Peanut exposure possible through saliva

By Megan Rauscher

NEW YORK (Reuters Health) - People with peanut allergy and their partners should not kiss, or share utensils, if the partner has recently eaten peanut-containing food, an allergist from New York advises in a report published this month.

Even with brushing, rinsing, or chewing gum, peanut allergen can remain in saliva after eating peanuts, Dr. Jennifer M. Maloney from Mount Sinai School of Medicine told Reuters Health.

It is estimated that 1.7 million Americans are allergic to peanuts.

"Exposure to food allergens through saliva ... can cause allergic reactions in food-allergic individuals," Maloney said, "and it is important for peanut-allergic individuals to be aware of the time course of peanut allergen persistence in saliva."

In a follow up to a previous study on peanut allergen exposure through saliva, Maloney and two colleagues tested the saliva of 38 individuals at various time points after they ate a sandwich containing 2 tablespoons of peanut butter.

Confirming their earlier work, saliva concentrations of the major peanut allergen varied markedly immediately after ingestion, but included levels "expected to invoke reactions," the team reports in the Journal of Allergy and Clinical Immunology.

"After ingesting peanut butter and performing various interventions (such as brushing teeth, rinsing the mouth, chewing gum, and brushing the teeth after a wait period of one hour), peanut allergen concentration decreased to low levels but remained detectable in most saliva samples," Maloney told Reuters Health.

Eighty-seven percent of subjects with detectable peanut in saliva after eating peanut had undetectable peanut allergen levels by 1 hour with no interventions. None had detectable levels several hours later after eating a peanut-free meal.

"Avoidance of peanut containing foods by partners of peanut-allergic individuals is the most effective way to prevent allergic reactions caused by peanut allergens in saliva," Maloney said.

"However, if peanut avoidance by partners is not possible, waiting several hours after ingestion of peanut butter and having one's partner eat a peanut-free meal before engaging in kissing or other kind of saliva exchange was determined to be the most effective method of reducing peanut allergen in saliva," she added.

SOURCE: Journal of Allergy and Clinical Immunology, September 2006.