Adult skin tests - how reliable ?

[Bubblesmum]

Hi,
My DD has multiple food allergies - peanut / treenut / egg and milk. We have seen visible reactions on all except treenut but her skin test showed positive for those too.

During my adult life, I've had pretty severe reactions twice - both occasions at a lobster & clams dinner... so ever since I've avoided them thinking I must be allergic to one or the other.

Anyway, decided to have myself tested and low and behold, all shellfish / fish etc was clear BUT I am showing up as being reactive to TREENUTS?

I eat nuts pretty regularly (every other day) as part of museli (Hazelenuts) and walnuts on salads the odd time. I have never reacted to either.

I am going to proceed with blood testing to confirm these findings but now I am wondering a) if skin tests are false positives
b) did the same happen to my DD and is she indeed perhaps NOT allergic to treenuts(She's 5.5 yrs).
c) if I am allergic to nuts, how come I don't react.

Anyone have any similar experience with adult allergies ?

Thanks !!

[Chandra]

a) any kind of test can give false negatives and false positives.
b) Considering how dangerous a nut allergy could be, I wouldn't trust a negative result once a test has confirmed allergy.
c) The fact that you got a positive for nuts when you have not identified a reaction may mean that your reactions may be of a different nature. i.e. I would never had believed how sensitive DS was milk until I saw the huge difference in his behaviour and health once we removed it.

No test is completely accurate, their reliability may depend in many factors. DS have had ELISA, RAST and Skin Prick tests. Something I have found curious is that ELISA and RAST where positive while skin prick test was negative for milk, but you can see his tummy getting bloated just after having a tiny amount of milk.

Another strange result is that the RAST test was negative for wheat, while ELISA and SP indicated an allergy. We never saw a reaction to it, but the weekend we removed wheat from his diet his behaviour was extremely challenging, and... he spends the time running (even around the dining table, ever since! )

[tatt]

one of my children tests positive to almonds but we're pretty sure she's eaten marzipan and been OK. The "gold standard" is a food challenge, all other tests can be wrong. The higher the score when they test your blood the more likely it is that you will react but its not infallible.

If I was you I would continue eating the nuts you eat already but I wouldn't try any new ones. I wouldn't give nuts to a child who tested positive except in hospital as part of a properly organised food trial.

It's posible your child may have outgrown her allergy if she was diagnosed at an early age. About 1 in 5 children diagnosed in infacy outgrow nut allergy. However if you attend any anaphylaxis meetup you will hear stories of children who tested clear and who had a bad reaction afterwards. You could ask for a food challenge for your child if they are prepared to risk it.

[Bubblesmum]

Thanks for your replies.

Re. my daughter, the strange thing is that when tested as a toddler she did not show any reaction to peanuts or treenuts as part of skin tests. But we never gave her nuts ever - told to wait until at least 3 years. Anyway, we tried her with a teeny tiny bit of peanut butter when she was 5 just before starting school as we knew it wouldn't be nut-free (her preschool was) - and as we live in the US, we knew many kids would have PB & Jelly s/wiches for lunch.

Anyway, she visibily reacted badly and immediately to the peanut butter even though she spat it out immediately. 3 days later she was skin tested at the allergist and then the treenut reaction was seen too on the skin tests.

Its a shame there are no 'definitive' tests, isn't it ? Its not that I want her eating nuts but would love not to have to worry about checking for 'may have traces of nuts' etc in everything (esp when we have to eliminate so much already 'cos of the egg/dairy allergy).

Thanks again!