A really good question.  Why do the glutes recommend that people who think that they might be MSG sensitive see an allergist?

A really simple answer.  Because after examining you, and having you tested for allergy to MSG, your average allergist will tell you that "you are not allergic to MSG -- so, clearly, although there is something bothering you, what's bothering you isn't MSG."  That's what your allergist will say.

So you think that you are sensitive to MSG, but your allergist says "not so."  And what are you left with?  Confusion.  That's what the glutes want.  They don't want you to  consider/understand that you might be sensitive to MSG.

It's part their well thought out plan.  In the 1970s, when the glutes pretended to look for brain lesions and not find any, they didn't find any brain lesions because they used inappropriate methods to stain the slides they would have to look at; they looked for brain lesions in areas of the brain outside of the areas where brain lesions had been found by others; and instead of looking for those brain lesions within 24 hours, when evidence of lesions would still have been visible, they waited a day or two so when they would look, they wouldn't find any brain lesions.

That's why the glutes recommend that people who think that they might be MSG sensitive see an allergist.  Your average allergist will look for an allergic reaction.  Your average allergist will look for the wrong thing, and, obviously, won't find it.

Get clear and remember: the reaction brought about by ingestion (or other use) of MSG is not an allergic reaction.  The reaction to MSG is a reaction to a poison.  And the only way to test for MSG-sensitivity is to give the consumer a dose of MSG and observe whether or not the consumer responds with an adverse reaction.