In this episode of The Histamine Well, Joanne Kennedy explores the hidden connection between stress, cortisol and histamine intolerance. She explains how chronic activation of the stress response can influence mast cells, increase histamine release and contribute to symptoms such as itching, flushing, headaches, sinus congestion, digestive discomfort and skin reactions.

You’ll learn how the hypothalamic-pituitary-adrenal (HPA) axis responds to perceived stress, why cortisol is beneficial in the short term and what may happen when stress becomes persistent. Joanne also discusses glucocorticoid resistance—a state in which the body becomes less responsive to cortisol’s anti-inflammatory effects—and how this may contribute to ongoing inflammation and increased mast cell reactivity.

The episode also takes a closer look at the autonomic nervous system and the important role of the vagus nerve. When vagal tone is reduced, the body may struggle to move out of fight-or-flight mode and activate its natural anti-inflammatory processes. This can help maintain the cycle between stress, inflammation, mast cell activation and histamine release.