Dogs may lower risk of childhood eczema, reduce asthma symptoms

Dogs are commonly hailed as "man's best friend," and two new studies emphasize why this title is so well deserved. Scientists have revealed that exposure to dogs during early life may protect against eczema and reduce asthma symptoms in childhood.

Perhaps unsurprisingly, dogs are the top choice when it comes to household pets in the United States; almost 54.4 million U.S. households own at least one canine companion.

That wagging tail and fun, loyal nature may be reason enough to love your four-legged friend, but science shows that there are many other reasons to cherish your dog.

One study reported by Medical News Today earlier this year, for example, found that children in households with a dog had lower stress levels, while other research has shown that having a dog can boost owners' physical activity levels.

Research has also linked pet ownership to a lower risk of allergies and asthma, particularly among children. Two new studies build on such research, after finding that exposure to dogs in early life could help to stave off childhood eczema and ease asthma symptoms.

The results of the studies were recently presented at the American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting, held in Boston, MA.

Prenatal dog exposure reduces eczema risk

The first study was led by ACAAI member Dr. Gagandeep Cheema, and it investigated how exposure to dogs before birth influenced the risk of childhood eczema.

Eczema, or atopic dermatitis, is a condition characterized by rashes and patches of dry, itchy skin, most commonly on the hands, feet, and face, as well as on the insides of the elbows and behind the knees.

The exact causes of eczema remain unclear, but there is a consensus that the condition may arise when the immune system overreacts in response to certain allergens or irritants.

For their study, Dr. Cheema and her team assessed the dog exposure of a number of expectant mothers. For the purpose of the study, dog exposure was defined as keeping at least one dog inside the house for at least 1 hour every day.

They found that children born to mothers who were exposed to dogs during pregnancy were less likely to develop eczema by the age of 2 years, compared with children born to mothers who were not exposed to dogs.

However, the study revealed that by the time children reached the age of 10 years, the protective effects of prenatal dog exposure declined.

Dog bacteria vs. allergens

In the second study, lead author Dr. Po-Yang Tsou — who is also a member of the ACAAI — and team investigated how dog exposure affected asthma severity in children with the condition.

The team evaluated the effects of two types of dog exposure: exposure to the protein that triggers an allergic reaction in children with dog allergy, and exposure to certain particles — such as bacteria — that a dog might carry.

The researchers found that children who were exposed to bacteria and other particles from a dog experienced a reduction in asthma symptoms.

However, exposure to the dog protein appeared to exacerbate symptoms of the respiratory condition.

"There seems to be a protective effect on asthma of non-allergen dog-associated exposures, and a harmful effect of allergen exposure," notes Dr. Tsou, who stresses that exposure to dog allergens remains a "major concern" for children who have a dog allergy.

Further studies are needed to confirm whether or not exposure to dogs before and after birth can help to protect against eczema and asthma in childhood. But in the meantime, keep in mind that your four-legged friend could one day help to transform the outlook for childhood allergies.