Wheezing can affect up to half of all children by age 3.
Recurrent wheezing in children with allergies is a risk factor for asthma. The indoor environment of poor urban areas can expose children to allergens that lead to recurrent wheezing.
Contrary to expectations, inner city children with high levels of exposure to microbes, cockroach, mouse, cat or dust mites, were less likely to wheeze by age of 3 years. In additon, households with high levels of bacteria were less likely to have allergies.
This once again leads credence to the hygiene hypothesis. High levels of bacteria at an early age can lead to less allergies in the future. Obviously you don’t want to expose your children to a lot of bacteria which would lead them to get sick more often. But we also should not prescribe antibiotics frequently and use antibiotic hand creams very frequently. Sometimes it may be okay to let your children play in dirt and in the sandbox.