Differential Diagnosis for a 21-year-old woman with erythema and swelling of the posterior pharynx, medial deviation of the soft palate, and peritonsillar fold

• Single most likely diagnosis:
  • Peritonsillar abscess: This condition is characterized by a collection of pus behind the tonsils, which can cause swelling and erythema of the posterior pharynx, medial deviation of the soft palate, and peritonsillar fold. The symptoms presented are classic for this diagnosis.
• Other Likely diagnoses:
  • Tonsillitis: Inflammation of the tonsils can cause similar symptoms, including erythema and swelling of the posterior pharynx and peritonsillar area.
  • Pharyngitis: Infection or inflammation of the pharynx can lead to symptoms such as erythema and swelling of the posterior pharynx.
  • Retropharyngeal abscess: Although less common, an abscess in the retropharyngeal space can cause similar symptoms, including medial deviation of the soft palate.
• Do Not Miss diagnoses:
  • Epiglottitis: This is a life-threatening condition that requires immediate attention. Although the symptoms presented do not directly point to epiglottitis, any condition causing significant airway compromise needs to be considered.
  • Lemierre's syndrome: A rare but serious condition characterized by a bacterial infection of the tonsils and the formation of a thrombus in the internal jugular vein. It can present with symptoms similar to those described.
• Rare diagnoses:
  • Parapharyngeal space infection: Infections in this space can cause swelling and erythema of the posterior pharynx and medial deviation of the soft palate, but they are less common.
  • Nasopharyngeal carcinoma: Although rare, especially in young adults, it can cause symptoms such as swelling and erythema of the posterior pharynx due to tumor growth.
  • Granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis): A rare autoimmune disorder that can cause a wide range of symptoms, including those affecting the respiratory tract, but it would be an unusual cause of the specific symptoms described.