Research highlights the protective role of pet ownership in preventing eczema in children without FLG mutations.

Growing up with stories of The Famous Five, I’d yearned for a pet for as long as I can remember. When the day finally arrived, it wasn’t the Timmy-esque dog of my dreams, but a Syrian hamster which I named Honey. Honey was a wonderful pet, gentle and confident, and I poured my love into him until he died of old age. I distinctly remember my father burying him in the corner of our garden, with an Ikea candle standing vigil to light his way onwards.

Pets can be beneficial for children for a number of reasons, including providing strong social and emotional support which can boost self-esteem and reduce feelings of loneliness. However, there is some evidence that early exposure to pets can impact a child’s risk of developing allergies later in life. For this reason, a recent birth cohort study conducted in Tokyo, Japan, investigated the link between growing up with pets and the development of early childhood eczema.

Eczema in children

Allergies are on the rise worldwide, including in children, and are now recognised as a global health issue by the World Health Organisation. Therefore, developing a comprehensive understanding of the contributing factors to conditions such as eczema is crucial. Eczema is a chronic skin condition, affecting at least 1 in 5 children in the UK, which causes patches of itchy, red, dry and cracked skin.

Eczema is thought to be highly hereditary with some genetic mutations being established as contributing factors, such as FLG mutations. The FLG gene supports the production of filaggrin which contributes to the skin barrier function, but loses this ability when mutated. However, the development of eczema is also believed to be impacted by a person’s environment, including the presence of pets, which was investigated in the recent study.

Research into pet ownership

The birth cohort study conducted in Tokyo, Japan, included 1,701 pregnant women and resulted in 1550 newborn babies. The mothers answered questionnaires during the follow-up period when the children were 6, 12 and 18 months of age, and yearly between the ages of 2-5. Pet ownership was confirmed by the question, “Do you keep dogs/cats indoors at home?”

The results revealed that household dog and dog+cat ownership, but not cat ownership alone, reduced the risk of childhood eczema, which is consistent with findings from a previous systematic review of the literature. However, this reduction in risk was only observed in children without mutations in their FLG gene, suggesting that the benefits of pet ownership are reduced by FLG loss-of-function mutations.

How pets protect against eczema

Although the protective mechanism is not fully understood, it has been suggested that the presence of pets in the home increases the diversity of the microbial environment. Being exposed to an expansive range of microorganisms is thought to play an important role in regulating a child’s immune system, reducing the risk of developing allergies. Although, the effect was not observed in children with FLG mutations, suggesting that they override the potential preventative effect of pets.

This theory, along with the findings of this study, are supported by previous research which observed that dogs, but not cats, increased the diversity of dust in the home. However, eczema development could also be impacted by the different dominant microbial species in dogs and cats, or the manner in which they are housed, with cats being kept indoors, but dogs being walked outdoors.

Study implications

The study’s findings offer valuable insights into the potential protective effects of pet ownership against eczema for children without FLG mutations. They suggest that families considering adding a pet, especially a dog, to their lives might enjoy more than the love and laughter that a pet can bring, especially for families with a history of eczema.

The study highlights the important interplay between genetic and environmental factors in understanding the development and management of allergies in childhood. However, caution should be taken when interpreting the study’s findings outside of Japan. For example, cats in the UK are often permitted outdoor access which could mean that they introduce different or more microbial diversity into the home.

Key study findings:

• Dog ownership associated with lower eczema risk
• No protective effect observed for cat ownership
• No protective effect observed for children with FLG mutations