Atopic dermatitis !
Atopic dermatitis (eczema) is a long-lasting, itchy skin inflammation that usually begins in childhood and comes and goes in flares.
Updated 2026-11-01
Structures involved
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In the clinical exam
Why it happens
- Innate and adaptive immunity: overview
- Skin: epidermis layers, dermis, hypodermis
- Keratinocytes, melanocytes, Langerhans and Merkel cells
What it is
A chronic, relapsing, inflammatory skin disease with intense itch, dry skin and eczematous lesions in typical locations for each age. It is the most common form of eczema and often appears with asthma and allergic rhinitis.
Who gets it
One of the most common chronic skin diseases of childhood worldwide, usually starting before age 5 and often in the first year. Studies in Latin American cities show a high prevalence of eczema symptoms in children. Many children improve with age, but it can persist into adulthood.
Causes
- Defective skin barrier, often from filaggrin gene mutations
- Type 2 (Th2) immune inflammation with IL-4 and IL-13
- Environmental triggers acting on a genetic background
Risk factors
- Family history of eczema, asthma or allergic rhinitis
- Personal history of other atopic diseases
- Urban living and dry or cold climates
- Irritants: harsh soaps, wool, sweat
- Allergens such as house-dust mite; food allergy in some infants
Pathophysiology
A leaky epidermal barrier loses water and lets irritants and allergens in, which activates type 2 inflammation and IgE sensitisation. Inflammation and scratching damage the barrier further (itch-scratch cycle), and colonisation by Staphylococcus aureus worsens flares. Early-onset eczema is often the first step of the atopic march toward food allergy, asthma and allergic rhinitis.
Classification
- Infantile: face, scalp and extensor surfaces, sparing the nappy area
- Childhood: flexural folds (antecubital and popliteal fossae), wrists, ankles and neck
- Adolescent and adult: flexures, hands, face and neck, with lichenified plaques
- Severity: mild, moderate or severe (e.g. by SCORAD or EASI scores)
Symptoms and signs
- Intense itching, often worse at night and disturbing sleep
- Dry skin (xerosis)
- Red, scaly, sometimes oozing and crusted patches in age-typical locations
- Thickened, leathery skin with marked lines (lichenification) from chronic scratching
- Associated signs: Dennie-Morgan infraorbital folds, palmar hyperlinearity, keratosis pilaris
Diagnosis
- Clinical
- Clinical diagnosis based on itch, typical morphology and distribution for age, chronic relapsing course and personal or family history of atopy (e.g. Hanifin-Rajka or UK Working Party criteria).
- Tests
- Usually not needed. Total IgE and eosinophils may be raised; specific allergy testing only when a food or contact allergy is suspected; skin swab or viral PCR when infection is suspected.
- Imaging
- Not needed.
Differential diagnosis
- Seborrhoeic dermatitis (infants: scalp and nappy area)
- Allergic or irritant contact dermatitis
- Scabies
- Psoriasis
- Tinea (fungal infection)
- Cutaneous T-cell lymphoma in adults with new widespread eczema
Goal of treatment
Restore the skin barrier, control inflammation and itch, prevent flares and infection, and improve sleep and quality of life.
Treatment
- Conservative
- Daily emollients and gentle cleansing are the foundation; avoiding irritants and known triggers; keeping nails short.
- Medical
- Topical corticosteroids of appropriate potency for flares, and topical calcineurin inhibitors (tacrolimus, pimecrolimus) for the face and folds or as maintenance.
- Procedure
- Narrowband UVB phototherapy for moderate to severe disease not controlled topically.
- Medical
- Systemic therapy for severe disease: biologics targeting IL-4/IL-13 (e.g. dupilumab), JAK inhibitors, or immunosuppressants such as cyclosporine or methotrexate; oral antibiotics or antivirals for infection.
- Follow-up
- Education of patients and caregivers on skin care, flare action plans and signs of infection; growth and sleep in children.
Complications
- Secondary bacterial infection (Staphylococcus aureus impetiginisation)
- Eczema herpeticum (herpes simplex infection)
- Sleep disturbance, anxiety and reduced quality of life
- Adverse effects of long-term potent topical corticosteroids (skin atrophy)
- Atopic march: food allergy, asthma and allergic rhinitis
Prognosis
Many children improve or clear by adolescence, but the tendency to dry, sensitive skin often persists and some have lifelong disease. Early onset and severe disease predict persistence.
Prevention
- Regular emollient use and avoidance of irritants to reduce flares
- Early recognition and treatment of skin infection
Test yourself
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Where are atopic dermatitis lesions typically found in older children?
In the flexural folds, such as the antecubital and popliteal fossae, plus wrists, ankles and neck.
What is the atopic march?
The typical sequence in which early eczema is followed by food allergy, asthma and allergic rhinitis.
Which skin-barrier protein is commonly affected by mutations in atopic dermatitis?
Filaggrin.
Which complication of atopic dermatitis is a dermatological emergency?
Eczema herpeticum: widespread herpes simplex infection with painful punched-out erosions, often with fever.
What is the foundation of atopic dermatitis management?
Daily emollients to restore the skin barrier and avoidance of irritants, with topical corticosteroids for flares.
Related conditions
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Atopic dermatitis (MedlinePlus, US National Library of Medicine, 2026); Atopic Dermatitis (National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), 2026).
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Representative model, for educational purposes only.
