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MCAS: Respiratory symptoms

Pharyngeal (throat) symptoms are quite common in MCAS and as usual, highly variable. Burning, painful, and irritated throats are frequently reported, and often automatically treated as viral infection or Strep throat, with no culture or negative culture. This pain can be chronic or intermittent. A chronic tickle in the throat or need to clear the throat is often present. Sinus congestion can lead to postnasal drip.

Sometimes MCAS reactions are localized to the throat, inhibiting ability to swallow or sometimes even breathe. This symptom is due to angioedema, and if breathing difficulty is observed, emergency treatment with epinephrine is required.

The most frequently noted lower respiratory symptom is a low level difficulty of breathing. This often presents as occasional wheezing, or feeling like you can’t get a deep breath. Patients rarely have severe wheezing, though it does sometimes happen. Chest x-ray and pulmonary function testing are usually normal.

Chronic non-productive cough affects a small portion of MCAS patients. They are often diagnosed with reactive airway disease for lack of a better explanation. Prostaglandin D2 is a potent bronchoconstrictor, approximately 10 times more potent than histamine, and is responsible in part for respiratory symptoms.

Mast cells have been implicated a variety of pulmonary pathologies, including COPD and pulmonary hypertension. Allergic asthma is not uncommon in MCAS patients and this population often reports successful treatment with Xolair.


Afrin, Lawrence B. Presentation, diagnosis and management of mast cell activation syndrome. 2013. Mast cells.

Anand P, et al. Mast cells: an expanding pathophysiological role from allergy to other disorders. Naunyn-Schiedeberg’s Arch. Pharmacol. 2012 May.