Mast cell activation syndrome (MCAS) has recently garnered attention due to mast cells’ role in COVID-19 and long COVID. Mast cells are a normal type of immune cell distributed throughout our bodies, including within the bone marrow, blood vessels, respiratory tract, and skin. Mast cells release chemical mediators to coordinate protection against infection or promote wound healing. They may also release histamine, which results in an allergic reaction. The 65 million individuals with long COVID show symptoms strikingly similar to those of MCAS, adding intrigue to this complex and mysterious condition.
Despite growing attention, the actual prevalence and other aspects of MCAS remain controversial, highlighting the challenges in understanding and recognizing this often misunderstood condition. Some sources believe it is rare, with one type of mast cell activation disease affecting 1 in 10,000. Other sources say its prevalence is unknown. Contrastingly, some leaders in the field believe it could affect up to 17 percent of the global population.
