Pharyngitis natural history, complications and prognosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Aysha Anwar, M.B.B.S[2], Venkata Sivakrishna Kumar Pulivarthi M.B.B.S [3]

The sore throat, fever, and malaise associated with acute pharyngitis are distressing, but with few exceptions, these illnesses are both benign and self-limited. Many bacterial and viral organisms are capable of inducing pharyngitis, either as a single manifestation or as part of a more generalized illness. History and symptoms are essential to diagnosis to identify the treatable causes (e.g., GAS) to prevent complications.

• Acute pharyngitis is typically described as the triad of sore throat, fever, and pharyngeal inflammation characterized by erythema and edema, although exudates, vesicles, or ulcerations may also be present.
• Although pharyngitis may be a primary disorder, sore throat and pharyngeal erythema may also be prominent in systemic disorders, such as acute retroviral syndrome, or part of a more generalized upper respiratory tract infection.
• Most cases of acute pharyngitis are due to common viral infections and are benign,self-limited processes.^[1]
• The appropriate recognition of patients with more complicated infections that require diagnostic evaluations and treatment is one of the challenges of primary care medicine.^[2] An estimated 1-2% of acute pharyngitis progresses to recurrent or chronic disease.^[3]
• Patients with recurrent episodes of pharyngitis and more than one episode of streptococcal pharyngitis at close intervals associated with laboratory evidence of GAS pharyngitis consider that they should also be alert to the possibility that the patient may actually be a chronic pharyngeal GAS carrier who is experiencing repeated viral infections.^[4]

• Strep pharyngitis occurs predominantly, though not exclusively, in school-age children.^[1]
• Symptoms develop after a short incubation period of 24 to 72 hours.^[5]
• Symptoms can vary widely, with some patients experiencing the full effects of the syndrome while others, such as those who have undergone tonsillectomy, may have milder symptoms.^[1]
• Untreated, group A beta-hemolytic streptococcus (GABHS) infection lasts 7-10 days. Patients with untreated streptococcal pharyngitis are infectious during the acute phase of the illness and for one additional week.
• Effective antibiotic therapy shortens the infectious period to 24 hours, reduces the duration of symptoms by about one day, and prevents most complications.^[5]

• The incubation period of Corynebacterium diphtheriae infection range between 2-4 weeks.^[5]
• Diphtheria common in children and primarily among unimmunized or poorly immunized members of socioeconomically disadvantaged groups.^[1]

Identifying the cause of pharyngitis, especially GABHS, is important to prevent potential life-threatening complications.☃☃ Serious complications of pharyngitis may include peritonsillar abscess or retropharyngeal abscess.☃☃ Complications of pharyngitis based on the causing agent include the following: ^[6]

Rheumatic fever is exceedingly rare in the United States and other developed countries (annual incidence of less than one case per 100,000). This illness should be suspected in any patient with joint swelling and pain, subcutaneous nodules, erythema marginatum or heart murmur, and a confirmed streptococcal infection during the preceding month. Patients will have an elevated antistreptolysin- O titer and erythrocyte sedimentation rate.^[5]

Post streptococcal glomerulonephritis is another rare complication of GABHS pharyngitis, although treatment with antibiotics does not prevent it. Patients present with hematuria and, frequently, edema in the setting of a recent streptococcal infection with an elevated antistreptolysin-O titer.^[5]

Scarlet fever is another complication of GABHS pharyngitis and usually presents as a rash characterized by punctate, erythematous, branch able, sandpaper-like exanthematous rash. Rash distributes in the neck, groin, and axillae, and accentuate specifically in the body folds and creases. Other findings include pharynx and tonsils appear erythematous and covered with exudates and tongue appears as bright red with white coating, also known as strawberry tongue.

Most cases of pharyngitis go away on their own without complications.