Gastroesophageal Reflux Disease (GERD): The combination of postnasal drip, dry cough, occasional vomiting, and enlarged vocal cords, especially with a new onset of sore throat, suggests GERD as a primary cause. The stomach acid reflux can irritate the throat, leading to these symptoms.

Allergic Rhinitis: Postnasal drip and dry cough can be symptoms of allergic rhinitis, which could also contribute to a sore throat due to constant irritation from nasal secretions.
Laryngopharyngeal Reflux (LPR): Similar to GERD, LPR involves the reflux of stomach acid into the throat, which can cause sore throat, dry cough, and enlarged vocal cords.
Viral Pharyngitis: Although the sore throat is new, viral pharyngitis could be a cause, especially if the patient has been exposed to someone with a similar illness.

Laryngeal Cancer: Although rare, laryngeal cancer can present with a sore throat, dry cough, and enlarged vocal cords. It's crucial to rule out this diagnosis, especially in patients with risk factors like smoking.
Epiglottitis: This is a potentially life-threatening condition that can cause severe sore throat, difficulty swallowing, and shortness of breath. It requires immediate medical attention.
Angioedema: This condition can cause swelling of the throat and vocal cords, leading to a sore throat and potentially life-threatening airway obstruction.

Sarcoidosis: This autoimmune disease can affect various parts of the body, including the lungs and throat, leading to symptoms like dry cough and sore throat.
Relapsing Polychondritis: A rare autoimmune disorder that can cause inflammation of the cartilage in the throat, leading to sore throat and other respiratory symptoms.

GERD and LPR: Treatment typically involves proton pump inhibitors (PPIs) and lifestyle modifications. Diagnosis can be supported by symptom improvement with treatment, pH monitoring, or endoscopy.
Allergic Rhinitis: Diagnosis can be made based on history and physical examination, with treatment involving antihistamines, nasal corticosteroids, and avoidance of allergens.
Viral Pharyngitis: Diagnosis is often clinical, with treatment focused on symptom relief.
Laryngeal Cancer, Epiglottitis, Angioedema: These conditions require urgent evaluation, often involving imaging studies (CT or MRI), direct laryngoscopy, and potentially biopsy for diagnosis. Treatment varies widely depending on the condition.
Sarcoidosis and Relapsing Polychondritis: Diagnosis involves a combination of clinical presentation, imaging (chest X-ray or CT), and biopsy. Treatment typically involves corticosteroids and other immunosuppressive medications.