You have been trying to figure out what is wrong with you. You have been using a lot of Kleenexes and multiple over-the-counter medications, and yet you are still stuck with a stuffy nose.
A stuffy nose is always a bummer since it causes discomfort. It only affects your nose, and yet you feel like your whole day will be affected because of it. A stuffy or a congested nose happens because the tissues lining the nose are swollen. Inflamed blood vessels causes this swelling. 
So what causes stuffy nose? And when should you see a doctor if you have it?
Our bodies have a natural inflammatory response to foreign objects, and that response is the cause of allergies. Examples of foreign objects that may cause allergies are pollen, pet hair and dust.
This is because when the allergens get to our nose, eyes, mouth and ears, our body releases histamines in response as an allergic reaction and causes symptoms such as stuffy nose and runny eyes. 
2. Noncancerous growths called nasal polyps
Nasal polyps are a type of benign sinonasal tumor. Depending on where the benign tumour is located, it may cause nasal obstruction.
Nasal polyps can grow anywhere on the lining of the nose or the sinuses. If they are small polyps, it may not cause any problems. However, large polyps can block your sinuses or nasal airway. 
3. Sinus infection
Acute sinus infections produce pain, nasal congestion and thick discharge. Chronic sinus infections usually involve nasal obstruction and offensive nasal or postnasal discharge may or may not cause pain.
When the nasal mucus turns to yellow or green, it usually means that there is a bacterial infection and you should go see a doctor.
4. Hay fever
Hay fever is also known as allergic rhinitis. It is like allergies, where our bodies react to foreign bodies in the environment. Some of the symptoms of hay fever are stuffy nose due to blockage or congestion, runny nose, itchy eyes, mouth or skin, sneezing and fatigue.
Allergic rhinitis has two types, seasonal and perennial. The seasons of spring, summer and early fall are when seasonal allergic rhinitis typically happens because of airborne mold spores or pollens from grass, trees and weeds which our bodies may react to.
Perennial allergic rhinitis experience happens all throughout the year. Dust mites, pet hair or dander, cockroaches or mold are the main causes. 
5. Nasal septum deviation
Our nostrils are separated by a cartilage and a bone, which is called the nasal septum. If it is crooked or off-center due to a congenital defect or trauma to the nose, it can interfere with normal airflow and problems.
Some of the symptoms of a deviated septum include a stuffy nose, snoring, recurring bacterial infections, and frequent or chronic postnasal drip. 
When to see a doctor
- You have been experiencing congestion for more than 10 days.
- You have been experiencing both congestion and a high fever for more than three days.
- Your nasal mucus turns to yellow or green. This usually means that a bacterial infection is going on.
- You have a weakened immune system, asthma, or emphysema.
Do not delay going to the doctor if you have the symptoms above. Do not wait until your condition gets worse or complicated before getting yourself checked. With any condition or symptom that you feel is not normal, the safest thing to do is to seek help from a professional.