What Really Causes Eczema? Understanding the Root Problem

If you have eczema (also known as atopic dermatitis), you’ve probably wondered:
✔ Why does my skin flare up?
✔ Why does it feel so itchy and dry all the time?
✔ Is it just allergies or something deeper?

The truth is, eczema is not just a skin problem. It’s an immune system issue combined with a weak skin barrier, and many factors—from genetics to diet—play a role. Let’s break it down step by step.

1. Your Skin Barrier Is Broken

Think of your skin as a brick wall:

• Bricks = skin cells
• Cement = lipids like ceramides

In eczema, the “cement” is weak. Here’s why:

• Filaggrin mutation: Many people with eczema have a gene mutation in filaggrin, a protein that keeps skin strong and hydrated.
• Low ceramides and moisture: Eczema-prone skin has fewer natural oils and moisturizing factors, leading to dryness and cracks.
• These cracks allow:
  ✔ Allergens
  ✔ Irritants
  ✔ Bacteria
  to get inside and cause inflammation.

2. Your Immune System Overreacts

When your skin barrier is weak, your immune system goes into overdrive.

• Acute flare-ups = Th2 immune response dominates
  ✔ Key players: IL-4, IL-13, IL-5 (inflammatory messengers)
  ✔ They reduce filaggrin even more → weaker barrier
  ✔ Increase IgE (allergy antibodies) → more sensitivity
  ✔ Recruit eosinophils → more inflammation
  
  
• Chronic eczema = more immune cells join the fight
  ✔ Th1 and Th17 cells release cytokines like IFN-γ and IL-17
  ✔ Skin becomes thicker and rougher (lichenification)

3. Bacteria Make Things Worse

Did you know 90% of eczema patches contain Staphylococcus aureus bacteria?

• This bacteria releases toxins called superantigens → they make your immune system even more inflamed.
• Normally, friendly bacteria like Staphylococcus epidermidis help balance things out, but in eczema, you lose this protection.

4. The Itch-Scratch Cycle Is Real

Ever feel like you just can’t stop scratching? That’s because of IL-31, an itch-causing molecule that activates nerve cells.

• Scratching causes more skin damage → more inflammation → more itch.
• It becomes a vicious cycle.

5. How Does Diet Affect Eczema?

Food isn’t the main cause of eczema, but it can make inflammation worse.

• Too much sugar: Spikes insulin and increases inflammatory chemicals like IL-6 and TNF-α.
• Processed foods: Contain additives and unhealthy fats that cause inflammation and disrupt gut bacteria.
• Gut-skin connection: An unhealthy gut microbiome can trigger immune reactions that show up on your skin.

6. Environmental Triggers Make It Worse

Common triggers include:
✔ Allergens: Dust mites, pollen, pet dander, mold
✔ Harsh products: Fragrances, sulfates, parabens in soaps and skincare
✔ Weather changes: Dry air, cold, heat

What you can do:

• Use fragrance-free, hypoallergenic skincare
• Keep your home clean and dust-free
• Wear protective clothing in harsh weather

Key Takeaways

• Eczema is not just dry skin; it’s an immune and skin barrier problem.
  
  
• Genes, immune imbalance, bacteria, diet, and environment all play a role.
  
  
• Lifestyle changes (clean diet, allergen control, proper skincare) help prevent flare-ups.
  

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