I don't feel super comfortable providing the actual names of my treating physicians. I consider that to be confidential information. But he was and still is a consultant immunologist.
Diagnostic tools used included frequent bloods (looking for, amongst other things, inflammation markers), anaesthetised endoscopies, several appointments with a nutritionist while following an elimination diet, and a bunch of other stuff I can barely remember.
The problem that they were trying to solve was that my body was treating certain foods as if they were toxins. I wasn't allergic to them in the traditional anaphylactic sense, but clearly couldn't tolerate them at all. This all got tangled up with HRT because I couldn't tolerate that either (uncontrollable high blood pressure). It became even more complicated due to a variety of other issues until the doctors couldn't really work out what were the causes and what were the symptoms.
The other thing the doctors relied on was my medical history, which is a bit strange from childhood in terms of my responses to various medications and illnesses - e.g. I can't metabolise a certain kind of anaesthetic and an straight up allergic (in the traditional sense) to a bunch of antibiotics. Combined with this was a history of amenorrhea and psychosis relating to hormone function.
The immunologist I saw (and who my daughter saw recently) thinks / thought that it was all connected to immune dysfunction - which is possibly inevitable because he's an immunologist so of course he thinks his discipline holds the key.
There's got to be immunology clinics in Scotland, otherwise no one north of the border would be receiving treatment for things like rheumatoid arthritis.