Strange Allergies that Change From One Day to the Next

My current relapse is re-introducing me to many of the weird and (not-so) wonderful symptoms that were once a constant part of my life and the most recent to reappear are strange allergies that change from one day to the next.  I can't believe I forgot this one.  When I say allergy, I guess I mean intolerance; when certain foods or even scents cause a physiological response.  For me, certain foods irritate my lips, tongue, mouth and throat; causing swelling, itching and rawness.  There are some scents and chemicals that also cause similar reactions; usually an irritation of the throat, nose and ears.  I don't know how common a symptom this is with other ME/CFS sufferers, but it is particularly annoying and really sounds like one of those things that I'm just making up.