Egg Allergies and the Flu Shot

Did you know that the flu vaccine is incubated in chicken eggs?

We learned this when Zax was 10 months old. Even before getting to the allergist, our pediatrician told us he would need to get his flu shot directly from an allergist, if at all. The allergist confirmed this, and that first year we learned the standard protocol. We would go in for a visit, where they would perform a skin test with a sample of the flu vaccine. Assuming he showed no reaction to the vaccine, he would then receive the flu shot, followed by a wait for observation. Zax never reacted to the skin prick test for the vaccine, and he never had any adverse reactions to the vaccine itself, either. They also told us that they test all their vials of flu vaccine for the presence of egg protein, and use the vial with the lowest levels for their egg-allergic patients.

About two years ago, the protocol changed. Our allergist’s office told us that the skin test had proven ineffective at predicting who would react to the flu vaccine, so they no longer did that. Instead, they simply gave Zax the injection and then we waited in the office, like before. (I don’t know if this became standard for everyone, or just for people who had tolerated the vaccine without incident before.) Two years ago, and again last year, Zax again tolerated the flu vaccine with no ill effects. With this history in mind, I wasn’t expecting anything different this year.

However, something different did happen.

Zax got his flu shot at the allergist’s office on Monday. Apart from being afraid of needles and the usual flu shot soreness, he showed no adverse effects at the office. His skin was clear at bedtime, too. And when I helped him get dressed Tuesday morning. Tuesday evening, however, when Zax took his shirt off to change into his pajamas, I was shocked to see this on his arm:

The area was red, slightly raised, and warm to the touch. It was about 3 inches across, centered around the area of his injection. “Does it itch?” I asked, knowing the answer already from the fingernail marks I could see across its surface. “Yes,” he said. I forgot to ask him if he remembered how long it had been itching for.

I called our allergist’s office, asking what to do. He was reporting no other symptoms, and his behavior was consistent with the crazy way he acts every day at bedtime. Was this a Benadryl situation? A Hydrocortisone situation? Claritin? What should we be doing?

The on-call doctor got back to me quickly, and on his advice I gave Zax Claritin, Ibuprofen (for the inflammation), and Hydrocortisone. I also outlined the red spot in pen so we could see if it grew or shrank. And then I was supposed to call our office in the morning to follow up.

This is new territory for me (and although it’s scheduled to post on Wednesday at 6:00, I’m penning this late in the evening, which is the hour at which the Boogey Men come out) so my mind in running at full speed. I honestly wasn’t expecting Zax to have a reaction, and certainly not one 29 hours post-shot. I don’t know what this means for the future. Will Zax still get flu shots, but in two half-doses? (I vaguely remember that this was an option if he had a positive skin test to the vaccine, but that memory is five years old now.) Is he likely to react again in the same way if he gets another flu shot, now that he’s reacted to one? Is he likely to react worse the next time he gets a flu shot? (Food reactions often go that way, why would injecting it directly into the body be any different?) Will Zax simply not get flu shots anymore? That would put us at the mercy of herd immunity, which is waning these days with all the anti-vaccine sentiment going around. And people do die from the flu. We don’t want an anaphylactic reaction to a vaccine though, either. How do we mitigate the risks? And does a histamine reaction to a vaccine reduce the body’s ability to develop the desired immune response?

I guess I have a lot of things to discuss with the allergist tomorrow.

As I write this, it’s 11:00pm. I’ll check on Zax before I go to bed, and evaluate again in the morning. I’m still planning on sending him to school as long as he isn’t worse. These allergies keep sending me curve balls.

Same allergy. New symptoms. New concerns. *sigh*