| Pathogen | Relative frequency* | Associated clinical syndrome and/or symptoms |
Bacteria | Group A Streptococcus | Common | Fever, tonsillar exudates, tender cervical lymphadenopathy, scarlatiniform rash, particularly in an adolescent or young adult |
Group C or G Streptococcus | Less common | Similar to GAS pharyngitis but more frequently acquired in a waterborne or foodborne outbreak |
Arcanobacterium haemolyticum | Less common | Similar to GAS pharyngitis, scarlatiniform rash common, particularly in adolescents and young adults |
Fusobacterium necrophorum | Uncertain | Lemierre syndrome (septic jugular vein thrombophlebitis), possible association with recurrent or persistent pharyngitis |
Neisseria gonorrhoeae | Likely rare | Nonspecific symptoms such as acute sore throat, pharyngeal exudates, and cervical lymphadenopathy in a patient with risk factors for sexually transmitted infections, particularly receptive oral intercourse |
Corynebacterium diptheriae | Rare | Diphtheria: Low-grade fever, anorexia, malaise, sore throat with gray-white membrane on palate, tonsil or posterior oropharynx, cervical lymphadenopathy, particularly in a patient who has not been vaccinated |
Mycoplasma pneumoniae | Rare | Cough, pneumonia |
Chlamydia pneumoniae | Rare | Fever, cough, laryngitis, pneumonia |
Treponema pallidum | Rare | Secondary syphilis: Sore throat may precede development of mucosal ulcers, generalized lymphadenopathy and palmar-plantar rash |
Francisella tularemia | Rare | Ulceroglandular fever: Severe sore throat, pharyngeal exudes, cervical lymphadenopathy (often posterior and bilateral), oral ulcers; usually acquired by ingestion of contaminated water |
Viruses | Respiratory viruses | Very common | Common cold: Fever, rhinorrhea, cough, hoarseness, coryza, conjunctivitis, oral ulcers |
Epstein-Barr virus | Less common | Infectious mononucleosis: Fever, fatigue, tender cervical lymphadenopathy, splenomegaly, lymphocytosis, particularly in an adolescent or young adult |
Herpes simplex virus | Less common | Severe sore throat, with or without oral ulcers |
Cytomegalovirus | Rare | Mononucleosis-like syndrome, similar to EBV but typically milder |
HIV | Rare | Acute retroviral syndrome: Fever, fatigue, lymphadenopathy, rash, myalgias, arthralgias, diarrhea, weight loss, painful mucocutaneous ulcers |