Also, I personally think it's questionable to define POTS, SFN or MCAS as "symptoms" of ME. All of those are diseases of themselves, and can be severe.
Headache is a symptom of ME.
But headache is also a symptom of many other diagnoses.
And you can have a diagnosis of headache, without other diagnoses.
SFN is a symptom of ME.
But SFN is also a symptom of diabetes.
And you can have a diagnosis of SFN, without other diagnoses.
Diagnoses overlap. That is just an annoying fact of life.
We all wish medicine were black and white, and one day it might be, but the unfortunate reality is that we currently have to deal with a lot of grey.
if the ICC says that MCAS or SFN are symptoms of ME/CFS, then it's wrong. The research to demonstrate this hasn't been done yet.
The ICC doesn't say this. Recent research have suggested this.
If the current research happens to be borne out, then a future set of diagnostic criteria might mention it .