What Causes Eczema Flare-Ups? Triggers, Science, and Smart Shopping Tips

If you live with eczema (most commonly atopic dermatitis), you know the pattern: your skin feels calm for a while, then suddenly it’s red, itchy, and reactive again. These “flare-ups” are usually set off by specific triggers that disturb the skin barrier and ignite inflammation. Understanding what causes eczema flare ups, and how to shop for the right products, can help you reduce future flares and feel more in control. 

Below, we break down the most common eczema triggers, what the latest science says, and practical, e-commerce-ready tips for choosing moisturizers, cleansers, sunscreens, laundry care, and home gear that actually support sensitive, eczema-prone skin.

Eczema flares 101: the barrier–immune–microbe triangle

Three forces tend to team up during flares:

• A vulnerable skin barrier: People with eczema often have a weaker “brick-and-mortar” barrier (sometimes tied to filaggrin gene variants), so water escapes more easily and irritants get in. That’s one reason moisturizers and barrier creams are foundational. 
• Immune overreaction: Everyday exposures (sweat, detergents, allergens) can tip the immune system toward inflammation, leading to itch–scratch cycles and visible rashes. 
• Microbes on the skin: Staphylococcus aureus commonly colonizes eczema skin and is linked with worse disease activity; managing bacteria with evidence-based care (like appropriate prescription meds and, in some cases, dilute bleach baths) may help some patients. 

Bleach baths aren’t magic and the science has evolved: systematic reviews show small average benefits and mixed results versus plain water, and more recent discussion suggests benefits may stem from anti-inflammatory and barrier effects rather than “killing all the bacteria.” If your clinician recommends them, they’re an adjunct—not a standalone—and should be properly diluted. (pubmed.ncbi.nlm.nih.gov)

The most common eczema flare-up triggers (and what to do)

1) Everyday irritants in skincare, soap, and laundry

• Fragrances, harsh surfactants, alcohols, and dyes frequently irritate eczema-prone skin. Choose fragrance-free (not “unscented”) creams/ointments over lotions, patch test new products, and keep showers short and lukewarm. 
• Laundry can sabotage your routine. Use fragrance-free, dye-free detergents and skip dryer sheets/fabric softeners that leave residue. 

Shopping tips:

• Moisturizers: Look for ointments and thick creams with petrolatum, ceramides, hyaluronic acid, colloidal oatmeal, and/or dimethicone. Apply within three minutes of bathing (“soak and seal”).
• Cleansers: Pick pH-balanced, non-soap cleansers without SLS/SLES. 
• Verify with trusted seals: Products with the National Eczema Association Seal of Acceptance are formulated to be eczema-friendly. 

For more trigger basics and day-to-day prevention ideas, see our guide Eczema Flare-Ups: Triggers, Prevention, and Relief. You can visit the Eczema Flare-Ups: Triggers, Prevention, and Relief page to review this resource.

2) Weather, temperature, and humidity swings

• Cold, dry winter air and indoor heating dehydrate skin; heat and sweat in summer can sting and trigger itch. Keep baths lukewarm, moisturize more in winter, and dress in breathable layers to avoid overheating. A room humidifier can help in dry climates (don’t over-humidify). 

Shopping tips:

• Humidifier + hygrometer to maintain indoor humidity roughly 30–50%.
• Breathable clothing and bedding (100% cotton or other smooth, natural fibers) to minimize friction and sweat build-up. 

3) Allergens: dust mites, pollen, pets, and mold

• For some, airborne or indoor allergens worsen eczema. Practical steps include encasing pillows/mattresses, washing bedding weekly in hot water, reducing dust catchers, and keeping windows closed on high pollen days. Results vary by person, but these steps can help if you’re sensitive. 

Shopping tips:

• Dust-mite–proof encasements (tightly woven, breathable), HEPA vacuum filters, and fragrance-free detergents. (eczema.org)

4) Stress and poor sleep

• Psychological stress can exacerbate flares via hormone–immune pathways; many people report more itching during stressful periods. Build a stress-management routine (mindfulness, yoga, short daily movement, consistent sleep). (healthline.com)

If stress is a big trigger for you, you can visit the Can Stress Cause Eczema? | Phoilex page for an easy-to-digest explainer and practical de-stressing ideas.

5) Hormonal shifts (periods, pregnancy, menopause)

• Studies show that a meaningful portion of women notice premenstrual or pregnancy-related worsening of atopic dermatitis, and menopause-related hormone changes can also dry and destabilize skin. Discuss safe treatment adjustments with your clinician during these life stages. (pmc.ncbi.nlm.nih.gov)

6) Sweat, exercise, and sunscreen

• Sweat and overheating commonly trigger itch. Take breaks to cool down, wear moisture-wicking, loose layers, and shower off sweat promptly. For sun protection, mineral sunscreens with zinc oxide and/or titanium dioxide are usually better tolerated on sensitive skin. 

Shopping tips:

• Choose mineral, fragrance-free, broad-spectrum SPF 30+; consider UV-protective clothing for outdoor workouts. 

7) Water exposure: ocean, pool, and hard tap water

• Swimming is a mixed bag. Chlorinated pools may dry or irritate skin for some, yet others feel better after (similar to a carefully diluted bleach bath effect). Either way: apply emollient before, rinse off after, and moisturize within three minutes. Sea water can sting broken skin; many still do fine with good pre/post-swim care. 

Curious about beach days? You can visit the Is Ocean Water Good For Eczema? page to weigh the pros, cons, and prep steps.

• Hard water: Observational studies link hard water to a slightly higher risk of childhood eczema, but installing a home softener hasn’t been shown to improve established eczema severity in randomized trials. Gentle cleansers and thorough rinsing remain key. (pubmed.ncbi.nlm.nih.gov)

8) Infection and skin trauma (scratching, friction)

• Scratching damages the barrier and raises infection risk. If you see signs of infection (oozing, honey crusts, pain), seek care. Skin colonization with S. aureus is common and may relate to severity; your clinician can advise on prescriptions and adjuncts. (pubmed.ncbi.nlm.nih.gov)

9) Food: more complicated than headlines suggest

• Food allergies rarely drive day-to-day eczema flares on their own. Don’t start broad elimination diets without medical guidance—malnutrition is a real risk. Evaluation is considered if eczema stays moderate–severe despite optimized skin care and medication, or if you see immediate reactions after specific foods. 

How to pinpoint your personal triggers (fast)

• Keep a “flare diary” for 2–4 weeks: note skincare used, foods, locations, stress, sleep, weather, pollen/AQI, workouts, and laundry changes. Patterns often jump out quickly and guide smarter shopping and routine tweaks. (my.clevelandclinic.org)
• Consider patch testing for suspected contact allergens (fragrance mix, preservatives, rubber accelerators in gloves, nickel, etc.). (aad.org)

Shop smart: eczema-friendly essentials (what to buy and why)

• Daily moisturizers (cream/ointment): Petrolatum, ceramides, colloidal oatmeal, glycerin, hyaluronic acid, and dimethicone support barrier repair. Apply thickly, at least twice daily and always after bathing. Ointments tend to lock in moisture best. (mayoclinic.org)
• Gentle cleansers: pH-balanced, fragrance-free, no harsh sulfates. Limit hot water; keep showers to 5–10 minutes. (aad.org)
• Mineral sunscreen: Zinc oxide and/or titanium dioxide; fragrance-free SPF 30+; especially important if sunburn has triggered flares. (aad.org)
• Laundry: Fragrance-free, dye-free detergents; skip fabric softeners. Wash new clothes before wearing. Prefer soft, tagless, 100% cotton garments. (aad.org)
• Bedding and encasements: Breathable dust-mite–proof covers for pillows/mattresses if you’re sensitive; launder bedding weekly in hot water. (aad.org)
• Home environment: Humidifier for dry air, but avoid over-humidifying (mite/mold growth). Consider HEPA filters if AQI spikes worsen your skin. Pollution exposure is linked to increased AD symptoms and clinic visits in multiple studies. (medicalnewstoday.com)
• Bath add-ins (optional, individualized): Colloidal oatmeal or baking soda for itch; dilute bleach baths only with clinician guidance; rinse off and moisturize afterwards. (nationaleczema.org)

Evidence-backed routines that reduce flares

• Soak-and-seal: Short, lukewarm bath or shower; pat damp; apply prescription anti-itch/anti-inflammatory cream if directed; then seal everything in with a thick moisturizer. (mayoclinic.org)
• Wet-wrap therapy: For tougher flares, wet wraps over moisturizer/medication can accelerate relief—ask your clinician to teach you the method. (medicalnewstoday.com)
• When to escalate: If your eczema stays moderate–severe despite optimized skin care, or flares frequently, see a dermatologist. Current U.S. guidelines (2023) outline options from non-steroid topicals (TCIs, PDE4 inhibitors, topical JAK inhibitors) to phototherapy and systemic therapies (biologics like dupilumab; oral JAK inhibitors) for appropriate cases. (pubmed.ncbi.nlm.nih.gov)

Helpful Phoilex reads

• For a friendly overview of day-to-day triggers and a prevention checklist, visit Eczema Flare-Ups: Triggers, Prevention, and Relief.
• If you notice flares during busy or anxious weeks, see Can Stress Cause Eczema? | Phoilex for stress–skin science and soothing tactics.
• Planning a beach or pool day? Read Is Ocean Water Good For Eczema? before you go.

Bottom line

Eczema flare-ups aren’t random. They’re usually triggered by irritants (fragrance, detergents, hot water), environmental shifts (dry air, heat and sweat), allergens (dust mites, pollen, pets), stress, hormones, or skin infections. The fastest wins come from simplifying your routine, moisturizing strategically, choosing fragrance-free/mineral products, managing your air and laundry environment, and tracking what sets you off. When home care isn’t enough, today’s treatments—from advanced topicals to biologics—offer powerful options to regain control.

Build a shopping list that supports your skin, keep notes on what helps, and lean on your care team when you need to escalate. Your skin barrier will thank you.

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References and further reading:

• AAD: Choosing moisturizers, avoiding fragrance, bathing tips, clothing/laundry, and indoor/outdoor triggers. (aad.org)
• Cleveland Clinic and Mayo Clinic: trigger tracking, soak-and-seal, humidifiers, bleach-bath how-to. (my.clevelandclinic.org)
• National Eczema Association/Society: bathing therapies, dust mites and household irritants, swimming guidance. (nationaleczema.org)
• 2023 AAAAI/ACAAI Joint Task Force guideline on atopic dermatitis: current treatment landscape. (pubmed.ncbi.nlm.nih.gov)
• Air pollution and AD: reviews and clinical associations with symptom flares and healthcare visits. (pmc.ncbi.nlm.nih.gov)
• Hormonal influences on AD: pregnancy and menstrual cycle studies; menopause considerations. (pmc.ncbi.nlm.nih.gov)
• Hard water and AD: association vs. intervention trial results. (pubmed.ncbi.nlm.nih.gov)
• S. aureus colonization and evolving bleach-bath evidence. (pubmed.ncbi.nlm.nih.gov)

Note: This article is informational and not a substitute for personalized medical advice. If you suspect infection or if flares persist, see a board‑certified dermatologist.