My nose keeps running nonstop indoors during winter and I am not sick at all. What is causing this?

7. Hidden Allergies: Mold, Pet Dander, And Dust Mites That Flare Up In Winter
Allergens such as mold spores, pet dander, and dust mites can become more concentrated indoors during winter. With windows and doors closed to keep out the cold, these allergens can accumulate, triggering allergic reactions in sensitive individuals. Unlike seasonal allergies caused by pollen, these indoor allergens can lead to symptoms like a runny nose throughout the winter months.
Regular cleaning, using HEPA filters, and maintaining good ventilation can help manage these allergens and reduce their impact on your nasal health.