So your child or you yourself have reacted to nuts. You are in good company, and you should be able to get help of all sorts to have some idea of how serious the problem is and to prevent disaster if that is a risk (it probably is, at least to some extent), and most importantly to fight disaster effectively if it seems to be occurring. Few people indeed die from allergy to nuts, but those few do die, so the danger has to be taken seriously.
Here is some information to help. Other sources of information are:

The Anaphylaxis Campaign
A national charity and self-help organization. Join it. Its newsletter and meetings will be invaluable to you.
They publish "Cyril the Squirrel", a book on nut allergy and anaphylaxis for children.

Address: (since November 1997)

The Rd
FarnboRidges
2 Clockhouse rough
Hampshire
GU14 7QY
UK