Why could allergy to peanut be so fatal in

[Novice]

some cases and not others?

[ajitsmannan]

Different people may have different susceptibility to the peanut and this a peanut will be fatal in certain instances.

[bravomedic]

As said above but just to elaborate...Allergic reactions can be mild or they can be acute and thus life-threatening. Some people will react to peanuts with a mild allergic reaction, such as hives. Others, will have a severe reaction by going into anaphylaxis (or anaphylactic shock), which if left untreated, can lead to death.The best thing a lay person can do for someone going into anaphlyaxis is to call 911. If the person has an epi-pen, follow the directions on it. An epi-pen can save someone's life, but the epinephrine can wear off quickly so be sure that an ambulance is on the way. Treat for shock.