Mast Cell Activation Syndrome (MCAS) and Gd toxicity

In a recent blog I described that Acute Hypersensitivity Reaction (AHR) (Mast cell reaction) can exist as an overlap condition with GDD (T-cell dysregulation).

Earlier studies on AHR that described failure of steroid treatment ,or recurrent AHR (also described for iodine contrast, used in CT), some of these failures may be actually early reporting of GDD. But, what is recurrent AHR: Mast Cell Activation Syndrome. MCAS has not been specifically tied to GBCA use, and in my opinion GBCA toxicity is just one of many potential causes of MCAS.

MCAS, like GDD, is a relatively newly described condition, and as such also is thought of with some skepticism. Treatment of MCAS related to Gd toxicity, just as with GDD, probably chelation with DTPA is part of the treatment plan. Otherwise in general, MCAS is not cured, but managed. Fortunately MCAS is mainly annoying, and uncommonly a serious condition that may result in anaphylaxis. Important management, as with GDD, to avoid other stressors that bring on symptoms (Histamine release with MCAS and Flare with GDD)- obvious stressors for both, and therefore important to try to control are anxiety and stress.

Antihistamines are used to treat MCAS- I would use a generic one (cost reasons, and not clear prescription has great benefits) generic benadryl, maybe generic xyzal better. Singulair (generic montelukast) is prescription but has additional antileukotriene properties (but be aware of night mares and depression as side effect). Antihistamines also form part of Frame drugs for GDD, but I am not sure how important antihistamines are with GDD, unless co-existent MCAS is a prominent component of the patient's symptoms.

So MCAS probably relatively commonly coexistent with GDD - reflecting Gd toxicity activating two families of immune cell lines.