Skin prick tests: Worth it? Or should you simply avoid all nuts?

In June 2012, a month and a half after D’s anaphylactic reaction to peanuts, we were given an appointment for skin prick tests at the hospital. We had been told this is when D would be tested for other types of nuts and soya.

The appointment fell on a Wednesday, which (typically!) was D’s day in nursery. So Ian took the afternoon off work and we collected D from nursery at lunchtime, to all troop down to the hospital for the allergy tests.

However, when we met with the doctors that afternoon, we were advised that:

  • Given D had eaten soya (in bread) previously without any problem, the hospital would not be carrying out a skin prick test for soya. Instead, we were to test him at home by first giving him a tiny piece of soya-containing bread, then 15 minutes later a slightly bigger piece, then 15 minutes later a quarter of a round of bread, then 15 minutes later the remainder of the piece of bread. If he showed no signs of a reaction, we could assume he could eat soya and should then continue to include soya in his diet.
  • There was no point in testing D for other types of nuts. The safest approach was for him to avoid nuts completely.

I wasn’t particularly happy about this: I wanted him to be tested for all nuts, really for my own peace of mind. For example, if he tested safe for hazelnuts and crawled out from under a table holding a hazelnut cookie, then my reaction (and stress levels) would be a lot different to if he emerged holding a Snickers bar. The doctor’s view was that we couldn’t assume a “hazelnut” cookie would be peanut free, so our vigilance levels should be the same in either case.

So we walked out of hospital that day, not having had any skin prick tests carried out. I confess I was somewhat confused: if a food didn’t list “peanut” in the ingredients section, but did contain A N Other nut, why couldn’t we assume it was peanut free?

Ian had been doing a lot of reading around the subject on the internet by this point and thought it was probably because of the higher cross contamination risk for nut products (because some manufacturers use the same machinery for grinding peanuts and other nuts).

After mulling it over, I got back in touch with the hospital and asked if we could bring D back to be tested for all nuts. Even if he tested safe for other nuts, we would continue to avoid all nuts. Although I could see the doctors’ logic (“if you’re going to avoid all nuts anyway, then why have the tests?”), I knew that I personally would feel better knowing the full extent of his allergy.

The skin prick test appointment

We didn’t get another skin prick test appointment until October 2012. The doctor wrote a list of the various nuts in a line down D’s forearm. He then placed drops of allergen onto D’s arm and then went back and pricked each into his skin with a plastic peg. Even though I knew the tests were safe, it was still horrible watching that drop of peanut being pricked into his arm, particularly as it was me who had pushed for the tests to be carried out.

The test results showed that D was allergic to peanut. However, he didn’t react to the other types of nuts. What happened next took me by surprise: the doctor told me to introduce the other nuts into D’s diet one by one, starting with hazelnut (given he had been able to tolerate this prior to the peanut reaction).

I felt strangely elated after the tests. Although the results didn’t change much in practice, it just felt like we were getting a better handle on the situation. For me, it’s a case of the more information the better: I would always rather know the full extent of the problem. However, when I relayed everything to Ian, his first thought was “but what about the cross contamination risk”?

We have yet to clarify this with the hospital (and haven’t yet started reintroducing tree nuts).  It may be that we misunderstood the thinking behind the advice on the first appointment. In the meantime, if anyone has any thoughts, I would love to hear from you!

Update (7 June 2013)

We’ve now discussed this further with our doctors – see the follow up post: Some clarity: does peanut allergy mean avoiding ALL nuts?

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