Differential Diagnoses for Strep Pharyngitis

When considering the differential diagnoses for strep pharyngitis, it's crucial to categorize them based on their likelihood and potential impact on patient health. Here's a structured approach:

• Single Most Likely Diagnosis

  • Viral pharyngitis: This is the most common cause of pharyngitis and can be due to various viruses such as adenovirus, influenza, and rhinovirus. The symptoms can be very similar to those of strep pharyngitis, making it a key differential diagnosis.

• Other Likely Diagnoses

  • Infectious mononucleosis (mono): Caused by Epstein-Barr virus (EBV), it can present with sore throat, fever, and lymphadenopathy, similar to strep pharyngitis.
  • Acute tonsillitis: Can be caused by both viral and bacterial pathogens, and the clinical presentation may overlap with that of strep pharyngitis.

• Do Not Miss Diagnoses

  • Lemierre's syndrome: A rare but potentially life-threatening condition that starts with pharyngitis and can progress to septicemia and thrombophlebitis of the internal jugular vein. It's caused by Fusobacterium necrophorum.
  • Peritonsillar abscess: A complication of tonsillitis that can lead to severe pain, difficulty swallowing, and potentially life-threatening airway obstruction if not promptly treated.
  • Diphtheria: Although rare in areas with high vaccination coverage, diphtheria is a bacterial infection that can cause severe pharyngitis and is potentially deadly if not treated.

• Rare Diagnoses

  • Gonococcal pharyngitis: Caused by Neisseria gonorrhoeae, it's more common in sexually active individuals and can present with symptoms similar to strep pharyngitis.
  • Tuberculous pharyngitis: A rare form of tuberculosis that affects the pharynx, more common in immunocompromised individuals or those from areas with high TB prevalence.
  • Syphilitic pharyngitis: Caused by Treponema pallidum, it's a rare condition that can occur in the primary stage of syphilis and presents with a painless sore throat.