Skin Prick tests

[athomeagain]

What are the measurements of the hives after a skin prick test taken for?

What is the relevance of there size?

When I asked they said that the size doesn't necessarily indicate the severity of a reaction, but the consultant did seem to be commenting on the size of them, which confused me a bit.

Sorry, that doesn't really help, but hopefully someone eles who knows for definite will answer.

Just bumping for you.

I'd be interested in a definitive answer to this too.
DS has had a number of these and I always thought that the size was directly linked to the severity of the allergy. I know that the blood test gives a definite measure of the level of allergic reaction but, like you, I don't know how they correlate the two. To confuse the matter further the skin prick test can give false positives if the child is already reacting to an allergen...

I know that when my daughter had her second set of skin prick tests after 6yrs of having the first lot, the consultant compared the size of the wheals with those of the previous test to see if there had been any change. I just assumed it was an indicator of severity!!

for nut allergy (one I know best) there is research showing that over a certain size (8 mm?) you're likely to react if given nut. Under that and its less conclusive so they may offer a food challenge unless there is a history of severe reaction.

Although tests don't indicate severity of reaction there is normally a relationship between size of wheal and likelihood of a reaction. However it doesn't hold for everyone. Hope that explains why if the wheals decrease in size its seen as good news.

From personal experience you may get worse results if your child is not totally fit.

Thanks Tatt which research is this? the size of my DD wheals are getting worse and she is in very good health.

The size it was they definitely use to see whether you have an allergy/how severe it is completely!
Anything over a 5 is considered an allergy, anything over an 8 could give concern for an anaphylactic allergy.

Allergies do and can change over time as well, so can an allergy worsen. Athomeagain-Are they saying nothing about it when you are going and having them done? You need to ring and ask more questions, if these allergies were food related then ask to see a dietician.

I had a negative to a skin-prick test and a positive to the actual allergen (just to confuse the matter a little more)

Possibly this one, haven't got time to look this morning.

1: Pediatr Allergy Immunol. 2007 May;18(3):224-30. Links
Skin prick testing predicts peanut challenge outcome in previously allergic or
sensitized children with low serum peanut-specific IgE antibody
concentration.Nolan RC, Richmond P, Prescott SL, Mallon DF, Gong G, Franzmann
AM, Naidoo R, Loh RK.
Department of Immunology, Princess Margaret Hospital for Children, Perth, WA,
Australia.

Thanks tatt