21 lousy milligrams.
That's all the egg protein it took to induce an allergic reaction in my eldest son. It wasn't anaphylactic at that level and was controlled with antihistamines, but I can't help but shake the feeling that this is very allergic. 21 milligrams. That's 3/1000ths of an egg, folks!
Not many people know a specific threshold for themselves or their allergic little ones. The reason we found this out was because of a research study. We enrolled Zax in a study at National Jewish Health in Denver to study a new blood test for food allergies. From what I understand, the hope is that the new blood test will not only be more accurate, but may also predict severity.
It was an interesting process. The first day was a screening visit to make sure he was eligible, get his specific numbers, and take blood samples. They were specifically studying egg, milk, and peanut, and Zax is allergic to two of the three.
We started out by putting a numbing cream on his arm (which takes a while to take effect) and then we talked a lot. They took a medical history and did a scratch test for egg and peanut. I liked the way they recorded the numbers from the scratch test--they traced around his reaction with a fine-tip sharpie, then took a piece of packing tape, placed it over his reaction, pulled it off, and then they had an exact copy of the size and shape of his reaction. Very nice way to remember exactly how things went when they come back to his chart months from now.
His histamine control reacted, as it was supposed to, and so did peanut, but egg failed to show up. Suspecting that something was wrong, though, the doc reapplied the egg prick and reset his timer.
No such luck, egg popped up after all. I almost got my hopes up here, but not too much. I, too, suspected that something was wrong with the test and didn't really think his egg allergy had just disappeared. We were there for the egg, after all. They had met their study quota for peanut participants prior to our learning of the study. We first thought we could be grandfathered in since we were already in the study for egg, but later found out that doing peanut wasn't possible.
After the skin test was complete, they did a blood draw. Despite the EMLA cream, Zax said it still hurt. Poor boy. A previous blood draw had gone fine, but this one was uncomfortable in some way. He was brave anyway!
They took his vitals too, and did pulmonary function tests so they would have a baseline for later.
After his initial screening Zax did two double-blind food challenges. In both cases he ate . . .
Check out our whole interesting story, and how the rest of day one with day two and three went here.