My son has been coughing in the middle of the night for 2 weeks now. I thought he was sick but when we took him to the peds, she said it looked like it was allergy-related. We washed all of his sheets and blankets and covered his mattress. But he's still coughing. She suggested using an air purifier in his room so we're researching right now.

Do any of you use an air purifier in your LO's room? If so, any recommendations on which type to get?