Mast Cell Activation Syndrome MCAS

Mast cell activation syndrome (MCAS) is when you have unexplained episodes of severe symptoms like swelling, diarrhea, vomiting, flushing and itching. Unlike allergies that happen with a specific exposure, MCAS episodes happen without a clear trigger.

In some cases, mast cell activation can cause anaphylaxis, a severe allergic condition that can be life-threatening. It can cause you to have trouble breathing and drop your blood pressure to dangerously low levels. Call 911 (or your local emergency service number) or go to the nearest emergency room if you're experiencing severe anaphylaxis.

Mast cells are a type of immune cell responsible for immune reactions. For instance, conditions like allergic rhinitis and asthma, allergic reactions (like anaphylaxis to drugs or food) and mastocytosis all activate mast cells. This causes them to release proteins that give you symptoms that are bothersome at best, and dangerous at worst.

Other common conditions can also cause unexplained symptoms. It's important to discuss your concerns with your provider. They'll make sure you get a complete workup with a specialist, like an allergist. An allergist is a type of doctor who can diagnose and manage many types of allergic conditions.

But mast cell activation syndrome is rare. Healthcare providers diagnose mast cell activation syndrome if:

• You have repeated symptoms of possible anaphylaxis without a clear trigger
• You have more than one body system affected at the same time
• Tests show signs of mast cell activation
• Mast cell medications provide relief from your symptoms

(CREDITS: Cleveland Clinic)