Non-allergic rhinitis is a condition that causes nasal symptoms such as congestion, runny nose, and sneezing, but it is not triggered by allergens like pollen or pet dander. Instead, it can be caused by irritants such as smoke, strong odors, or changes in weather. This condition can affect people of all ages and is often mistaken for allergies. Unlike allergic rhinitis, which involves the immune system reacting to allergens, non-allergic rhinitis does not involve an immune response. Treatment may include avoiding triggers, using saline nasal sprays, or taking medications like decongestants to relieve symptoms.