By Alvin Alexander. Last updated: September 17, 2016
In retrospect, mast cell activation syndrome (MCAS) (or mastocytosis) explains many mysterious health problems. For example, six years ago I took a routine blood test and my doctor found that my Vitamin D level was extremely low, even though I was out in the Sun every day and took a multivitamin supplement, in addition to drinking milk and eating a lot of cheese. Then last year I told my doctor that on four occasions it felt like bones in my feet, hands, and arm had broken spontaneously, but she just looked at me like I was crazy.