Teenagers with allergies have to let their friends know.

A Quebec teenager with a peanut allergy has died after kissing her boyfriend who had eaten a peanut butter sandwich hours earlier.

Fifteen-year-old Christina Desforges died Monday. She went into anaphylactic shock and in spite of being given an adrenalin shot, could not be revived.

Desforges lived 250 km north of Quebec City in Saguenay.

The official cause of the teen's death has not yet been released.

Pediatric allergist Karen Sigman told CTV's Tania Krywiak if peanuts are still on the tongue or the lips, they can still cause a reaction.

Sigman says teenagers with allergies have to let their friends know.

"If they're going to be dating somebody that they have to tell the people they're close to that they're allergic to make sure the people they're with aren't in contact with those nuts or peanuts," Sigman said.

Parents of children with nut and peanut allergies have the added pressure of constantly watching what their offspring are eating.

Terri Elituv, mother of 12-year-old Jake Elituv, told CTV News they always watch out for snacks that include peanuts, or traces of the legume.

"Everything is just sort of fraught with this underlying tension, you're anxious about what he's going to have, what he could touch," she said.

Elituv's other concern is what happens when her son becomes more independent in his teen years -- and might not share his allergy concerns with friends at parties.

Desforges' parents are planning a memorial service Saturday.