Atopic dermatitis (atopic eczema)

Synonyms: Neurodermitis

By Dr. Pascal Bafteh · last updated 09/2026

Definition

Chronic-recurrent, non-contagious inflammatory dermatosis due to barrier defect and dysregulation of the innate and adaptive immune system with Th2 dominance.

Atopy & Atopic March

Hypersensitivity to physical and chemical stimuli as well as IgE-mediated allergens; part of the atopic triad (Atopic dermatitis, Bronchial asthma, allergic rhinoconjunctivitis). Atopic March: Infantile eczema → later Asthma or Rhinitis.

Prevalence & Risk

Children 15–20 %, Adults 1.5–5 %. No parent affected: 15 %; both parents affected: 60–80 %.

Genetics / Barrier

Filaggrin mutation → ↓ NMF (Natural Moisturizing Factor), ↑ pH of the skin surface, ↑ TEWL (Transepidermal Water Loss). Additionally ↓ Claudin-1/3, ↓ Ceramides, SPINK5 mutation, changes in IL-4, IL-13, IL-4R and FcεRI → barrier defect and allergen penetration.

Diagnostic Criteria (Hanifin-Rajka 1980, modified according to DDG 2024)

Major Criteria (≥ 3 of 4 required)

• Major triad is chronic-recurrent with pruritus + history of atopy and age-dependent localization.

Minor Criteria / Atopic Stigmata (≥ 3 additional for diagnostic confirmation)

• Stigmata are facial pallor + palmar hyperlinearity with pulpitis sicca + nipple eczema and ear rhagades + pityriasis alba.
• Further classic stigmata:
• Dirty Neck (livid-brownish discoloration on neck/décolleté)
• Keratoconus (cone-shaped corneal deformation)
• Fur cap-like hairline (especially fronto-temporal)
• Cradle cap (infants — yellowish-crusted plaques on cheek/forehead)
• Keratosis follicularis (chicken skin) on extensor surfaces of upper arms/thighs
• Angular cheilitis (cheilitis sicca)
• Xerosis cutis (generalized dryness)
• Periorbital darkening ("Haloed eyes")
• Dennie-Morgan fold with double lower eyelid fold.
• White dermographism (skin streak turns white instead of red, in contrast to urticaria)
• Hertoghe's sign with thinned lateral eyebrows.

Common Provoking Factors (Trigger Factors)

• Allergic: House dust mites, animal dander, pollen, food allergens (cow's milk, chicken egg, soy, wheat, peanut in children; nuts, fish in adults).
• Irritant: Wool, sweating, surfactants / soaps, dry heated air, swimming pool chlorine.
• Microbial: Staphylococcus aureus (superantigen), Pityrosporum (head-neck form), HSV (Eczema herpeticatum).
• Stress, Hormonal fluctuations, Sleep deprivation.

Clinical Presentation by Age Phase

• Terminology: the pattern of childhood and adolescence is called eczema flexurarum (flexural eczema); in infancy one speaks of eczema infantum with crusta lactea (cradle cap), and in adulthood eyelid, hand and head-and-neck involvement is added.

Severity Scores (DDG-S3 Guideline)

• EASI (Eczema Area and Severity Index) — Quantification of erythema + infiltration + excoriation + lichenification × area.
• SCORAD (Scoring Atopic Dermatitis) — combines area + clinical signs + subjective symptoms.
• DLQI (Dermatology Life Quality Index) — Patient-Reported Outcome (10 questions).
• POEM (Patient-Oriented Eczema Measure) — Symptom score over 7 days.

Complications

• Eczema herpeticatum (HSV infection) — extensive umbilicated vesicles, emergency.
• Eczema molluscatum (HPV molluscum dissemination).
• Bacterial superinfection (S. aureus, "honey-colored crusts").
• Erythroderma in generalized course.
• Ocular involvement: Keratoconus, cataract (cup-shaped), conjunctivitis.

Differential diagnoses

• Allergic contact dermatitis
• Psoriasis vulgaris (plaque psoriasis)
• Seborrhoeic dermatitis
• Urticaria
• Mycosis fungoides
• Dyshidrotic hand eczema (pompholyx)
• Scabies
• Nummular eczema

Sources (selection)

1. AWMF S3 Neurodermitis 2023
2. Huang et al. 2022

More allergies and eczemas

• Angioedema
• Mastocytosis (urticaria pigmentosa)
• Seborrhoeic dermatitis
• Urticaria

Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.