Licking Pacifier to Clean It May Cut Allergy Risk

Marcia Frellick

November 18, 2018

SEATTLE — Licking a pacifier to clean it before giving it to your child might help prevent allergies, according to research presented here at the American College of Allergy, Asthma & Immunology 2018 Annual Scientific Meeting.

Parental sucking of the pacifier might transfer health-promoting microbes from parent to child, said Eliane Abou-Jaoude, MD, from the Henry Ford Health System in Detroit.

She and her colleagues interviewed 128 mothers enrolled in the Microbes, Allergy, Asthma, and Pets (MAAP) birth cohort in the Detroit area. The mothers were recruited to the cohort from January 2014 to August 2016, while they were pregnant. At recruitment, other than some indoor dogs, the allergy risk in participating families matched that of the general population.

Of the 58% of mothers who reported that their child uses a pacifier, 72% reported hand washing the pacifier to clean it, 41% reported sterilizing it, and 12% reported popping it in their mouth to clean it. Mothers could select more than one method of cleaning they used, but 74% reported only one method.

Parental pacifier sucking was associated with lower levels of Immunoglobulin (Ig)E, which generally indicates lower risk for allergy, beginning at about 10 months (= .048) and lasting through 18 months (= .014).

Table. Mean IgE Levels in Children Exposed to Different Types of Pacifier Cleaning
Cleaning Method n IgE Level at 6 Months IgE Level at 18 Months
By mouth 9 3.054 6.853
Without mouth 65 8.634 109.191

Cleaning a pacifier by sterilizing it with boiling water or washing it by hand with tap water did not affect IgE production.

This was only an 18-month study, but the team plans to assess the children again in 4 or 5 years to see whether they have developed allergies, asthma, or eczema, and to correlate those with IgE levels, Abou-Jaoude told Medscape Medical News.

The findings from this study fit with previous research that compared methods of dishwashing — hand washing or dishwasher — and looked at the risk of developing allergies (Pediatrics. 2015;135:e590-e597), said ACAAI President Todd Mahr, MD.

"Homes that used dishwashers had more allergic children than those in which they hand-washed the dishes," he noted. "It gets back to this microorganisms-and-hygiene hypothesis. It may not be bad in the first year of life to be exposed to some of this stuff to build our immune system."

Because it involved 128 mothers, "it was a well-numbered study," he added.

Will Frozen Epinephrine Autoinjector Work?

Another presentation at the meeting assessed whether an epinephrine autoinjector still works if it is accidentally left outside and freezes.

Two investigators — Julie Brown, MD, from Seattle Children's Hospital, and Alex Cooper, PhD, from the Seattle Children's Research Institute — compared 104 pairs of injectors from the same manufacturing lots. One of each pair was frozen for 24 hours and the other was kept at room temperature.

After the frozen devices were thawed, all were injected into marbleized meat to mimic human muscle. The meat samples and devices were then weighed.

Weights were similar in the two groups, indicating that freezing didn't affect how the devices functioned after thawing.

"Many people who use epinephrine autoinjector have been concerned about the current shortage of EpiPens," Anne Ellis, MD, chair of the ACAAI anaphylaxis committee, said in a statement.

"It's important for those who have severe, life-threatening reactions to have confidence in the autoinjector they carry and know they'll work in an emergency. This study showed that even when an autoinjector has been unintentionally frozen, the risk is low that it will malfunction," she added.

The pacifier study received funding from the National Institute of Allergy and Infectious Diseases and the Fund for Henry Ford Hospital. The epinephrine autoinjector study was funded by the Seattle Children's Anaphylaxis Research Fund and a Summer Whitman Internship Grant. Abou-Jaoude, Brown, Cooper, and Ellis have disclosed no relevant financial relationships.

American College of Allergy, Asthma & Immunology (ACAAI) 2018 Annual Scientific Meeting: Poster P252, presented November 17, 2018; Poster P400, presented November 17, 2018.

Follow Medscape on Twitter @Medscape and Marcia Frellick @mfrellick


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.