The Complete Long COVID Handbook

The Complete Long COVID Handbook: MCAS and Histamine

Volume 5 of the Series by Robert Groysman, MD

Is Long COVID making your body feel like it's reacting to everything?

For many survivors, recovery from COVID-19 never feels complete. New food sensitivities, rashes, dizziness, brain fog, palpitations, gut upset, or crushing fatigue appear-often without warning. Standard tests come back "normal," yet life feels anything but. The hidden culprit? Overactive mast cells and excess histamine.

In Overcoming Long COVID: Mast Cell Activation and Histamine, Dr. Robert Groysman, MD-an anesthesiologist and Long COVID specialist-explains how mast cells, the body's "first responders," can become hypersensitive after COVID. Once helpful, they begin flooding the body with histamine and other chemicals, triggering chaos across multiple systems.

This book demystifies Mast Cell Activation Syndrome (MCAS) and histamine intolerance in clear, patient-friendly language. You'll discover:

• Why Long COVID triggers mast cell dysfunction-and how it differs from classic allergies
• Common symptoms and hidden triggers-from food and hormones to stress and environment
• Practical diagnostic insights-how to recognize MCAS even when labs look normal
• Step-by-step strategies-including medications, supplements, low-histamine diets, gut healing, and nervous system support
• Tools for daily life-how to manage flares, expand food tolerance, travel, and talk to family and doctors

With science-based explanations and real-world clinical experience, Dr. Groysman offers hope and a roadmap for stabilizing mast cells, calming histamine overload, and reclaiming your quality of life.

If you've been dismissed, told "it's just anxiety," or left searching for answers, this guide will help you connect the dots-and take back control, one step at a time.