According to new study in the U.S. children who are exposed to cats soon after birth may have an increased risk of developing eczema, while being exposed to two or more dogs at home may offer some slight protection.
Lead researcher Esmeralda Morales, M.D., Pediatric Pulmonary Fellow at the University of Arizona in Tucson, says other studies have found that having cats or dogs at home appears to protect against allergic diseases, so they expected to have similar findings.
Apparently pets are a source of a compound called endotoxin, and if a child is exposed to endotoxin early in life, the immune system may be skewed away from developing an allergic profile.
The study which tracked 486 children from birth, asked parents how many cats and dogs they had in the house at the time the child was born, and then followed up one year later to see which children had been diagnosed with eczema.
It was found that of the 134 children with cats in the household, 27.6% had eczema by one year of age, compared with 17.8% of 286 children without cats.
That equates to more than a quarter of babies in cat households with eczema by age 1, compared with one in six of children living without cats.
While exposure to cats increased a child's risk of eczema whether or not their mother had asthma, the effect was more pronounced in children whose mothers did not have asthma.
Asthma could be a possible marker of mothers less likely to encourage cat contact.
Previous studies have found that people with eczema have a higher chance of also having allergic conditions including hay fever and asthma.
Dr. Morales says that the children in the study who developed eczema at age 1 might possibly end up having a reduced risk of asthma or other allergic diseases later in life, but she believes the findings raise more questions about pets and asthma and allergies.
Morales says much of the data already documented is contradictory and there is clearly a need for further research.
Experts in the field say that while the study was interesting, it is too early to draw firm conclusions as there are many questions about the risk of exposure to pets and atopic diseases such as eczema, and caution needs to be exercised before advising that pets should be removed from the home environment.
Some scientists believe that unless the immune system is exposed to adequate challenges in childhood it fails to develop properly.