Question by Corona: When my son was 4, he tested on a skin prick test as having a slight egg allergy, which I knew he had because?
of a couple of reactions towards mayonaise and meringue. When he was 5 his skin test showed negative but she wanted to wait one more year before giving the okay on a food challenge test. This year, at 6, his skin test and blood test were neg. and we were scheduled for a food challenge test when I had given him a bite of an italian muffaleta without thinking. Well, he had a reaction, not severe, but little whelps around the mouth and itchy. I called and got the ingredients of the sandwich and mayo was the only thing on there I could identify with his allergy. (he is also allergic to tree nuts and shell fish). I canceled his food challenge test because I assumed this meant he still hadn’t outgrown the egg allergy. This was 6 months ago. The office called me to confirm a follow up and I told them I didn’t go through with the test so I wanted to cancel the follow up and explained to the nurse why. There was a message on my machine today from the nurse saying the doctor still wants
my son to come in to take the egg food challenge test on Tuesday. I didn’t get home in time to get this message to call them back, but WHY would she want to go through with this test if he is still reacting to mayo?? Anyone else have similar incidents??
Also, is it possible for the skin test AND the blood test to show negative and for him to still be allergic to eggs, OR is there maybe something else that was in that sandwich he is allergic to??
Best answer:
Answer by jane
Firstly, a negative skin and blood test can occur even if allergy exists. False positives also occur. Testing for foods is not a reliable as testing for things such as pollen.
Secondly, you can develop an allergy at any time even if the foods were previously safe.
Thirdly, generally, if a child is going to outgrow an allergy it occurs when they hit puberty. Likewise, many seniors never had allergies during childhood or adulthood but developed them after the “change of life”. Pregnancy is another major hormonal change that can result in allergies.
Do you really want to subject your child to a reaction – given what you just experienced? I am not sure if you are seeing a pediatric allergist or not but I would recommend finding one that is reputable.
Your son could just be reacting to the egg in the mayo or it could be another ingredient. Often secondary ingredients are not disclosed. For example, icing sugar – corn starch is used to keep it from clumping but that is not disclosed. Chocolate chips is another example where the actual ingredients of the chocolate chips are not stated just that there are chocolate chips.
Generally a food challenge test is used when the wrong food is suspected as the cause of symptoms. Or to prove that a food is NOT the cause of symptoms. They can also be used to discover the degree of sensitivity is another reason for performing food challenges.
A food challenge test would confirm the egg allergy but it would not tell you if there is also not a new allergy to something else.
If it were me I would keep an eye out for new allergies by keeping a diary of foods and their ingredients. As far as the egg, if there has been a concrete correlation of egg to reaction in the past, I would wait until after puberty to introduce it into your son’s diet just to be safe. The less the body is exposed to allergens, the better the immune system and less likely to developing more allergies in a susceptible individual.
What do you think? Answer below!