House dust mite allergy is like this. It's dust mite poop in bedding. Zip cases on mattress, pillows, duvet. Wash weekly at 60c.My son, now 9, suffers from sneezing, runny, stuffy nose every morning and it tends to disappear into the afternoon.
Yes, I wondered about that.You can develop allergies later in life. You mention that it can't be the dog, but then you say he goes everywhere with you... What are you like when you are away from him?