By Eczema – the term most people use – refers most commonly to atopic dermatitis, the chronic inflammatory skin condition that affects approximately 31 million Americans. It’s the most prevalent immune-mediated skin condition globally, and one of the conditions where the gap between what people understand about it and what’s actually happening biologically is widest.
Eczema is not an allergy, though allergic triggers can worsen it. It’s not caused by dirt or poor hygiene. It’s not contagious. And for most people, it cannot be “cured” in the way an infection is cured – but it can be controlled, often very effectively, with treatments that have advanced dramatically in recent years.
What Atopic Dermatitis Actually Is
Atopic dermatitis is a chronic, relapsing-remitting inflammatory skin condition driven by two interconnected problems: a defective skin barrier and an overactive immune response.
The “atopic” in atopic dermatitis refers to its place in the “atopic triad” – the clustering of atopic dermatitis, allergic rhinitis (hay fever), and asthma in individuals and families. These three conditions share underlying immune dysregulation and frequently co-occur. Approximately 30% of people with atopic dermatitis also have asthma; 35% have allergic rhinitis.
The Skin Barrier Defect
Healthy skin has a tight, brick-and-mortar barrier structure – skin cells (corneocytes) held together by lipid layers (ceramides, fatty acids, cholesterol). This barrier keeps moisture in and irritants, allergens, and microbes out.
In atopic dermatitis, this barrier is structurally defective. The most important identified cause: loss-of-function mutations in the gene encoding filaggrin (FLG) – a protein essential for forming and maintaining the skin barrier. Filaggrin mutations are present in approximately 30-40% of people with atopic dermatitis.
Without an intact barrier:
- Water escapes (transepidermal water loss – TEWL) – producing the chronic dryness characteristic of eczema
- Allergens, irritants, and microbes penetrate the skin more easily
- The immune system is exposed to substances it shouldn’t encounter, triggering sensitization and inflammation
The Immune Dysregulation
Atopic dermatitis involves a characteristic Th2-skewed immune response – an overactivation of type 2 helper T cells that drives production of cytokines including IL-4, IL-13, and IL-31. These cytokines:
- Promote IgE production and allergic sensitization
- Further impair skin barrier function (IL-4 and IL-13 directly reduce filaggrin expression)
- Drive inflammation and itch
- IL-31 specifically activates itch-specific nerve pathways – explaining the intense pruritus of eczema
This bidirectional worsening cycle – barrier defect allows allergen penetration → immune activation → more IL-4/13 → worse barrier function → more allergen penetration – is why atopic dermatitis is so persistent and why treating inflammation alone without addressing the barrier is insufficient.
Itch is not a side effect of eczema. It’s a core disease mechanism – IL-31 and other mediators directly activate itch-specific nerve fibers in the skin. The scratching that follows worsens barrier disruption and inflammation further. This itch-scratch cycle is one of the most important targets in modern eczema treatment.
The Role of Staphylococcus aureus
Staph aureus colonizes the skin of more than 90% of people with atopic dermatitis (vs approximately 20% of healthy individuals). It’s not just a complication – it actively worsens the disease. Staph produces toxins that act as superantigens (bypassing normal immune regulation to trigger massive immune activation), disrupt the skin barrier, and drive Th2 inflammation. Controlling Staph colonization is an important but often overlooked component of eczema management.
Who Gets Atopic Dermatitis and When
Atopic dermatitis typically begins in infancy or early childhood – approximately 60% of cases start in the first year of life, and 85% by age 5. However, adult-onset atopic dermatitis is increasingly recognized, affecting approximately 1 in 4 adult eczema patients.
Risk factors:
- Family history of atopic dermatitis, asthma, or allergic rhinitis (strongest risk factor)
- Filaggrin gene mutations
- Urban living environments (reduced microbial diversity)
- Early antibiotic use (alters gut and skin microbiome)
- Formula rather than breastfeeding (some evidence)
- Low vitamin D levels
The hygiene hypothesis: Reduced early-life exposure to microbes (through modern sanitation, reduced time in nature, smaller families, less farm exposure) impairs normal immune training, predisposing toward Th2-skewed atopic responses. This partly explains why atopic dermatitis prevalence has increased dramatically in developed countries over the past 50 years.
What Atopic Dermatitis Looks and Feels Like
The hallmark features:
Intense itch (pruritus): The defining symptom. Often described as unbearable, worse at night, and more disruptive than the visible skin findings. Sleep disruption from nocturnal itching is one of the most significant quality-of-life impacts of atopic dermatitis – affecting school performance in children and work productivity in adults.
Dry skin (xerosis): Universal. The impaired barrier causes chronic moisture loss. Skin feels rough, tight, and scaly even outside of active flares.
Eczematous plaques: Red, inflamed, sometimes weeping or crusting patches. In active flares, plaques may be intensely red and swollen. In chronic disease, skin may become thickened and leathery (lichenification) from repeated scratching.
Age-dependent distribution:
- Infants: often affects the face (cheeks) and extensor surfaces (outside of arms and legs)
- Children: shifts to flexural areas – the inner elbows, backs of knees, wrists, ankles
- Adults: similar flexural pattern, but also often affects the face, neck, hands, and upper body
Secondary infections: Broken skin from scratching is highly susceptible to bacterial (Staph aureus – “weeping,” crusting, honey-colored crusts) and viral (herpes simplex – “eczema herpeticum,” a medical emergency requiring urgent antiviral treatment) infections.
Triggers That Worsen Atopic Dermatitis
Atopic dermatitis has a complex trigger landscape. Identifying personal triggers through a flare diary can significantly improve control.
Common triggers:
- Irritants: soaps, detergents, fragrances, wool, synthetic fabrics, sweat, chlorine in swimming pools, cigarette smoke
- Allergens: house dust mites (a major trigger for many patients), pet dander, pollen, mold; food allergens (particularly in young children – egg, milk, peanut, wheat, soy)
- Infections: Staph aureus skin colonization, respiratory viruses
- Temperature extremes: heat and sweat; cold, dry air
- Stress: psychological stress consistently triggers or worsens flares through neuroimmune pathways
- Hormonal changes: flares around the menstrual cycle are common in adult women
On food allergies and eczema: The relationship is frequently misunderstood. Food allergies can trigger eczema flares – particularly in young children – but they are rarely the primary driver of eczema in older children and adults. Eliminating foods without confirmed allergy testing rarely significantly improves eczema and risks nutritional deficiency. Allergy testing should guide dietary decisions, not unguided elimination.
Diagnosing Atopic Dermatitis
Atopic dermatitis is a clinical diagnosis – there is no blood test or biopsy that confirms it. The Hanifin and Rajka criteria (or the simplified UK Working Party criteria) are used clinically.
Key diagnostic features:
- Chronic or chronically relapsing itchy skin condition
- Typical distribution for age (flexural in older children and adults)
- Personal or family history of atopy (asthma, hay fever, eczema)
- Onset before age 2 (in children)
Additional supporting features: dry skin, visible flexural eczema, hyperlinear palms, Dennie-Morgan folds (extra skin fold under the eye), keratosis pilaris (rough bumps on upper arms), elevated IgE, positive allergy skin tests.
Severity assessment: Multiple validated scoring systems exist including SCORAD and IGA (Investigator Global Assessment), used in clinical trials and specialist practice.
Treatment: The Modern Approach
Foundation: Emollients and Skin Barrier Repair
Regardless of severity, moisturizer is the foundation of all eczema management. Emollients restore the impaired skin barrier, reduce TEWL, reduce the frequency and severity of flares, and decrease the amount of topical medication needed.
Key principles:
- Apply immediately after bathing (“soak and seal”) while skin is still slightly damp
- Use thick creams or ointments rather than thin lotions (ointments are the most occlusive and effective for very dry skin; creams are more acceptable for daytime use)
- Apply generously and frequently – at least twice daily
- Fragrance-free and dye-free formulations
- Ceramide-containing moisturizers (CeraVe, Cetaphil, Vanicream) specifically support barrier repair
Topical Corticosteroids
Topical steroids remain the most widely used treatment for acute flares – they reduce inflammation rapidly and effectively. They’re classified by potency (Class 1 most potent through Class 7 least potent) and choice depends on location and severity.
Common misunderstandings:
- Steroid phobia is real and leads to undertreated eczema. Appropriate-potency topical steroids used correctly on affected skin are safe. Thin-skinned areas (face, genitals, skin folds) require lower potency; thicker-skinned areas (palms, soles) can tolerate higher potency.
- Side effects (skin thinning, striae) occur with inappropriate long-term use of high-potency steroids on thin-skinned areas – not from appropriate use
- Weekend/intermittent maintenance therapy (applying 2x/week to previously affected areas after control is achieved) reduces flare frequency
Topical Calcineurin Inhibitors (TCIs)
Tacrolimus (Protopic) and pimecrolimus (Elidel) – non-steroidal anti-inflammatory topicals. Particularly useful for sensitive areas (face, eyelids, skin folds) where steroids carry more risk. Can be used as maintenance therapy without the skin-thinning concern of steroids.
Crisaborole (Eucrisa)
A topical PDE4 inhibitor – anti-inflammatory through a different mechanism from steroids or TCIs. FDA-approved for mild-to-moderate atopic dermatitis. Mild stinging on application is common.
Dupilumab (Dupixent) – The Biologic Revolution
Dupilumab is a monoclonal antibody that blocks the IL-4 receptor alpha subunit – simultaneously blocking both IL-4 and IL-13 signaling. It directly targets the central cytokines driving the Th2 immune response in atopic dermatitis.
FDA-approved for moderate-to-severe atopic dermatitis in adults, adolescents, and children as young as 6 months. Administered as a subcutaneous injection every 2-4 weeks.
The clinical trial results were transformative – approximately 50-60% of patients achieved clear or almost clear skin (IGA 0/1) at 16 weeks. Dupilumab also significantly reduced itch scores and improved sleep. It’s currently the most evidence-backed systemic treatment for moderate-to-severe atopic dermatitis.
Newer Biologics and JAK Inhibitors
Tralokinumab (Adbry): Targets IL-13 specifically (rather than both IL-4 and IL-13 like dupilumab). Monthly injections after loading. FDA-approved for adults.
Lebrikizumab (Ebglyss): Also targets IL-13. Monthly dosing after initial loading. FDA-approved; strong sustained efficacy data.
JAK inhibitors (oral):
- Upadacitinib (Rinvoq): FDA-approved for moderate-to-severe AD; impressive efficacy, often faster onset than biologics
- Abrocitinib (Cibinqo): FDA-approved for moderate-to-severe AD
- Ruxolitinib (Opzelura): Topical JAK inhibitor – FDA-approved for mild-to-moderate AD
JAK inhibitors carry class-wide safety considerations (black box warnings covering serious infections, malignancy, cardiovascular events, thrombosis) that require careful risk-benefit assessment – particularly in older patients with cardiovascular risk factors.
Systemic Immunosuppressants (Conventional)
Cyclosporine, methotrexate, mycophenolate mofetil, and azathioprine – used before biologics were available and still used in specific circumstances. Generally second-line behind dupilumab and newer biologics given less favorable long-term safety profiles.
Frequently Asked Questions
Can eczema be cured? For most people, atopic dermatitis is a chronic condition that can be very well controlled but not permanently cured. Some children improve significantly or appear to “grow out of” their eczema by adolescence – though the underlying atopic predisposition often remains. New treatments like dupilumab can maintain clear skin long-term in many patients when continued, but the disease typically returns if treatment stops.
Is eczema related to food allergies? In young children, food allergies (particularly egg, milk, peanut) can trigger eczema flares. The relationship is less prominent in older children and adults. Atopic dermatitis also appears to increase the risk of developing food allergies – through sensitization via the impaired skin barrier (the “outside-in” hypothesis). However, eliminating foods without proper allergy testing often doesn’t significantly improve eczema and isn’t recommended without guidance.
Does bleach bath therapy actually work? Dilute bleach baths (approximately half a teaspoon of regular bleach per gallon of water, for 5-10 minutes, 2-3 times per week) reduce Staph aureus skin colonization and are recommended by the AAD for managing eczema in patients with recurrent infections. They’re not a primary treatment but can be a useful adjunct, particularly when Staph colonization is driving flares.
Can I use the same moisturizer for eczema as everyone else? Not necessarily – eczema-prone skin benefits from fragrance-free, dye-free, simple formulations that include barrier-supporting ingredients (ceramides, glycerin, hyaluronic acid). Many popular “natural” moisturizers contain botanical extracts that can be sensitizers. Fragranced products are a common irritant trigger. Simplest is usually best – check ingredient lists rather than marketing claims.
Why does my eczema always seem to flare at the same time of year? Seasonal patterns in eczema are common. Winter flares are driven by cold, dry air, central heating (which reduces humidity), and increased indoor time with house dust mite exposure. Summer flares can be triggered by sweating, UV exposure, and swimming. Identifying your seasonal pattern allows proactive management – increasing moisturizing frequency before your predictable flare season.
Disclaimer
This article is for educational purposes only and does not constitute medical advice. Atopic dermatitis management should be individualized with a qualified healthcare provider – ideally a dermatologist for moderate-to-severe disease. New prescription treatments including biologics require medical assessment and monitoring.
References
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- Simpson EL, Bieber T, Guttman-Yassky E, et al. Two phase 3 trials of dupilumab versus placebo in atopic dermatitis. New England Journal of Medicine. 2016;375(24):2335-2348. https://doi.org/10.1056/NEJMoa1610020
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- National Eczema Association. Understanding eczema. https://nationaleczema.org/eczema/
- Sidbury R, Davis DM, Cohen DE, et al. Guidelines of care for the management of atopic dermatitis: section 3. Journal of the American Academy of Dermatology. 2014;71(2):327-349. https://doi.org/10.1016/j.jaad.2014.03.030
- Wollenberg A, Barbarot S, Bieber T, et al. Consensus-based European guidelines for treatment of atopic eczema (atopic dermatitis). Journal of the European Academy of Dermatology and Venereology. 2018;32(5):657-682. https://doi.org/10.1111/jdv.14891
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Atopic dermatitis. https://www.niams.nih.gov/health-topics/atopic-dermatitis