Do you also suddenly feel sick? What is this disease that comes on for no reason? (Mast Cell Activation Syndrome)

Do you sometimes feel very sick all of a sudden? It's like having a severe allergic reaction. Maybe your whole body turns red, itches, swells, you get stomach cramps, you vomit, or you have trouble breathing. But these things don't happen because you ate something or touched something. If these things happen for no apparent reason, it could be a condition called `Mast Cell Activation Syndrome (MCAS).` Let's talk about this in more detail today.

What is ``Mast Cell Activation Syndrome (MCAS)''?

Simply put, MCAS is a condition in which a type of cell in our body called ``mast cells'' becomes overactive for no apparent reason, causing severe symptoms. Now you might be thinking, "That's what an allergy is." Yes, an allergy also involves the activation of ``mast cells.'' But an allergy usually has a clear cause . For example, some people get allergic to shrimp, peanuts, or dust mites. But in MCAS, it's difficult to find a specific cause. These symptoms appear suddenly.

In some cases, the activation of these mast cells can lead to a very severe, life-threatening allergic reaction called anaphylaxis. This can cause difficulty breathing and a dangerous drop in blood pressure. If you experience a severe case of anaphylaxis, you should call 911 or go to the nearest emergency room immediately.

Mast cells are like soldiers in our immune system. They help fight off infections. So, it's normal to feel scared when you have these undiagnosed symptoms. But it's normal for mast cells to become activated. For example, mast cells are activated in conditions like allergic rhinitis, asthma, anaphylaxis to medications or foods, and mastocytosis. This is what causes us to experience these annoying, sometimes dangerous symptoms.

However, ``Mast Cell Activation Syndrome (MCAS)`` is a very rare condition . Doctors diagnose MCAS if the following factors are present:

• If you have recurring symptoms that you think could be anaphylaxis for no apparent reason.
• If these symptoms affect more than one of your body systems at the same time (for example, both the skin and the intestines).
• If tests show evidence of mast cells being activated.
• If your symptoms are reduced by medications that target mast cells.

Mast cells and their role

Mast cells are cells of our immune system .Part. Their normal job is to protect our bodies from pathogens (e.g. parasites, viruses) or other harmful things that enter our bodies. These cells sit in our tissues, and when they see something they think is harmful, they release chemicals like histamine, which activates the immune system and tries to fight off the invader.

Sometimes, they react to things they shouldn't react to. That's when we get allergies . But allergies usually cause minor symptoms like itchy eyes and runny nose. What happens in MCAS is that there are more severe symptoms for no apparent reason.

How serious is ``Mast Cell Activation Syndrome (MCAS)''?

The severity of MCAS depends on the symptoms you experience. Some people may have relatively mild symptoms, with only skin symptoms. Others may experience more severe conditions, such as anaphylaxis. Anaphylaxis can be fatal if not treated properly. However, life-threatening reactions to MCAS are extremely rare .

What are the symptoms of `Mast Cell Activation Syndrome (MCAS)`?

MCAS can cause severe, recurring symptoms in different parts of your body. These symptoms may include:

• Low blood pressure.
• Skin becoming red, pink, and warm (`Flushing`).
• Itchy skin.
• Nasal congestion.
• Swelling - especially of the face, lips, eyes, tongue or throat (`Angioedema`).
• Constipation or diarrhea (maybe alternating between the two).
• Stomach pain.
• Difficulty breathing.
• Weakness or fainting.
• Memory loss or difficulty thinking (brain fog).
• Numbness.
• Joint pain.
• Anaphylaxis (a severe allergic reaction with one or more of the above symptoms).

To suspect MCAS, these symptoms must affect at least two of your body systems. That is:

• Nervous system (brain and nerves).
• Respiratory system (lungs and airways).
• Cardiovascular system (heart and blood vessels).
• Digestive system (stomach and intestines).

How does it feel when mast cells are suddenly activated?

If you've ever had an allergy, you probably know what it feels like when mast cells are activated. But for people with MCAS, the condition is more severe than a typical allergy, and it affects multiple parts of the body. Your skin may swell, turn red, start itching, or even bleed. You may have diarrhea and vomiting. In severe cases, your face and throat may swell, and your blood pressure may drop. Remember, if you experience these severe symptoms, you should call 911 or go to the nearest hospital immediately.

What are the causes of `Mast Cell Activation Syndrome (MCAS)`?

MCAS is caused by your mast cells reacting when they shouldn't. The mast cells think that something harmful has entered the body and need to be protected. That's when they release the proteins that cause the symptoms. In allergies, we can figure out what's causing the body to overreact. But in MCAS, it's hard to find a clear reason for the mast cells to release these proteins.

In fact, no one still knows exactly why mast cells are so sensitive to unwanted things.

What are the possible causes of mast cell activation?

Although many things, such as foods and pollen, can activate mast cells and release histamine, it is not possible to say that the severe symptoms of MCAS are caused by a specific allergen. However, you may find that these symptoms are more severe when there are changes in your life or environment, for example, during periods of high stress or when the weather changes. If your symptoms only occur after exposure to a specific thing, tell your doctor. In that case, you may not have MCAS, but an allergy.

How is Mast Cell Activation Syndrome (MCAS) diagnosed?

A doctor may suspect that you have MCAS after examining you, talking about your symptoms, and medical history. Doctors will diagnose you with MCAS if the following conditions are met:

• If you have symptoms of mast cell activation.
• If you respond well to treatments for mast cell activation.
• If tests show signs of mast cell activation.
• If you have a normal number of mast cells in your body (having too many mast cells means you may have another mast cell disorder, such as mastocytosis).

MCAS testing

To check for MCAS, your doctor may do a blood test to check for a chemical called ``tryptase'' in your blood. ``tryptase'' is something that increases when ``mast cells'' are activated. This test will need to be done several times – both when you are well and when you have severe symptoms. But remember, ``tryptase'' can also be elevated in other medical conditions. So ``tryptase'' levels alone cannot tell if you have MCAS. Some people may have higher than expected ``tryptase'' levels even without symptoms.

Your doctor may also perform allergy skin tests or allergy blood tests to check for other causes.

Important: Even if a histamine blood test shows high histamine levels, doctors do not conclude that you have MCAS.

How is Mast Cell Activation Syndrome (MCAS) treated?

Doctors use treatments to diagnose MCAS and reduce your symptoms. If you don't get better with medications that target mast cells, you probably don't have MCAS.

Depending on your symptoms, your doctor may prescribe medications like these:

• Histamine type 1 receptor blockers (Antihistamines) : These are medications used to treat allergy symptoms. Examples: Loratadine, Cetirizine, Fexofenadine.
• Histamine type 2 receptor blockers (antihistamines that reduce stomach acid) : These are given for nausea and stomach pain. Examples: Ranitidine or Famotidine.
• Aspirin : Aspirin can be given to reduce flushing.
• Leukotriene modifiers : These help make breathing easier. Examples: Montelukast, Zafirlukast.
• Omalizumab (XOLAIR®) : This can reduce the risk of anaphylaxis.
• Epinephrine : Doctors use epinephrine to stop anaphylaxis. You can keep an epinephrine injector (EpiPen®, Auvi-Q®) handy in case you experience anaphylaxis.
• Mast cell stabilizers : Medications like cromolyn sodium prevent the release of chemicals from mast cells (degranulation).
• Corticosteroids : These reduce inflammation, open up airways, and reduce fluid in tissues. However, because of the risk of side effects, doctors don't often prescribe steroids for MCAS.

Will Mast Cell Activation Syndrome (MCAS) ever be completely cured?

No, there is no cure for MCAS. If you have MCAS, you will need to manage it with medication.

What is the life expectancy of someone with MCAS?

Doctors expect that most people with MCAS will live as long as someone without it. But because this is a newly diagnosed condition, we can't say for sure how it will affect lifespan.

How do I take care of myself?

Here are some ways you can take care of yourself with MCAS:

• Keep a diary of your symptoms. Write down what your symptoms were, what you ate and drank at the time, and any exposures you had. Think about what was different during these times compared to when you weren't having symptoms. If you notice any patterns, tell your doctor.
• Tell your closest friends, relatives, or people you often hang out with how you would react in this situation, and where your epinephrine injector or other emergency medicine is.

When should I go to the Emergency Department (ETU) ?

Although severe reactions to MCAS are rare, if you experience symptoms of a severe allergic reaction or anaphylaxis, use an epinephrine injector if you have one. Then call 911 or go to the nearest emergency room immediately. Symptoms of anaphylaxis include:

• Swelling of the face, lips, tongue, or throat.
• Difficulty breathing or swallowing.
• Heart palpitations.
• Low blood pressure.

What questions should I ask my doctor?

It may be helpful to ask your doctor questions like these:

• What should I do if this condition suddenly worsens/escalates for me?
• How should I take my medicine?
• How and when should I use my epinephrine injector?
• When should I go to the emergency room?
• When should I come see you again?

Is ``Mast cell activation'' an autoimmune disease?

No, MCAS is not an autoimmune disorder.

Imagine a siren. The security forces are coming. Your ``mast cells`` have detected a danger and are calling for help. But... there is really no danger. Like a pesky clown, your ``mast cells`` are just sounding the alarm bells without any urgency. Instead of protecting you from disease, they are the ones making you sick.

Although we don't know exactly why some people's mast cells overreact, there are ways to manage MCAS. Recognize the early warning signs of a reaction. If you feel like your symptoms are getting out of hand, talk to your doctor. The most important thing is to always carry an epinephrine injector and know how and when to use it. You may never need it, but being prepared for an unexpected reaction can give you peace of mind.

Things you need to know (Take-Home Message)

• Mast cell activation syndrome (MCAS) is a rare condition that causes severe allergic symptoms without an obvious cause.
• This can affect several body systems at once.
• Life-threatening conditions such as `Anaphylaxis` can occur, so seek medical advice immediately if severe symptoms occur.
• Although MCAS cannot be completely cured, symptoms can be controlled with medication.
• Be aware of your symptoms, keep an epinephrine injector handy for emergency use, and inform your family about it.
• If you have any questions about MCAS, don't be afraid to ask your doctor.

` Mast cells, MCAS, allergy, anaphylaxis, histamine, tryptase, immune system