Mast cell activation syndrome is a condition that can cause allergy symptoms and other unpleasant side effects. Here’s what you need to know about managing this condition.

A runny nose, sneezing, or watery eyes are all symptoms of allergic reactions. While these are typically thought to be the result of seasonal allergies, allergic reactions can strike at any time, and for a variety of reasons. While allergy medication can alleviate some symptoms, there could be a more sinister reason behind your sneezing. But when should you see a healthcare professional, and what should you look for?

Here’s everything you need to know about mast cell activation syndrome, some common symptoms, and how you can best manage this condition.

What is mast cell activation syndrome?

Mast cells are blood cells that are part of your immune system and help to fight infections. Mast cells live longer than normal cells, and can be found in connective tissues all through the body, especially under the skin, near blood vessels and lymph vessels, in nerves, and in the lungs and intestines [1].

Mast cells have also been implicated in the pathophysiology of many diseases, including allergy, asthma, autoimmune diseases, gastrointestinal disorders, many types of malignancies, and cardiovascular diseases [2].

Mast cell activation syndrome (MCAS) is a condition that causes the mast cells to be overactive and malfunction [3]. This causes allergy symptoms and a wide range of other symptoms.

What triggers MCAS?

When you come into contact with an allergen, mast cells release chemicals called mediators. Some chemicals are released right away, and some take longer. One of those chemicals is histamine, which might cause allergy symptoms. Mast cells may sometimes be triggered by Lyme disease, environmental toxins like mold, infections, certain medications, fragrances, stress, exercise or even food.


Some symptoms of MCAS include itchy or swollen skin, rashes and/or hives, flushing, wheezing, cough, headaches, bloating, and/or inflammation [4]. People who have this condition might experience a lot of allergy symptoms without a clear cause.

Can you treat mast cell activation syndrome?

Unfortunately, there is no cure for MCAS. However, you can manage this condition by avoiding food triggers, managing stress levels, and using certain medications like H1 or H2 receptor blockers and/or supplements like quercetin and stinging nettle that help stabilize mast cells.

High histamine food list

If you have MCAS, you can be highly reactive to a variety of foods, especially those that are high in histamine. An allergen can trigger histamine production, which may produce allergy symptoms such as sneezing, itching, watery eyes, and rashes. You may find that eating a low-histamine diet can help manage MCAS symptoms.

Here are some high-histamine foods that you may consider avoiding or limiting [5]:

  • alcohol and other fermented beverages
  • fermented foods and dairy products, such as yogurt and sauerkraut
  • dried fruits
  • avocados
  • eggplant
  • spinach
  • processed or smoked meats
  • shellfish
  • aged cheese
  • canned meats like tuna
  • bananas
  • tomatoes
  • wheat
  • canned beans
  • papaya
  • chocolate
  • citrus fruits
  • nuts, specifically walnuts, cashews and peanuts
  • food dyes and other additives


MCAS is a condition that can cause allergy symptoms and other unpleasant side effects. While it can’t be cured, you can manage this condition by avoiding food triggers, managing stress levels, and using certain medications and/or supplements. To learn more about testing, treatment and/or how to find the right supplements for you, please schedule a free discovery session at Pursue Wellness today!

For other health and wellness content, check out these other blogs:

The microbiome, nutrition and mental health: what’s the connection?
Oxidative Stress and the Role of Antioxidants
Why is Vitamin D Important?
Why Should You Work with a Functional Dietitian?


  1. NCI Dictionary of Cancer terms. National Cancer Institute. (n.d.). Retrieved September 30, 2022, from
  2. Krystel-Whittemore, M., Dileepan, K. N., & Wood, J. G. (2016). Mast Cell: A multi-functional master cell. Frontiers in Immunology, 6.
  3. Mast cell activation syndrome (MCAS). American Academy of Allergy Asthma & Immunology. (n.d.). Retrieved September 30, 2022, from
  4. WebMD. (n.d.). Mast cell activation syndrome: Symptoms, causes, and treatment. WebMD. Retrieved September 30, 2022, from
  5. Anthony, K. (2019, March 8). Histamine intolerance: Causes, symptoms, and diagnosis. Healthline. Retrieved September 30, 2022, from