Eczema (atopic dermatitis) is a common skin condition that causes dry, intensely itchy skin and rashes. It often starts in childhood but can continue into adulthood. Understanding what causes it and what sets off flares is the first step toward managing it.
Why Do You Have Eczema?
Eczema isn't caused by one single thing. It comes from a mix of genetics, a weakened skin barrier, and an immune system that overreacts.
Genetics
Eczema runs in families. If you have a family history of eczema, asthma, or allergies, your own risk is higher — having both parents with eczema or allergic conditions gives a child a plausibly much higher chance of developing it too.
One key gene involved is filaggrin (FLG), which helps build a healthy skin barrier. When this gene doesn't work properly, skin holds less moisture and lets more irritants and allergens through.
A Weak Skin Barrier
Eczema-prone skin has a "leaky" barrier. It loses water too easily, which causes dryness, and it doesn't block outside irritants, allergens, bacteria, or viruses as well as normal skin. This lets triggers get in more easily and start inflammation.
An Overactive Immune System
In eczema, the immune system can treat harmless things — dust, pollen, certain foods — like threats. This triggers inflammation, which shows up as the itchy, red, bumpy skin patches typical of eczema. A weak barrier plus an oversensitive immune system creates a cycle: exposure causes inflammation, inflammation damages the barrier further, and the cycle repeats.
How to Identify Your Triggers
Everyone's triggers are different. Finding yours usually takes some trial and observation, ideally with a doctor's help.
Food
Food isn't a cure or a cause on its own, but for some people it can bring on flares. Food sensitivities and allergies are common in people with eczema, especially in babies and young children with moderate-to-severe cases.
Common culprits:
- Peanuts, tree nuts, cow's milk, eggs, soy, wheat, seafood, shellfish
- Citrus, tomatoes, and spices like cloves, cinnamon, vanilla
- Nickel-rich foods (canned meats, chocolate, seeds, beans, peas, some black teas) — mainly relevant for dyshidrotic eczema
Reactions can be delayed by hours or days, which makes them hard to pin down. If you suspect food is a trigger, an elimination diet done under medical supervision is the safer way to test it — not on your own, especially for children.
Home Environment
- Irritants: Harsh soaps, detergents, and fragranced products (lotions, shampoos, laundry detergent, fabric softener). Even "fragrance-free" products can contain preservatives that irritate skin. Rough fabrics like wool can also cause problems.
- Allergens: Dust mites, pet dander, mold.
- Physical factors: Cold, dry air strips moisture from skin. Heat and humidity can trigger flares through sweating. Long, hot showers or baths strip natural oils and worsen the skin barrier.
Office Environment
New furniture, fresh paint, carpet, and mattresses can release volatile organic compounds (VOCs) like formaldehyde and benzene. These can irritate skin and contribute to dryness and inflammation. Temperature and humidity swings in office buildings can also play a role.
Out in the World
- Cigarette smoke and general air pollution
- Direct contact with nickel (jewelry, clothing fasteners), bleach (like pool water), latex
- Certain cosmetics, hair products, and nail polish
- Extreme weather, in either direction
Other Factors
- Stress: Chronic stress can make itching and flares worse, partly by feeding the itch-scratch cycle.
- Dry skin: Both a symptom and a trigger. Cracked, dry skin invites inflammation.
- Infections: Broken skin from scratching is more vulnerable to bacterial, viral, and fungal infections, which can worsen symptoms.
- Hormones: Changes tied to your period, pregnancy, puberty, or menopause can affect flares.
Reducing Flares: Practical Steps
- Moisturize often. Apply a fragrance-free moisturizer at least twice a day, and always right after bathing while skin is still damp.
- Keep showers short and lukewarm. Hot water strips moisture from skin.
- Use gentle, fragrance-free cleansers without dyes or alcohol.
- Choose soft, breathable fabrics like cotton or silk. Avoid wool and rough synthetics.
- Control your indoor environment. Use a humidifier in dry months, keep temperatures moderate, clean regularly to cut down on dust mites and pet dander, and ventilate well if you're around VOCs.
- Avoid smoke in all forms.
- Break the itch-scratch cycle. Pat or press itchy skin instead of scratching, keep nails short, and consider covering itchy spots.
- Manage stress with whatever works for you — this could be exercise, breathing exercises, or just downtime.
- Be careful with sun exposure. Brief sun exposure sometimes helps some people, but this varies a lot by individual, and UV exposure carries its own risks. Talk to your doctor before treating sun as part of your routine, and use a fragrance-free sunscreen for anything longer than a few minutes outside.
Talk to a Doctor or Dermatologist
Eczema triggers are individual, and figuring yours out often takes professional testing rather than guesswork — especially before restricting a child's diet or trying treatments with real risks (like extended sun exposure). A dermatologist or allergist can offer:
- Patch testing for suspected contact allergens
- Allergy testing (skin prick or blood tests) for food and environmental allergens
- Supervised elimination diets to confirm food triggers safely
Identifying your specific triggers, combined with a consistent skincare routine and stress management, is what actually moves the needle on flare control.