Hi SandraB,
Average reading for my son on IgE is always up in the 1,100 range - very high. This is supposed to be due to hay fever, dust mite, pollens etc. but as it is like this all year round there is more going on than that somewhere. However, some laboratories use different scales to the NHS scales for IgE so you have to go by their scales and see where you fall.
Quercetin is supposed to be natural antihistamine, but I don't think you can take too high an amount of it. It is not as clear cut as nutrtionists tend to say it is. You could try it. Son hasn't used it a lot and we may try it again, but the one time he did try it it tended to give a headache, but then that may have been something else. I believe that Quercetin should be taken with Bromelain to help absorption which of course is no good if you have an allergy to pineapple! Vitamin C is good for stabilising mast cells but again a problem as most IC people have trouble with vitamin C and it can irritate the bladder - even the buffered or Ester C. type.
But on the gluten/coeliac tests - they are not really looking at IgE or IgG - there are different markers of immunoglobulins and things like transglutaminase markers that they are assessing. If your Secretory IgA is low all tests will come back negative. Maybe with gluten you have to see if it has any effect if you withdraw it and then do a challenge by having lots of it to see if any pattern can be found.