Maloney JM, Chapman MD, Sicherer SH. J Allergy Clin Immunol. 2006;118:719–724

PURPOSE OF THE STUDY. To determine the time course of major peanut allergen (Arah1) persistence in saliva after ingestion of peanut butter and to evaluate mouth-cleansing interventions to reduce salivary peanut allergen.

STUDY POPULATION. A convenient sample of adults without peanut allergy.

METHODS. Thirty-eight individuals ingested 2 tablespoons of peanut butter, and saliva was collected at various time points. At another time, samples were collected after 5 interventions (brushing teeth, brushing and rinsing, rinsing, waiting then brushing, waiting then chewing gum). Detection of Arah1 was performed by a monoclonal-based enzyme-linked immunosorbent assay (detection limit: 15–20 ng/mL).

RESULTS. Salivary peanut allergen Arah1 varied considerably immediately after ingestion but included levels expected to invoke reactions (as much as 40 μg/mL). Most (87%) subjects with detectable peanut after a meal had undetectable levels by 1 hour with no interventions. None had detectable levels several hours later after a peanut-free lunch. This result indicates (with 95% confidence) that 90% would have undetectable Arah1 in saliva under these circumstances. All of the immediate interventions reduced salivary Arah1, in some cases by >95%, but Arah1 remained detectable in ∼40% of the samples (although typically below thresholds reported to induce reactions).

CONCLUSIONS. Patients with peanut allergy require counseling regarding the risks of kissing or sharing utensils, even if their partners have brushed their teeth or chewed gum. Advice to reduce risks, although not as ideal as total avoidance, includes waiting a few hours plus eating a peanut-free meal.

REVIEWER COMMENTS. Passionate kissing was reported to cause allergic reactions to foods, including anaphylaxis. Waiting several hours and ingesting a peanut-free meal were more effective at reducing salivary peanut protein concentration than simple, immediate interventions. Teenagers with peanut and other food allergies need to be reminded that to stay safe, restraint and patience are necessary even in the most intimate situations.

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