Allergic Rhinitis: This is the most common cause of turbinate congestion, often triggered by allergens such as pollen, dust mites, or pet dander, leading to inflammation and swelling of the nasal turbinates.

Viral Upper Respiratory Infection (URTI): Common colds and other viral infections can cause turbinate congestion due to increased blood flow and swelling in response to the infection.
Non-Allergic Rhinitis: This includes a variety of conditions that cause chronic nasal congestion without an identifiable allergy, such as vasomotor rhinitis, where the nasal blood vessels are overly sensitive.
Anatomical Issues: Deviated septum, nasal polyps, or enlarged adenoids can physically obstruct airflow, leading to turbinate congestion.
Environmental Irritants: Exposure to tobacco smoke, strong odors, or air pollution can irritate the nasal passages and cause congestion.

Nasal Tumors: Although rare, tumors such as squamous cell carcinoma or adenocarcinoma can cause unilateral nasal obstruction and turbinate congestion.
Invasive Fungal Sinusitis: A serious condition, especially in immunocompromised patients, which can lead to significant morbidity and mortality if not promptly treated.
Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A systemic vasculitis that can affect the nasal passages and sinuses, leading to destruction of the nasal tissue.

Sarcoidosis: A systemic disease that can cause granulomatous inflammation in the nasal passages, leading to congestion and other symptoms.
Eosinophilic Granuloma with Polyangiitis (Churg-Strauss Syndrome): A rare autoimmune condition that can affect the nasal passages and cause congestion among other systemic symptoms.
Primary Ciliary Dyskinesia (Kartagener Syndrome): A genetic disorder affecting the cilia in the respiratory tract, leading to chronic sinusitis and nasal congestion.