• Amelia Colley, M.D., FAAP
  • Philip Dawson, M.D., FAAP
  • Scott Iwashyna, M.D., FAAP

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Thumb-sucking & Nail-biting Children Show Fewer Allergies in Later Life


So sucking thumbs and nail biting is not bad....and actually has benefits! Read on...

Children between ages 5 and 11 whosucked their thumbs or bit their nailswere at a lower risk of developingallergies at a later age, although no association was found with asthma or hay fever, according to a study in the August 2016 Pediatrics. 

The study, “Thumb-Sucking, Nail-Biting, and Atopic Sensitization, Asthma, and Hay Fever,” published online July 11, suggests that childhood exposure to microbial organisms reduces the risk of developing allergies.

The Dunedin, New Zealand-based study followed 1,037 participants born in 1972-1973. Parents reported their children’s thumb-sucking and nail-biting habits when their children were ages 5, 7, 9, and 11 years old. They were checked at ages 13 and 32 years old for atopic sensitization, defined as a positive skin prick test to at least one common allergen. At age 13, the prevalence of sensitization was lower among children who had sucked their thumbs or bit their nails (38 percent) compared with those who did not (49 percent).

The associations were still present at age 32 years and persisted even with adjustments for confounding factors such as sex, parental history of allergies, pet ownership, breastfeeding and parental smoking.

While the report does not encourage that children take up these oral habits, the findings suggested that there is an apparent protective effect against allergies that persists into adulthood.