Researchers at the University of Cincinnati say owning a dog seemed to have some "immunotherapy" benefit and reduced other allergies, Britain's Daily Telegraph reported Thursday.
But allergic children with a cat in the house exhibited a dramatic increase in their sensitivity to reactions, the study found.
The study particularly examined the relationship between pet ownership and eczema.
The researchers found that children who tested positive for dog allergies were less likely to develop eczema by age 4 if they owned a dog before the age of 1.
But unlike dog ownership, cat ownership seemed to have a negative effect on children with cat allergies.
"Children who owned a cat before age 1 year and were allergic to cats based on a skin allergy test were 13 times more likely to develop eczema by age 4," Dr. Tolly Epstein said.
Parents of children at risk for eczema may want to consider the findings when choosing a family pet, she said.