Discovering the cause of an allergic reaction

[Tigerlillies]

Ds is now 16 months and over the last 3 months he has had raised, red blothes appearing on his belly and it spreads gradually over a day or two up to his arms and over his back. After a few doses of piriton it disappears only to reappear a couple of weeks later.
Since the reaction isn't immediate it will be quite difficult to pinpoint the cause.
Are there some things that I should cut out of his diet straight away or shall I ask my GP for advice?

I'd definately go to the gp - sooner rather than later. you can get piriton on prescription and, if necessary, a referral to an allergy clinic. My ds, 4, frequently gets uricaria (hives) just as you describe and we still cant always fathom out what has caused them but we always have piriton (and epipens) with us whereever we go, just in case,