Skip to main content

Mast Cell Activation Syndrome

Common Comorbidity with POTS

Mast cell activation syndrome (MCAS) is also commonly associated with POTS and can present in a wide variety of ways.  Mast cells are normally found throughout the body, and are most famous for their role in allergy and inflammation.  In the case of mast cell activation syndrome, the mast cells are frequently releasing too much histamine.

MCAS Symptoms

The symptoms of mast cell activation syndrome include:

  • Recurrent abdominal pain
  • Flushing
  • Itching
  • Nasal congestion
  • Coughing
  • Chest tightness
  • Wheezing
  • Lightheadedness
  • Diarrhea

Blood and urine tests can be run to confirm this diagnosis including N-methyl histamine and prostaglandin D2 among others in a 24 hour urine sample.  Allergists or immunologists are most likely to understand, diagnose, and treat MCAS.

Perhaps most importantly, people with mast cell activation syndrome will see an improvement in the above symptoms when they take a combination of Histamine-1 (Zyrtec, Benedryl) and Histamine-2 (Pepcid-AC) antagonists.  Talk with your doctor about trying this regimen for a week to see if your symptoms improve.

The Tryptase Controversy: Is it Necessary to Diagnose MCAS?

We recommend Dr. Artur Fedorowski’s article on the tryptase controversy (Kohno et al. 2021) which does a beautiful job explaining the controversy and how tryptase levels are not a good predictor of MCAS in the POTS population, the link between MCAS and POTS, and some first steps for treatment.

Learn More with Mast Cell Matters on The POTScast

Click here to listen to episodes of The POTScast that focus specifically on mast cell activation syndrome.