The dreaded Eczema Itch Cycle that keeps you from healing

Step 1: Barrier Dysfunction (The Starting Weak Link)

In eczema patients, the skin barrier is compromised.

Often due to: • Reduced filaggrin protein • Impaired lipid layer (ceramides) • Increased transepidermal water loss • Microscopic cracks in the epidermis

This leads to: • Dryness • Increased penetration of irritants • Increased allergen exposure • Microbial colonization

The skin becomes “leaky.”

Step 2: Bacterial Overgrowth (Especially Staph)

Damaged skin allows overgrowth of:

Staphylococcus aureus

Up to 90% of moderate-severe eczema patients have heavy Staph colonization.

Staph does several things: • Produces toxins (superantigens) • Activates immune cells directly • Increases IL-4 / IL-13 signaling • Disrupts tight junctions further • Reduces skin barrier proteins

It actively worsens the barrier defect.

Step 3: Immune Activation (Th2 Dominant)

Eczema is primarily a Th2-driven immune condition.

Key cytokines include: • Interleukin-4 • Interleukin-13 • IL-31 (itch mediator)

These cytokines: • Suppress barrier repair proteins • Increase inflammation • Increase nerve sensitivity • Promote IgE/allergic signaling

The immune system reacts excessively to minor triggers.

Step 4: The Itch Signal (Neuroimmune Crosstalk)

IL-31 and other mediators stimulate skin nerve fibers.

Nerve endings become hypersensitive.

Even: • Heat • Sweat • Fabric friction • Stress • Minor irritation

…can trigger itch.

And itch in eczema is not mild — it’s neurologically amplified.

Step 5: Scratching

Scratching causes: • Mechanical barrier destruction • Microtears • More water loss • More bacterial penetration • More immune activation

Scratching releases: • Substance P • Histamine • Additional cytokines

Which increases itch further.

Step 6: Increased Infection Risk

Because barrier + immune balance are compromised:

Eczema skin is more prone to: • Bacterial infection (impetigo, cellulitis) • Viral infection (eczema herpeticum) • Fungal colonization

When infection begins: • Swelling increases • Redness spreads • Oozing appears • Immune response escalates

The Full Cycle in One Loop

1.	Weak barrier
2.	Bacteria overgrow
3.	Immune activation
4.	Nerve sensitization
5.	Itch
6.	Scratch
7.	Barrier worsens
8.	More bacteria
9.	More immune activation

Repeat.

Why Barrier Repair Is So Important

Because if you break the cycle at the barrier level: • Less bacterial overgrowth • Less immune triggering • Less nerve activation • Less itch

That’s why eczema management focuses heavily on: • Moisturization • Barrier lipids • Infection control • Targeted immune modulation

Not just systemic anti-inflammatory diets.