Mast Cell Activation Syndrome
Channel: Naila Goldenberg
Date: 2022-05-13

Mast Cell Activation Syndrome is underdiagnosed condition that is fairly common and affects about 17% of the USA population. It was recognized relatively recently and the diagnostic criteria was first established in 2007 and additional guideline was published in 2019. The symptoms are usually of histamine release and may include any of the organ and system, but more frequently includes pulmonary system with wheezing and asthma-like symptoms, hives, angioedema, diarrhea, fatigue and brain fog and such. 
There is frequently an association of hypermobility, POTS (postural tachycardia) and mast cell activation and frequently this is caused by recently recognized Hereditary alpha-tryptasemia (HAT).
Otherwise, MCAS can be Primary- due to genetic mutation (clonal), Secondary-due to immunoglobuline E (IgE) mediation or idiopathic, where none of the above can be found. 
The treatment usually starts with Histamine blockade by H1/H2 blockers.
Leukotriene receptor antagonists (Montelukast, zafirlukast, and zileuton)
 Inhibition of mediator synthesis (aspirin, zileuton) 
Mediator release (sodium cromolyn) 
anti-IgE therapy (Omalizumab binds IgEs)
Tyrosine Kinases Inhibitor (Sunitinib, Imatinib)-in more severe cases. 
In acute situations we will use Epinephrine/Steroids/Bronchodialators/H1/H2 blockers. 
Low Histamine diet can be helpful as well. 
In case of Secondary MCAS using principles of Functional Medicine can be very useful -addressing underlying root causes like leaky guts/toxicities/infections/stress/sleep ect.