation, and disruption of the skin barrier. In everyday British medical usage, "eczema" commonly refers particularly to atopic eczema, although other forms include contact eczema, discoid eczema, and other clinically distinct patterns. Atopic eczema often begins in childhood but can persist into adulthood or begin later. The skin can become dry, itchy, inflamed, cracked, thickened, or weeping depending on the stage and severity.
Eczema is not simply dry skin: impaired barrier function, immune dysregulation, genetic factors, environmental triggers, and interactions with skin microorganisms all contribute. The disease can fluctuate between flares and periods of relative control, and its appearance varies according to age, skin tone, anatomical site, and disease stage.
Atopic eczema involves abnormalities of the epidermal barrier and immune regulation. Filaggrin is an important protein involved in epidermal structure and barrier function, and loss-of-function variants in the FLG gene can increase susceptibility to atopic eczema, although many affected people do not carry such variants and genetic susceptibility is multifactorial. Barrier disruption increases transepidermal water loss and can facilitate penetration of irritants and allergens. Type 2 immune pathways involving cytokines such as interleukin-4 and interleukin-13 are important in many cases. The relationship between barrier dysfunction and inflammation is bidirectional: inflammation can further impair barrier integrity, while barrier disruption can promote inflammatory responses. This creates a cycle of dryness, itching, scratching, and further skin injury.
Common triggers include soaps, detergents, fragrances, sweating, heat, dry environments, rough fabrics, stress, infections, and individual allergens or irritants. Not every trigger causes disease in every person, and trigger avoidance should be based on the individual's pattern rather than assuming that one universal list applies. Scratching can cause mechanical damage, increase inflammation, and introduce microorganisms into broken skin. This is sometimes described as the itch-scratch cycle.
The distribution of eczema changes with age: infants often have involvement of the face and extensor surfaces, while older children and adults commonly develop eczema in flexural areas, although patterns vary. Skin colour also affects visual assessment because redness may be less obvious in darker skin, where inflammation can appear brown, purple, grey, or darker than surrounding skin.
Secondary infection is an important complication of Eczema because impaired barrier function can facilitate microbial colonisation and invasion. Staphylococcus aureus commonly colonises affected skin and can contribute to inflammatory flares in some people. Viral infections such as eczema herpeticum can be serious and require prompt medical assessment. Signs suggesting significant infection can include rapidly worsening inflammation, pain, oozing, crusting, blistering, fever, or systemic illness, although individual findings vary. Not every moist or crusted eczema lesion is necessarily infected, and unnecessary antimicrobial treatment can create adverse effects and resistance. Correct assessment distinguishes ordinary eczema inflammation from bacterial, viral, or other infection requiring specific treatment.
Diagnosis of Eczema is usually clinical because there is no single laboratory test that establishes atopic eczema. Assessment considers the pattern and distribution of lesions, itching, chronicity, personal or family history of atopy, skin dryness, triggers, and response to treatment. Patch testing can be useful when allergic contact dermatitis is suspected, particularly in adults with persistent or atypical disease. Allergy testing may identify sensitisation but does not automatically establish that a particular allergen is responsible for eczema. Skin biopsy is occasionally used when the diagnosis is uncertain or another inflammatory skin disease must be excluded. Accurate diagnosis is particularly important because psoriasis, fungal infections, contact dermatitis, scabies, and several other disorders can resemble eczema.
Management focuses on restoring the skin barrier, reducing inflammation, controlling itch, and preventing flares. Regular emollient use helps reduce water loss and improve barrier function, while topical corticosteroids are commonly used to suppress inflammatory flares. Other topical anti-inflammatory medicines can be appropriate in particular circumstances or anatomical sites. Severe or refractory disease may require phototherapy or systemic treatments, including targeted biological medicines or other immunomodulatory drugs.
Treatment potency and duration should be appropriate to the body site and severity because thin skin areas are more susceptible to certain treatment complications. Consistent maintenance treatment can reduce the frequency and severity of flares, while intermittent anti-inflammatory treatment may be used proactively in areas that repeatedly relapse under appropriate clinical guidance.
Eczema has important effects beyond visible skin inflammation. Persistent itching can disturb sleep, while pain, visible lesions, scratching, and treatment requirements can affect concentration, school attendance, work, social interaction, and psychological wellbeing. Severe disease can require substantial daily management and can impose burdens on families caring for affected children. Eczema is associated with other atopic conditions, including allergic rhinitis, food allergy, and asthma, although the presence of eczema does not mean that a person necessarily has all of these conditions. Food allergy can be relevant in selected patients, particularly infants with immediate reactions to specific foods, but indiscriminate dietary elimination is not an appropriate treatment for eczema and can create nutritional problems.
Eczema differs from psoriasis even though both can cause chronic inflamed and scaly skin. Atopic eczema commonly produces intense itch and often affects flexural areas, whereas psoriasis typically produces more sharply demarcated plaques with characteristic scaling, often on extensor surfaces, although both diseases have considerable variation. Eczema is also distinct from contact dermatitis, although contact allergens or irritants can contribute to or mimic atopic eczema. A common misconception is that eczema is caused by poor hygiene; excessive washing and harsh cleansers can actually worsen barrier disruption. Another misconception is that topical corticosteroids inevitably damage skin when used appropriately; their safety depends on potency, site, frequency, duration, and correct medical use.
