I always sneeze in the morning, is it allergy?

No: You may have an allergy if you notice it doesn't happen in a different house or in a hotel. But our hormones and inflammatory substances in the blood can rapidly increase production and activity with the stress of waking up leading to things like sneezing. It all depends on whether you have other symptoms.

AM Sneezing: Hello, sneezing is a symptom commonly linked to allergy. Other forms of rhinitis do exist which are not allergy linked. Each of these conditions also are linked to sneezing. With that being said, the most likely cause would be allergy. I would suspect perennial or year round allergy such as dust mites, house dust or pet dander. Allergy testing may be helpful or try an otc antihistamine.