What Washing Dishes by Hand May Do for Your Child's Allergies

Allergic diseases like eczema, asthma and rhinoconjunctivitis were more common among children in homes where dishwashers were used

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) A simple decision like whether to use a dishwasher may affect your child's allergies.

Washing dishes by hand rather than putting them through the dishwasher may help children steer clear of allergies, a new study found.

“In families who use hand dishwashing, allergic diseases in children are less common than in children from families who use machine dishwashing,” wrote the authors of this study, led by Bill Hesselmar, MD, PhD, of the Queen Silvia Children’s Hospital in Gothenburg, Sweden.

These researchers noted that washing dishes by hand may leave more germs behind, exposing children to bacteria that can cause disease.

Allergies occur when the body reacts to foreign objects it meets that don’t bother most people. These include pet dander, mold and pollen, among others.

For their study, Dr. Hesselmar and colleagues sent surveys to more than 1,000 families in Sweden with children aged 7 to 8.

Parents noted what allergic diseases they had seen in their children, such as eczema, asthma and allergic rhinoconjunctivitis. Eczema is when the skin becomes swollen or irritated. Asthma causes the airways to narrow. Allergic rhinoconjunctivitis is when the membranes of the eyes and nose become inflamed, which can lead to a runny nose or red, irritated eyes.

These families also answered questions about their eating habits.

Dr. Hesselmar and team found that 38 percent of children from families that used a dishwasher had eczema — compared to 23 percent of children whose families washed dishes by hand. Only 1.7 percent of children from hand-dishwashing families had asthma , but 7.3 percent of children whose families used dishwashers had asthma. Allergic rhinoconjunctivitis was also more common in families that used dishwashers than in those that handwashed (12.9 percent versus 10.3 percent, respectively).

In an editorial about this study, Laurence E. Cheng, MD, PhD, and Michael D. Cabana, MD, professors at the University of California, San Francisco, wrote that this study raised questions. They called for more research.

Drs. Cheng and Cabana also noted that this study had some limitations. They said many factors could account for the findings, such as the possibility that parents with sensitive skin due to allergies might have avoided the harsh soaps and detergents used in hand dishwashing and instead used a dishwasher. Parents may pass allergies down to their children.

"As a result, there may be an observed association with [children with skin allergies] and household use of a dishwashing machine," Drs. Cheng and Cabana wrote.

The study and editorial were published online Feb. 23 in the journal Pediatrics.

The University of Gothenburg and the Swedish Allergy and Asthma Association Research Foundation funded Dr. Hesselmar and team. The study authors disclosed no conflicts of interest.

Dr. Cabana was a member of the Merck Speakers Bureau and served as a paid consultant to Genentech and Boehringer-Ingelheim. The editorial authors received funding from the National Institutes of Health.

Review Date: 
February 21, 2015
Last Updated:
February 24, 2015