Where can I find a statistic for the number of children who died from allergies causing anaphylaxis in the u.S.?

Only overall numbers. The incidence of anaphylaxis in children is unknown. Estimates of anaphylactic deaths (from drugs, foods, insect stings, and latex) in the us are 0.002 percent annually (2 per 100, 000): 500 fatalities from penicillin anaphylaxis; 40 fatalities from bee stings; 125-150 from food anaphylaxis.