AKT · Dermatology/Inflammatory & papulosquamous

Atopic dermatitis/eczema

Skin-barrier (filaggrin) dysfunction + Th2 inflammation

Overview

A chronic, relapsing, intensely itchy inflammatory skin disease driven by skin-barrier (filaggrin) dysfunction and Th2 inflammation, part of the atopic march (asthma, allergic rhinitis). Itch is the cardinal symptom; the distribution is FLEXURAL in children — the mirror image of psoriasis.

Recognise

Itch is the defining symptom; dry skin (xerosis), ill-defined erythema, excoriation
Flexural distribution in children (antecubital and popliteal fossae); face and extensors in infants
Chronic scratching → lichenification (thickened, leathery skin with accentuated markings); personal/family history of atopy

Red flags

Eczema herpeticum — monomorphic punched-out painful erosions, unwell/febrile (HSV superinfection): same-day, oral/IV aciclovir
Bacterial infection — weeping with golden/honey crust (Staphylococcus aureus)

Differentials & how to tell them apart

Contact dermatitiseczema confined to the site of contact/exposure (e.g. under jewellery, occupational on hands)

Psoriasiswell-demarcated, extensor, silvery scale — eczema is ill-defined and flexural

Scabiesburrows in finger web-spaces, severe nocturnal itch, affected household contacts

Tineaannular with an active scaly edge, KOH positive, asymmetrical

Seborrhoeic dermatitisgreasy scale, scalp/nasolabial, in infants = cradle cap

Clinical image

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Atopic dermatitis/eczema — clinical imagesDermNet

Investigations

Clinical diagnosis. Bacterial/viral swab if infection suspected. Consider allergy assessment only if a specific consistent trigger is suspected.

Management

Liberal emollients + a topical corticosteroid of potency matched to severity for flares

1Complete emollient therapy (frequent emollient + soap substitute) PLUS a topical corticosteroid of appropriate potency during flares.Gate: Match steroid potency to severity AND site — use a mild steroid (e.g. hydrocortisone) on the face and flexures, reserve potent steroids for thick/lichenified limb or trunk skin; for ongoing facial disease use a calcineurin inhibitor instead
2Infected eczema (weeping, crusted) → oral flucloxacillin. Suspected eczema herpeticum (monomorphic punched-out erosions, unwell) → same-day oral/IV aciclovir.
3Not controlled by optimal topical therapy → dermatology: phototherapy, systemic immunosuppression, or dupilumab.

Emollients — the mainstay — applied liberally and frequently, including a soap substitute

Topical corticosteroids — potency matched to severity and site, used in flares (mild on face/flexures → potent on lichenified limbs)

Topical calcineurin inhibitors (tacrolimus, pimecrolimus) — steroid-sparing for face and flexures / longer-term control

Flucloxacillin; aciclovir — flucloxacillin for bacterial infection; aciclovir for eczema herpeticum

Phototherapy; ciclosporin, methotrexate, dupilumab — severe disease, under dermatology

Key points

Eczema herpeticum is the emergency not to miss. Avoid potent steroids on the face. In children on potent steroids, monitor growth. Bandages/wet wraps can help severe localised disease.

Monitor & prognosis

Disease control, infection, and (children on potent steroids) growth.

Many children improve markedly by adolescence; can persist or relapse into adulthood.

Source: NICE CKS Eczema - atopic; NICE CG57