Acute Epiglottitis: This condition is characterized by inflammation of the epiglottis, which can cause sudden onset dysphagia (difficulty swallowing) and swelling in the neck. It's a medical emergency that requires prompt attention.

Peritonsillar Abscess: An abscess near the tonsils can cause severe throat pain, difficulty swallowing, and swelling in the neck. It's a common complication of tonsillitis.
Deep Neck Infection: Infections in the deep spaces of the neck can lead to swelling, pain, and difficulty swallowing. These infections can be life-threatening if not treated promptly.
Esophageal Foreign Body: An object lodged in the esophagus can cause sudden dysphagia and may lead to swelling in the neck if it causes an infection or abscess.

Ludwig's Angina: A severe infection of the tissues in the neck, which can cause difficulty swallowing, neck swelling, and potentially life-threatening airway obstruction.
Retropharyngeal Abscess: An abscess in the tissues at the back of the throat can cause dysphagia, neck swelling, and is a medical emergency due to the risk of airway compromise.
Thyroid Storm: A life-threatening complication of untreated or undertreated hyperthyroidism, which can present with neck swelling (due to goiter), difficulty swallowing, and other systemic symptoms.

Eosinophilic Esophagitis: A chronic inflammatory condition of the esophagus that can cause dysphagia, but it typically has a more gradual onset.
Cervical Esophageal Web: A rare condition where a membrane or web forms in the esophagus, causing dysphagia. It might not directly cause neck swelling but could be considered in the differential for dysphagia.
Neck Hematoma: Bleeding into the tissues of the neck can cause swelling and potentially dysphagia if it compresses the esophagus or airway. This could be due to trauma, anticoagulation, or a bleeding disorder.