What Is Histamine?

Published: 25 February 2026

If you have ever experienced unexplained skin flushes, digestive discomfort, or a stuffy nose after eating certain foods, you may have come across the term "histamine intolerance symptoms" during your research. Histamine is a chemical that plays several important roles in the body — but when things go out of balance, it can contribute to a wide range of symptoms that overlap with, and are sometimes confused for, allergies. Understanding what histamine actually does, how it differs from a classic IgE-mediated allergy, and what testing can (and cannot) tell you is an important first step toward making sense of persistent or puzzling symptoms. This article is written for UK readers who want clear, trustworthy information without the hype. Whether you are exploring the possibility of histamine intolerance, managing known allergies, or simply curious, this guide aims to help you understand the role of histamine in the body and where professional support may be helpful.**Medical information