Pharyngitis is a common presenting symptom of primary care medicine.  Pharyngitis can result from post nasal drip, gastroesophageal reflux, mechanical irritation, or tobacco abuse with infectious etiologies representing a common cause.  Over-treatment with antibiotics is to be discouraged in this era of antibiotic resistance.

     Viral etiologic agents are the most common cause, and since they are self-limited, require only symptomatic, temporary therapy mostly with anti-inflammatory or short-acting narcotic analgesics.  Of the bacterial causes, group A beta-hemoytic streptococci causes the most concern to the clinician.  The main reason to diagnose and treat GABH streptococci is to limit patient discomfort and, more importantly, to avoid the potential complications of this infection mainly rheumatic fever, scarlet fever, peritonsillar/retropharyngeal abscess, mastoiditis, sinusitis, or otitis media.  Poststreptococcal glomerulonephritis is another potential complication; however, there is no evidence that treatment of the pharyngitis prevents glomerular disease.  Other bacterial etiologies for pharyngitis include Arcanobacterium haemolyticum, Corynebacterium diptheriae, Neisseria gonorrhea, Mycoplasma pneumonia, and Chlamydia pneumonia.

     Diagnosis of GABH streptococcal pharyngitis should follow through several steps.  First, the clinician should determine the likelihood of this type of infection.  This is done by the physical exam and history, which are then applied to certain diagnostic criteria.  The Centor Criteria include the presence of tonsilar exudates, anterior cervical lymphadenopathy, fever, and the absence of cough or other symptoms of a viral infection (rhinitis, conjunctivitis, myalgias, etc).  If three or more of the criteria are present, then GABH streptococcal infection is possible; however, if three or more of the criteria are lacking, then further work-up is unnecessary.  If infection is deemed possible, then proceeding with throat swab for a rapid antigen-detection test and possible culture is the next step.  If the rapid antigen-detection test is positive, then treatment is indicated.  If the rapid antigen-detection test is negative but clinical suspicion remains high, then proceed with throat culture.  Treatment is with penicillin V or amoxicillin for ten days.

     The next most concerning etiologic agent is Epstein-Barr virus mononucleosis.  Common symptoms include sore throat, fever, diffuse lymphadenopathy, tonsilar exudates, petechiae of the palate and splenomegaly.  Clues to the diagnosis include the presence of greater than 50% lymphocytes with 10 % atypical lymphocytes or the presence of 20% atypical lymphocytosis on the white blood cell differential.  An ampicillin or amoxicillin induced rash is another characteristic feature of this disorder.  Diagnostic testing includes a positive monospot test; however, this test may remain negative during the first three weeks of infection so weekly repeat testing may be required during the first three weeks of symptoms.  A positive monospot test secures the diagnosis.  In cases where the monospot remains negative but the diagnosis is still suspected, further testing with IgM antibodies to viral capsid antigen may prove helpful.  Other etiologic agents to consider include cytomegalovirus (CMV), toxoplasmosis, rubella, and hepatitis A virus.  Therapy is mainly rest (avoid physical exertion/contact is recommended to lower the risk of splenic rupture during the first three to four weeks of infection) and analgesics.  When pharyngeal symptoms cause airway obstruction or anorexia, corticosteroids may provide symptomatic relief; however, their routine use is not encouraged for milder cases.

     Lemierre’s syndrome is an infection of the orophaynx with the possibility of septic emboli and thrombophlebitis of the internal jugular vein.  Fusobacterium necrophorum is the most common etiologic agent detected on blood cultures. CT scanning of the neck will reveal the thrombosed vein. Ludwig's angina is a cellulitis of the submandibular space bilaterally which manifests as neck and submandibular swelling/edema/erythema, fever, trismus, inability to swallow (even saliva), enlargement of the tongue, and pain. Potential complications include the spread of infection to the mediastinum, pharyngomaxillary spaces or bone, and airway obstruction. This is often a polymicrobial infection due to Streptococcus species, Staphylococcus species, Fusobacterium, and/or Bacteroides species. Immunocompromised patients are subject to infection with Pseudomonas, Escherichia coli, Candida, or Clostridium.  Blood cultures help determine the etiologic agent, and CT or MRI may reveal the extent of the infected area. Treatment includes airway monitoring/protection, maxillofacial or otolaryngology consultation for possible debridement, and broad spectrum antibiotics covering gram-positive, gram-negative, and anaerobic bacteria.