A blocked nose can result from several common causes, including infections, allergies, structural issues, and environmental factors.

1. Common Causes of Blocked Nose

   • Viral infections like the common cold or flu often cause nasal congestion due to inflammation and mucus buildup.
   • Allergies to pollen, dust, or pet dander can trigger nasal swelling and blockage.

2. Infections

   • Sinusitis, a bacterial or viral infection of the sinuses, can cause persistent nasal blockage accompanied by facial pain or pressure.

3. Allergic Reactions

   • Exposure to allergens leads to inflammation of nasal passages, causing stuffiness and sneezing.

4. Structural Issues

   • Conditions such as nasal polyps or a deviated septum can cause chronic nasal obstruction that does not improve with typical treatments.

5. Environmental and Lifestyle Factors

   • Irritants like smoke, pollution, or dry air can inflame nasal tissues, worsening congestion.

6. When to Seek Medical Advice

   • If nasal blockage lasts more than 10 days, is accompanied by severe pain, bleeding, or fever, or if over-the-counter treatments do not help, consult an ear, nose, and throat (ENT) specialist.

7. Relevant Medical Specialties and Diagnostic Tests

   • An ENT specialist can evaluate persistent nasal blockage and may use nasal endoscopy or allergy testing to identify the cause.

If you want, I can explain how nasal sprays like xylometazoline work to relieve congestion. Meanwhile, please consider seeing an ENT doctor for a thorough evaluation and appropriate treatment.