HMN 2026: How Stress-activated pathway reveals how nervous system contributes to eczema flare-ups

The mystery of how stress exacerbates atopic dermatitis, more commonly known as eczema, may be closer to being understood. A new study published in the journal Science has identified a specific nerve pathway that helps explain the link.

Stress and the skin

Eczema is a chronic condition that causes dry, itchy skin. It is common in children but can occur at any age, often triggered by environmental irritants, genetic factors, or an overactive immune system. And stress has long been known to make it worse.

To discover exactly how anxious feelings contribute to the intense itching and skin redness characteristic of eczema, researchers led by a team from Fudan University in China studied both human patients and specialized mouse models.

First, they conducted a retrospective analysis of 51 patients who were already diagnosed with eczema. They asked them to complete a questionnaire that categorized their stress levels, measured the intensity and extent of the condition, and took blood samples and biopsies to count different types of immune cells.

They discovered that the higher a person’s stress levels, the more eosinophils (a type of white blood cell that triggers and contributes to inflammation and itching) they had, and the worse their eczema was.

To determine whether stress was the cause of these flare-ups, the research team studied mice with eczema-like skin and exposed them to various stressful situations, such as being placed on a high platform. Just like human patients, there was a significant increase in eosinophils and more severe skin damage.

Next, the scientists genetically engineered mice to have fewer eosinophils or to lack a specific subset of sympathetic nerve cells known as Pdyn+ neurons that are activated by stress.

Unlike other sympathetic nerves, these connect directly to the skin. When either eosinophils or stress nerves were absent, stress no longer worsened the inflammation. This confirmed that both must be present for a stress-induced flare-up to happen.

How stress triggers a flare-up

Using advanced mapping techniques, the researchers discovered that these nerves sent a direct signal to call inflammatory cells to the skin’s surface during stressful moments. Specifically, neurons release a protein called CCL11 that attracts eosinophils to the inflamed skin tissue where an eczema flare-up is occurring.

Once there, the nerves release another signal that triggers these cells to release proteins that cause the skin to become red and swollen.

“Our findings reveal a neuroimmunological mechanism underlying psychological stress–induced exacerbation of dermatitis, emphasizing the Pdyn+ sympathetic-eosinophil axis as a crucial interface between the brain and skin inflammation, with potential therapeutic implications,” commented the study authors in their paper.

If scientists can find a way to interrupt this nerve-to-cell signal, it could become the basis of new medicines that block stress-induced eczema flare-ups.

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