Mast Cell Activation Syndrome (MCAS) vs Histamine Intolerance

Are you wondering if your histamine intolerance or allergic reactions are actually an issue with your mast cells? Or maybe you’ve experienced chronic symptoms that seem like allergies for as long as you can remember?

Histamine is an important but potentially dangerous mast cell mediator and part of the immune system response. Histamine is secreted by mast cells into surrounding connective tissues when there’s an exposure to an allergen.

Mast cells release histamine works by increasing the permeability of blood vessels and allowing white blood cells and proteins to access affected tissues more easily.

Histamine intolerance is a condition that’s growing in recognition.

However, it is mostly considered a part of a much wider problem which is defined as Mast Cell Activation Syndrome (MCAS), a situation in which part of the innate immune system becomes hyperactive and as a immune response releases multiple inflammatory mediators, of which histamine is one.

Histamine intolerance is considered to be present when there is just too much histamine in your body for it to cope.

This is further exacerbated by the fact that histamine is also present in many foods and so a person’s histamine burden may be further amplified by their diet.

This histamine isn’t broken down due to a DAO gut enzyme deficiency, or a HNMT deficiency in the liver.

A comprehensive guide regarding the low-histamine diet can be found here.

How MCAS differs from histamine intolerance

Mast Cell Activation Syndrome is often confused for histamine intolerance. The difference between the two is that when a person has MCAS, their mast cells secrete many mediators, not just histamine.

Though, histamine release is still a major component of MCAS it’s only a piece of the puzzle.

Histamine intolerance is actually a subset of MCAS. If you’ve discovered you’re histamine intolerant or recently received a diagnosis, you should also be tested for MCAS.

Conditions associated with MCAS

Because MCAS is a multisystem condition throughout the body with inflammation at it’s core, it’s been associated with a number of other conditions including:

• Chronic inflammatory response syndrome (CIRS)
• Irritable bowel syndrome
• Gut dysbiosis – the gut is rich in mast cells and home to over 70% of the immune system. Parasites, bacteria, fungi, and parasites can all trigger gut mast cells.
• Obesity
• Diabetes
• Asthma and allergies
• Autoimmune diseases (such as lupus, rheumatoid arthritis, and Hashimoto’s)
• Candida overgrowth
• Celiac disease
• Parasite infections
• Skin conditions such as eczema and psoriasis
• Food intolerances and allergies
• Gastroesophageal reflux (GERD)
• Infertility and endometriosis
• Postural orthostatic hypotension (POTS)

If you’ve been diagnosed with one of these associated conditions, it could mean that being diagnosed with MCAS is more likely.

Make an appointment with a doctor who specializes in MCAS treatments and begin the diagnostic process.

It can be somewhat of a journey, but once you know you have MCAS there’s a lot that can be done to relieve your symptoms (like using Mast cell stabilizers) and improve your life.

For a comprehensive guide on Mast Cell Activation Syndrome, you can read my in-depth article, Mast Cell Activation Syndrome and Mast Cell Histamine: When Your Immune System Runs Rampant.

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Resources:

https://www.ncbi.nlm.nih.gov/pubmed/25773459

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4507480/

https://www.ncbi.nlm.nih.gov/pubmed/15462834