Atopic dermatitis

Atopic dermatitis (AD), often called “eczema,” is a chronic, relapsing, inflammatory skin disease characterized by intense itch, dry skin, and eczematous lesions that vary by age and body site. It arises from a combination of impaired skin-barrier function and immune dysregulation, leading to cycles of itch and scratching that perpetuate inflammation. AD commonly begins in early childhood, but it can persist or first appear in adults. It is distinct from, though frequently coexists with, other allergic conditions such as asthma and allergic rhinitis.

Key features and clinical presentation

Typical findings include xerosis (dryness), erythema, and poorly defined, itchy patches or plaques. Distribution changes with age: in infants it often involves the face and extensor surfaces; in older children and adults it more commonly favors flexural areas such as the antecubital and popliteal fossae. Flares can be triggered by irritants (soaps, detergents, wool), climate extremes, infections, stress, and scratching. Skin of color may show different patterns (for example, more extensor or follicular involvement), which clinicians should recognize to avoid underdiagnosis.

Causes and mechanisms

Multiple pathways drive AD. Genetic barrier defects—classically loss‑of‑function variants in the filaggrin gene—reduce the skin’s ability to retain water and keep out irritants, allergens, and microbes. Barrier injury stimulates keratinocytes to release “alarmins” (TSLP, IL‑25, IL‑33), promoting a type 2–skewed immune response dominated by cytokines such as IL‑4 and IL‑13, which further suppress barrier proteins and lipids. IL‑31 contributes strongly to itch. The skin microbiome is frequently altered, with Staphylococcus aureus colonization and biofilm formation common during flares.

Epidemiology and impact

AD is one of the most prevalent inflammatory skin diseases worldwide and a major cause of outpatient visits. In the United States, millions of children and adults live with AD, and a substantial proportion have moderate to severe disease. Beyond visible skin symptoms, AD can disrupt sleep, impair school and work performance, and increase risks of anxiety and depression. Skin infections are common; a subset of patients can develop eczema herpeticum, a widespread herpes simplex virus infection that requires prompt antiviral therapy.

Diagnosis and differential

Diagnosis is clinical, based on chronic or relapsing itchy dermatitis with age‑specific morphology and distribution plus supportive features such as xerosis and personal or family history of atopy. Several validated tools (e.g., EASI, SCORAD) help gauge severity. Important differentials include contact dermatitis (allergic or irritant), seborrheic dermatitis, psoriasis, scabies, and cutaneous T‑cell lymphoma in refractory cases. In children, guideline-based criteria emphasize itch plus typical features, with attention to phenotypic variation across skin tones.

Management overview

Care centers on repairing the barrier, reducing inflammation, controlling itch, and preventing infection. Foundational steps include daily liberal use of fragrance‑free emollients; gentle cleansing; avoidance of triggers; and patient education on correct medication use. For flares, topical corticosteroids remain first‑line, tailored to body site and potency. Topical calcineurin inhibitors (tacrolimus, pimecrolimus) are steroid‑sparing options, especially for sensitive areas. Nonsteroidal targeted topicals include a PDE‑4 inhibitor (crisaborole) and a topical JAK inhibitor (ruxolitinib), which recently had its U.S. indication expanded to children 2–11 years. Adjuncts such as wet‑wrap therapy and, in selected moderate–severe cases, dilute bleach baths can reduce severity and bacterial burden. For refractory moderate to severe disease, guideline‑endorsed systemic options include biologics that block IL‑4/IL‑13 signaling (e.g., dupilumab; IL‑13 inhibitor tralokinumab) and oral JAK inhibitors (e.g., abrocitinib, upadacitinib) used with careful risk–benefit assessment. Phototherapy is an evidence‑based alternative. Routine use of systemic corticosteroids is discouraged because of rebound flares and adverse effects.

Why it matters

AD’s combination of high prevalence, chronic itch, sleep loss, visible skin changes, and infection risk makes it a condition with outsized personal and public‑health impact. Accurate diagnosis, culturally competent assessment across skin tones, and adherence to contemporary guidelines allow clinicians and patients to choose effective, steroid‑sparing regimens that improve quality of life and reduce complications. Ongoing research—spanning barrier restoration, microbiome modulation, and precision immunomodulation—continues to expand options for individualized, safer long‑term control.

Sources

• American Academy of Dermatology (AAD). Atopic dermatitis clinical guideline hub (overview of topical, systemic, and comorbidity guidance). https://www.aad.org/guidelines/ad (aad.org)

• AAD news release summarizing updated topical therapy recommendations (moisturizers, topical steroids, calcineurin inhibitors, crisaborole, ruxolitinib; wet wraps and bleach baths). https://www.aad.org/news/updated-atopic-dermatitis-guidelines-topical-therapies (aad.org)

• AAD/JAAD guideline: Management of atopic dermatitis in adults with phototherapy and systemic therapies (strong recommendations for dupilumab, tralokinumab, abrocitinib, baricitinib, upadacitinib; conditional for phototherapy and classic immunosuppressants; against systemic corticosteroids). https://pubmed.ncbi.nlm.nih.gov/37943240/ (pubmed.ncbi.nlm.nih.gov)

• AAAAI/ACAAI Joint Task Force 2023 practice parameter (topicals including TCIs, PDE‑4, topical JAK; wet wraps; dilute bleach baths; systemic biologics and JAK inhibitors; phototherapy). https://pubmed.ncbi.nlm.nih.gov/38108679/ (pubmed.ncbi.nlm.nih.gov)

• NICE Guideline CG57: Atopic eczema in under‑12s—diagnosis and management (updated, with diagnostic criteria and emollient/bathing recommendations). https://www.nice.org.uk/Guidance/CG57 (nice.org.uk)

• National Eczema Association. Eczema facts and U.S. prevalence estimates in children and adults. https://nationaleczema.org/research/eczema-facts/ (nationaleczema.org)

• Pathophysiology reviews on barrier dysfunction, filaggrin, and type‑2 inflammation (IL‑4/IL‑13, IL‑31; neuro‑immune itch). https://pubmed.ncbi.nlm.nih.gov/31182684/; https://pubmed.ncbi.nlm.nih.gov/37758055/; https://pubmed.ncbi.nlm.nih.gov/40985984/ (pubmed.ncbi.nlm.nih.gov)

• Staphylococcus aureus in AD: colonization meta‑analysis and microbiome insights. https://pubmed.ncbi.nlm.nih.gov/38371569/ (pubmed.ncbi.nlm.nih.gov)

• Eczema herpeticum overview (recognition and urgency of antiviral treatment). https://www.ncbi.nlm.nih.gov/sites/books/NBK560781/ (ncbi.nlm.nih.gov)

• Regulatory update: U.S. FDA expands pediatric indication of topical JAK inhibitor ruxolitinib cream to ages 2–11 years (2025). https://www.reuters.com/business/healthcare-pharmaceuticals/us-fda-approves-incytes-eczema-treatment-pediatric-patients-2025-09-18/ (reuters.com)

• Disease burden and mental health impact in U.S. adults (Atopic Dermatitis in America study). https://pubmed.ncbi.nlm.nih.gov/30389491/ (pubmed.ncbi.nlm.nih.gov)

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