Pets are a cause of allergy, half of all asthmatic children allergic to cats and 40% allergic to dogs. When animals cleaning themselves by to lick, skin cells covered in saliva, and then animal shed dander with fur. From a large Swedish study that has latest found, suggest exposure with dog dander in infancy may be beneficial. Children who had grown up with a dog were less likely to have asthma than children without dogs. Exposure to a dog since infancy has 13% to lower risk of asthma in later childhood. The findings, in JAMA Pediatrics, support the idea that pets can boosting the immune system and prevent allergy. Living on a farm with lots of animals seemed to reduce the risk of asthma by about 50% which is consistent with the hygiene hypothesis that exposure to dust and dirt to improve our tolerance of common allergens. The parent should not worry about getting a dog or a puppy. But if you have an allergic child you should not get a dog to cure your child. It will probably make the allergy worse.