What Triggers Eczema Flares? The 10 Most Common Causes Explained

Eczema (atopic dermatitis) affects over 31 million people in the United States alone. For most of them, the condition follows a pattern of flares and remissions — periods of intense symptoms followed by calmer periods. Understanding what triggers those flares is the most actionable step anyone with eczema can take.

Research published in the Journal of Allergy and Clinical Immunology identifies trigger avoidance as one of the top three most effective long-term eczema management strategies, alongside moisturizing and appropriate topical treatment.

Here are the 10 most common eczema triggers, what the research says about each, and what you can do about them.

What Is an Eczema Trigger?

An eczema trigger is anything that provokes or worsens an inflammatory response in people with eczema-prone skin. Triggers don't cause eczema — the underlying condition is genetic and immune-based — but they activate flares in skin that is already predisposed to inflammation.

Most people with eczema have 3–5 consistent personal triggers. Identifying yours is more useful than trying to avoid every possible trigger simultaneously.

Trigger 1: Dry Skin

Why it triggers flares: Eczema is fundamentally a skin barrier disorder. The barrier in eczema-prone skin has reduced levels of filaggrin — a protein essential for retaining moisture. When skin becomes dry, microscopic cracks form in the barrier, allowing irritants and allergens to penetrate and trigger immune responses.

The research: Studies show that transepidermal water loss (TEWL) — the rate at which skin loses moisture — is significantly higher in people with atopic dermatitis than in those without, even between flares.

What to do: Moisturize at least twice daily with a fragrance-free emollient. Apply within 3 minutes of bathing to lock in moisture while the skin is still slightly damp. This single habit reduces flare frequency more than almost any other intervention.

Trigger 2: Sweat and Heat

Why it triggers flares: Sweat contains sodium, ammonia, and lactic acid — all of which irritate compromised skin barriers. Heat also dilates blood vessels and increases skin temperature, which intensifies itching. Many people with eczema notice that their worst flares coincide with hot weather, exercise, or situations that cause heavy sweating.

The research: A 2019 study found that 65% of eczema patients identified heat and sweating as significant flare triggers.

What to do: Rinse off sweat promptly after exercise. Use lukewarm (not hot) water for showers. Wear breathable, loose-fitting natural fibers. In hot climates, keep living spaces cool during peak flare seasons.

Trigger 3: Harsh Soaps and Cleansers

Why it triggers flares: Most conventional soaps have a high pH (around 9–10), which disrupts the skin's natural acidic mantle (pH 4.5–5.5). This disruption impairs the skin barrier and reduces its ability to retain moisture and fight off irritants. Fragrances in soaps are also among the most common contact allergens.

What to do: Switch to pH-balanced, fragrance-free cleansers. Look for products labeled "for sensitive skin" or "dermatologist-tested." Avoid antibacterial soaps, which are particularly harsh.

Trigger 4: Certain Fabrics

Why it triggers flares: Wool and synthetic fabrics (polyester, nylon, acrylic) cause two problems for eczema-prone skin: physical irritation from rough fibers, and heat/moisture trapping that creates the conditions for inflammation. Even fabrics that seem soft can cause problems if they generate friction or don't breathe.

What to do: Choose 100% cotton or bamboo fabrics for clothing worn directly against the skin. Wash new clothing before wearing to remove manufacturing residues. Avoid fabric softeners, which leave residue that can irritate skin.

Trigger 5: Laundry Detergents and Fabric Softeners

Why it triggers flares: Detergent residue stays in fabric after washing and makes direct, prolonged contact with skin. Fragrances, optical brighteners, and preservatives in many detergents are common contact allergens. Fabric softeners coat fibers with chemicals designed to stay on fabric — meaning more skin exposure, not less.

What to do: Use fragrance-free, dye-free detergents. Run an extra rinse cycle to remove more residue. Skip fabric softener entirely, or use a fragrance-free dryer ball alternative.

Trigger 6: Stress

Why it triggers flares: Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, which alters immune function and promotes inflammatory cytokine release. For people with eczema, this immune dysregulation directly worsens skin inflammation. Stress also disrupts sleep, which is itself a flare trigger (see Trigger 8).

The research: A landmark study found that psychological stress was reported as a flare trigger by 30–40% of adults with moderate-to-severe eczema. Stress doesn't just feel related to flares — it is mechanistically connected through immune pathways.

What to do: Stress management is genuinely part of eczema treatment. Regular physical activity, adequate sleep, mindfulness practices, and addressing sources of chronic stress all reduce flare frequency over time.

Trigger 7: Food Allergens (In Some People)

Why it triggers flares: Food allergies trigger systemic immune responses that can manifest in the skin. The most common food triggers in people with eczema are: eggs, milk, wheat, soy, peanuts, tree nuts, and fish. However, food triggers are more common in children with eczema than in adults — and eliminating foods without confirmed allergy testing often causes nutritional problems without reducing flares.

Important caveat: According to the American Academy of Dermatology, food allergy is a confirmed eczema trigger in only about 30% of children with moderate-to-severe eczema, and is less common in adults. Don't eliminate foods without testing.

What to do: If you suspect food is contributing to flares, keep a food-symptom diary for 4–6 weeks rather than immediately eliminating foods. Consult an allergist for proper testing before making major dietary changes.

Trigger 8: Poor Sleep

Why it triggers flares: Sleep deprivation impairs immune regulation and increases systemic inflammation. It also reduces the skin's overnight repair processes. This creates a difficult cycle: eczema itching disrupts sleep, and poor sleep worsens eczema — making the condition progressively harder to manage.

The research: Studies show that children with eczema lose an average of 2 hours of sleep per night during active flares. Adults report similar disruption.

What to do: Treat nighttime itching proactively — apply a barrier cream before bed, keep the bedroom cool, and use breathable cotton bedding. Managing the eczema itself is the most effective way to improve sleep.

Trigger 9: Environmental Allergens

Why it triggers flares: Airborne allergens — including dust mites, pet dander, pollen, and mold — trigger immune responses that worsen eczema in sensitized individuals. Dust mites are particularly significant: they are present in virtually all homes and are among the most common eczema-associated allergens.

What to do: Use allergen-proof covers for mattresses and pillows. Wash bedding weekly in hot water (above 60°C/140°F). Use HEPA air filters in bedrooms. During high pollen seasons, shower after spending time outdoors. If you have pets, keep them out of sleeping areas.

Trigger 10: Hormonal Changes

Why it triggers flares: Hormonal fluctuations affect immune function and skin barrier integrity. Many women report eczema flares that correlate with their menstrual cycle, pregnancy, postpartum recovery, or menopause. This is because estrogen and progesterone influence both immune regulation and skin hydration levels.

What to do: Track flare timing relative to your cycle. If there's a clear pattern, discuss it with your dermatologist — treatment adjustments timed to hormonal cycles can help. During pregnancy, focus on safe, steroid-free topical options.

How to Identify Your Personal Triggers

The most effective approach is a simple 4-week trigger diary:

1. Note flare timing, location, and severity each day
2. Record what you ate, wore, used (products), and did
3. Note weather, stress levels, and sleep quality
4. Look for patterns after 4 weeks

Most people identify their top 3 triggers within a month. Eliminating even one major trigger typically reduces flare frequency by 30–50%.

FAQ

Can eczema triggers change over time? Yes. Triggers that affect you severely in childhood may become less significant as an adult, and new triggers can develop at any age. Regular reassessment of your trigger list is worthwhile, especially after major life changes.

Is there a universal eczema trigger everyone should avoid? Fragrance is the closest thing to a universal trigger. Fragranced products — soaps, detergents, skincare, air fresheners — are among the most common eczema irritants across all age groups and eczema types.

Can weather trigger eczema? Yes. Both cold, dry winter air (which depletes skin moisture) and hot, humid summer conditions (which cause sweating) can trigger flares. Many people with eczema have seasonal patterns to their condition.

Does scratching make eczema worse? Significantly. Scratching breaks the skin barrier, introduces bacteria, triggers further inflammation, and — over time — causes the skin thickening (lichenification) that makes eczema harder to treat. Breaking the itch-scratch cycle through proactive treatment and barrier restoration is central to effective management.

Can eczema be cured by avoiding all triggers? Trigger avoidance reduces flare frequency and severity but doesn't cure eczema. The underlying immune and barrier dysfunction is genetic. However, consistent trigger management combined with appropriate skincare can allow many people to live largely symptom-free for extended periods.

Related reading: [Eczema Flare Ups – How to Manage, Treat and Prevent Them] | [Eczema on Inner Thighs: Causes, Symptoms, and Steroid-Free Relief] | [Nighttime Itch: 3 Science-Backed Tips for Better Sleep]