Wairarapa asthma sufferers are also using more medications each year, with prescription numbers rising from 15,389 to 17,284 between 2008 and 2012.
The allergens study, published in the online Journal of Asthma, analysed dust collected from 40 children's soft toys and mattresses and found 35 had detectable cat and 34 had detectable dog allergen levels.
While all mattresses and soft toys had detectable house dust mite allergen levels, soft toys contained about three times the level of those on mattresses.
Study researcher associate professor Rob Siebers said exposure to allergens on toys tended to be greater than exposure to mattresses, because of the proximity to children's airways. While soft toys had long been recognised as a source of house dust mite allergens, this was the first major study to confirm they were also a source of cat and dog allergens, regardless of whether the home had pets, he said.
"Cat and dog allergens are aerodynamic and can be transported on clothing into animal-free areas, even in cat-free areas such as the Antarctic."
He recommended regular cold washes in the washing machine, which was proven to get rid of cat and dog allergens.
"My advice to parents, particularly of children who are sensitised asthmatics, is to put the toy their child sleeps with through the wash at least weekly."
New Zealand Asthma Foundation medical advisor Dr Tristram Ingham agreed with the study's results, and recommended giving toys a good wash or replacing them for Christmas.
APNZ
