Gi issues and burning facial flushing. i suspect mcas.(dysautonomic) allergist wont test. what kind of md looks into this condition?

MCAS : MCAs is related to high histamine levels. Trestment often involves antihistamines such as benadryl or hydroxizine. I would try to find a functional medicine physician. Often the immune system can be dysregulated due to stress, poor sleep and dietary imbalances. You may want to try a low histamine diet. I would consider checking a 5 HIAA level urine test for carcinoid.