Immune System Overdrive. A Look into Mast Cell Activation Syndrome

By Caitlin Kukta  

At 18, I learned that the world was no longer safe. My bags resembled a pharmacy more than a teenage girl's purse. Antihistamines in one pocket and a list of “safe foods” in my notes app. Some mornings, a banana was a reliable breakfast. Other days, the same fruit could leave me covered in hives and in horrible pain. Sometimes the reactions came with no obvious trigger.  

For years, doctors ignored the signs. I was just anxious. That I had sensitive skin. I was a hypochondriac who needed to relax. But no matter what I tried, the reactions were relentless. It wasn't until I finally saw a specialist, after waiting seven months, that I finally received an answer to what was happening. Mast Cell Activation Syndrome.  

Mast Cells are a vital part of the immune system and are found throughout the body. They play a key role in defending against pathogens, healing wounds, and releasing histamines during allergic reactions. In a healthy body, mast cells activate only when a real threat is present. In someone with a Mast Cell disorder that signaling process is disrupted.  

An easy way to understand MCAS is to imagine your mast cells as the smoke alarm of your body. Their job is to alert the body of threats and respond to them accordingly. When someone has a mast cell dysfunction such as MCAS, their smoke alarm goes off constantly. Even when there is no fire.  

Mast Cell Activation Syndrome is a relatively new diagnosis. Only really gaining traction in the medical world over the last decade. It is considered rare and is notoriously difficult to diagnose. The symptoms are systemic, meaning they can affect nearly every part of the body. Everyone with the disease will present with different symptoms. This makes the diagnostic process extremely difficult and frustrating.  

According to the center for autonomic dysfunction in the young at Connecticut children's medical center, 

“In Mast Cell Activation Syndrome (MCAS), patients have normal or near normal numbers of mast cells but a range of symptoms arising from the unusual activation of mast cells. This is relatively new diagnosis, and the process by which the cells are unusually activated is not well understood” (p.12)  

Because MCAS symptoms often mimic those of more common conditions, Doctors must rule out other common causes before even considering a mast cell dysfunction as a possible diagnosis. Treatment is equally challenging, due to each person's experience being so different. As a result, many patients spend years searching for answers, often feel dismissed or misunderstood by the medical professionals meant to help them.  

The disease remains controversial throughout medical spaces due to its lack of diagnostic structure. There is currently no single test that can definitely confirm MCAS. As Mathew J Hamilton’s explains in Addressing Controversies in Mast Cell Activation Syndrome: Analysis Using the Cluster Instrument,  

“There is no clinically validated test such as a tissue biopsy or detection of a mast cell mutation to confirm the diagnosis. Practitioners rely primarily on a constellation of symptoms that may fit a mast cell disorder and on the clinical response to mast cell-targeting medications.” (Hamilton, p.3)  

Without a definitive test, some clinicians question the legitimacy of the diagnosis or refuse to recognize it at all. For patients, this skepticism can be devastating as it is just another barrier they face during an exhausting search for answers and care.  

Still, progress is being made. There are many doctors who recognize MCAS as a disease and even choose to specialize in treating it. These doctors are the ones who are driving new research and expanding their understanding of the condition.  

According to Mayo Clinic, providers often choose to use a combination of a few medications to help patients manage their symptoms. Usually, a combination of H1 and H2 blockers (antihistamines), mast cell stabilizers, and anti-inflammatory medications.  

Living with Mast Cell Activation Syndrome means living with a level of uncertainty that many people will never experience. Food, environments, stress, and even daily activities can quickly go from ordinary to dangerous without warning. Yet for many patients, including myself, the most painful part of living with the rare disease is not the reactions themselves, but the struggle to be believed.  

As awareness of the disease slowly grows, so does the hope that fewer patients will spend years waiting for answers. New research, clearer diagnostic criteria, and better medical education could mean the world for those living with this complex condition. Being heard matters, and with a disease that hides in plain sight, understanding might be the most powerful treatment we have.  

References  

Mast cell activation disease diagnosis can reveal pi. Immune Deficiency Foundation. (n.d.-a). https://primaryimmune.org/resources/news-articles/mast-cell-activation-disease-diagnosis-can-reveal-pi 

Mast cell activation syndrome (MCAS). Cleveland Clinic. (2025, December 2). https://my.clevelandclinic.org/health/diseases/mast-cell-activation-syndrome