Brushing teeth or waiting hours after eating may not prevent some with food or medicine allergies from triggering a reaction with a kiss, U.S. allergists said. Allergist Dr. Sami Bahna, past president of the American College of Allergy, Asthma and Immunology, said allergists recommend the non-allergic partner brush, rinse and avoid the offending food for 16 to 24 hours before smooching with someone who is highly allergic to that food. Even those steps may not help in some cases, Bahna said. \"If you have food allergies, having an allergic reaction immediately after kissing someone who has eaten the food or taken oral medication that you are allergic to isn\'t highly unusual,\" Bahna said in a statement. \"But some patients react after their partner has brushed his or her teeth or several hours after eating. It turns out that their partners\' saliva is excreting the allergen hours after the food or medicine has been absorbed by their body.\" \"Kissing\" allergies are most commonly found among people who have food or drug allergies. Symptoms include swelling of the lips or throat, rash, hives, itching and wheezing. Food allergies affect 2 percent to 3 percent of adults and 5 percent to 7 percent of children in the U.S. population, or more than 7 million people, the American College of Allergy, Asthma and Immunology said. Bahna said in one case, a 30-year-old male with a peanut allergy who has had recurrent anaphylaxis -- a life-threatening allergic reaction -- developed lip swelling and itching in his mouth when his girlfriend kissed him. She had eaten peanuts 2 hours earlier, brushed her teeth, rinsed her mouth and chewed gum prior to seeing him, Bahna said.