Well, if my diagnosis of MCAS is correct (I am still not sure even after Dr. Afrin has told me so), I do NOT have skin lesions.  Nor have I ever.

I have SM and no skin lesions or spots.  I probably do have mild TMEP.  Cutaneous mastocytosis is the most common mast cell disorder diagnosis that involves spots on the skin that can be reddish or brownish.  i don't know that they'd be classified as "lesions," which might be more like a wound.  CM spots will itch and wheal up to a more blotchy, itchy red when  scratched or rubbed.  A simple skin biopsy is used to diagnose CM.