Pharyngitis Differential Diagnosis

The differential diagnosis for pharyngitis can be organized into several categories based on the likelihood and potential impact of each condition.

• Single Most Likely Diagnosis

  • Viral pharyngitis: This is the most common cause of pharyngitis, often resulting from infections such as the common cold or flu. The justification for this being the single most likely diagnosis is its high prevalence and the fact that most cases of pharyngitis are viral in nature.

• Other Likely Diagnoses

  • Streptococcal pharyngitis (Strep throat): Caused by Group A beta-hemolytic streptococcus, this condition is a common bacterial cause of pharyngitis and requires antibiotic treatment to prevent complications.
  • Infectious mononucleosis: Caused by Epstein-Barr virus, this condition can present with pharyngitis, fever, and lymphadenopathy, especially in young adults.
  • Acute tonsillitis: Inflammation of the tonsils, which can be caused by viral or bacterial infections.

• Do Not Miss Diagnoses

  • Epiglottitis: A potentially life-threatening condition that requires immediate medical attention. It involves inflammation of the epiglottis and can lead to airway obstruction.
  • Retropharyngeal abscess: A serious condition involving a collection of pus in the tissues at the back of the throat, which can also lead to airway obstruction and requires prompt treatment.
  • Lemierre's syndrome: A rare but serious condition characterized by a bacterial infection of the throat, followed by the spread of the infection to the bloodstream and internal organs, often with significant morbidity and mortality if not recognized and treated early.

• Rare Diagnoses

  • Diphtheria: A bacterial infection affecting the throat and upper respiratory tract, which is now rare in areas with widespread vaccination but can still occur, especially in unvaccinated individuals.
  • Gonococcal pharyngitis: Caused by Neisseria gonorrhoeae, this condition is a rare cause of pharyngitis but is significant due to its implications for sexual health and the potential for antibiotic resistance.
  • Tuberculous pharyngitis: A rare form of tuberculosis that affects the pharynx, more commonly seen in immunocompromised individuals or in areas with high prevalence of tuberculosis.