Does anyone know anything about delayed allergic responses?

[neolara]

My dd and I saw the allergy specialist today as a few months ago my dd (21 months) reacted with swelling and hives where she was in contact with juice from a cherry tomato. A day or so later she was covered head to toe in eczema with big weeping patches in armpits / elbows / backs of knees etc. Not nice.

My dd had a skin prick test today and did not react at all to tomato, which was obviously good. The doctor said normally a negative response on a skin prick test would suggest no allergy and that the hives / swelling a few months ago would simply have been an irritant response to the tomato. However, she was more concerned by the eczema reaction and said this did suggest an allergic response but a delayed one. Has anyone got a good link to finding out in more detail about this? Or has anyone had experience of this?

you do get a ezcema flare up after a reaction. for us, the hives disapear and develops in to ezcema.

this is the same for my food allergic child and now my hay fever allergic child.

tomato is high in histamine and can cause reactions on contact in ingestion, my sons been told to avoid raw tomatos, when younger couldnt even have tinned, but now can.

Somewhere on here (mumsnet) is a Q&A thread about lactose intolerance. It contains information about delayed allergic reactions and why you can have these but also negative skin tests.

I had terrible excema as a child which turned out to be the result of a delayed allergic reaction to dairy and citrus fruit. I never, ever got hives but within 24 hours of ingestion would get really bad flare ups - all over my trunk, as a pose to elbows/wrists/backs of knees where it was constant. My skin prick tests were always negative for dairy and mildly positive for citrus (I had lots of other allergies that I had positive skin pricks to) and the link was only discovered during an exclusion diet I was put on at 10.

HTH

Thank you all.

BarbarianMum. I found the Q & A thread you referred to and the delayed allergic response described there does seem to be what the doctor thought my dd had. She said the eczema flare up was more alarming than the hives / swelling and it was the eczema that made it likely to be an allergic response, albeit not a typical one.