A 27-year-old woman complains of 2 days of sore throat, fever, and chills. She is unable to swallow anything other than liquids because of severe odynophagia. She denies any congestion or cough. On examination, she has bilateral tonsillar erythema and exudate (Figure 37-1). Her anterior cervical lymph nodes are tender. Based on the presence of fever, absence of cough, tender lymphadenopathy, and tonsillar exudate, you believe that she has a high probability of group A β-hemolytic Streptococcus (GABHS) pharyngitis. A rapid antigen detection test confirms the diagnosis, and you prescribe antibiotics.
Strep pharyngitis showing tonsillar exudate and erythema. (Reproduced with permission from Richard P. Usatine, MD.)
Pharyngitis is inflammation of the pharyngeal tissues and is usually associated with pain. The complaint of "sore throat" is a common one in the primary care office and can be accompanied by other symptoms and signs including throat scratchiness, fever, headache, malaise, rash, joint and muscle pains, and swollen lymph nodes.
Pharyngitis accounts for 1% of primary care visits.1
Viral infections account for an estimated 60% to 90% of cases of pharyngitis.
In patients ages 16–20 years, 1 in 13 presenting with sore throat have mononucleosis.2
Bacterial infections are responsible for between 5% and 30% of pharyngitis cases, depending on the age of the population (higher rates among children ages 4–7 years) and season (highest in winter).
The GABHS accounts for 5% to 15% of pharyngitis in adults and 20% to 30% in children.3 Up to 38% of cases of tonsillitis are because of GABHS.
Acute rheumatic fever is currently rare in the United States.
Up to 14% of deep neck infections result from pharyngitis.4
ETIOLOGY AND PATHOPHYSIOLOGY
Some viruses, such as adenovirus, cause inflammation of the pharyngeal mucosa by direct invasion of the mucosa or secondary to suprapharyngeal secretions.5 Other viruses, such as rhinovirus, cause pain through stimulation of pain nerve endings by mediators, such as bradykinin.
The GABHS releases exotoxins and proteases. Erythrogenic exotoxins are responsible for the development of the scarlatiniform exanthem (Figure 37-2).6 Secondary antibody formation because of cross-reactivity with the M protein (a virulence factor located peripherally on the cell wall) may result in rheumatic fever and valvular heart disease.6 Antigen–antibody complexes may lead to acute poststreptococcal glomerulonephritis.
Untreated GABHS pharyngitis can result in suppurative complications including bacteremia, otitis media, meningitis, mastoiditis, cervical lymphadenitis, endocarditis, pneumonia, or peritonsillar abscess formation (Figure 37-3). Nonsuppurative complications include rheumatic fever and poststreptococcal glomerulonephritis.
Scarlatiniform rash in scarlet fever. This 7-year-old boy has a typical sandpaper rash with his strep throat and fever. The erythema is particularly concentrated in the axillary area. (Reproduced with permission from Richard P. Usatine, MD.)
A. Peritonsillar abscess on the right showing uvular deviation away from the side with the abscess. (Reproduced with permission from James Heilman, MD.) B. Peritonsillar abscess with swelling and anatomic distortion of the right tonsillar region. (Reproduced with permission from Charlie Goldberg, MD, and The Regents of the University of California.)
GABHS: children aged 5 to 15 years, exposure to GABHS, presentation in winter or early spring.
Chronic irritation (e.g., allergies, cigarette smoking).
Rhinorrhea, cough, oral ulcers, and/or hoarseness are more consistent with a viral etiology.3 Rigors, cough, and epidemic make influenza more likely. Posterior cervical, inguinal or axillary adenopathy; palatine petechiae; and splenomegaly make mononucleosis more likely,2 as does fatigue.
Rapid-onset odynophagia, tonsillar exudates, anterior cervical lymphadenopathy, and fever are consistent with streptococcal pharyngitis.
Not all tonsillar exudates are caused by streptococcal pharyngitis. Mononucleosis and other viral pharyngitis can cause tonsillar exudates (Figures 37-4 and 37-5). The positive predictive value for tonsillar exudate in strep throat is only 31%; that is, 69% of patients with tonsillar exudate will have a non-streptococcal cause.
Para- and supratonsillar edema with medial and/or anterior displacement of the involved tonsil and uvular displacement to the contralateral side suggest peritonsillar abscess (see Figure 37-3). Trismus and anterior cervical lymphadenopathy with severe tenderness to palpation are additional findings.
Palatal petechiae can be seen in all types of pharyngitis (Figure 37-6).
A sandpaper rash is suggestive of scarlet fever (see Figure 37-2, and Chapter 36, Scarlet Fever and Strawberry Tongue).
Lymphoid hyperplasia can cause a cobblestone pattern on the posterior pharynx or palate from viral infections, gastroesophageal reflux disease (GERD), or allergies (Figure 37-7). Although it usually is more suggestive of a viral infection or allergic rhinitis, lymphoid hyperplasia can be seen in strep pharyngitis (Figure 37-8).
The following criteria are helpful in the diagnosis of GABHS pharyngitis7:
Fever or temperature of 38°C (100.4°F) (1 point)
Absence of cough (1 point)
Tender anterior cervical lymph nodes (1 point)
Tonsillar swelling or exudates (1 point)
<5 years (1 point)
5 to 15 years (0 points)
>15 years (-1 point)
Mononucleosis in a young adult with considerable tonsillar exudate. (Reproduced with permission from Richard P. Usatine, MD.)
Viral pharyngitis in a young adult showing enlarged cryptic tonsils with some erythema and exudate. (Reproduced with permission from Richard P. Usatine, MD.)
Viral pharyngitis with visible palatal petechiae. Palatal petechiae can be seen in all types of pharyngitis. (Reproduced with permission from Richard P. Usatine, MD.)
Viral pharyngitis with prominent vascular injection of the soft palate and lymphoid hyperplasia. (Reproduced with permission from Richard P. Usatine, MD.)
Strep pharyngitis with dark necrotic area on right tonsil and prominent lymphoid hyperplasia in a cobblestone pattern on the posterior pharynx. (Reproduced with permission from Richard P. Usatine, MD.)
The probability of GABHS is approximately 12% with <2 points, 29% with 2 or 3 points, and approximately 55% with 4 to 5 points.7
LABORATORY TESTS AND IMAGING
Rapid antigen detection testing (RADT) can be used to diagnose GABHS. Authors of a Cochrane review found a sensitivity of 85.6% and specificity of 95.4% in children.8 The authors concluded, based on these results, that of 100 children with strep throat, 86 would be correctly detected with the rapid test while 14 would be missed and not receive antibiotic treatment. Conversely, among 100 children with non-streptococcal sore throat, 95 would be correctly classified with the rapid test while 5 would be misdiagnosed as having strep throat.
The Infectious Disease Society of America (IDSA) recommends RADT for all patients with pharyngitis except for children under age 3 years or when sore throat is accompanied by overt viral features as above.9 The Centers for Disease Control and Prevention/American College of Physicians also support testing using RADT or culture in adult patients with symptoms suggestive of group A streptococcal pharyngitis.10
The gold standard for the diagnosis of streptococcal infection is a positive throat culture. However, GABHS is part of the normal oropharyngeal flora in many patients, and the definitive diagnosis of acute streptococcal pharyngitis must include both the clinical signs of acute infection and a positive throat culture.
Throat culture is recommended by IDSA for children and adolescents with a negative RADT. However, a throat culture is not considered necessary for adults with a negative RADT, because of the low likelihood that it will change management.9
The IDSA does not recommend routine follow-up posttreatment throat culture or RADT.9
False-positive tests for streptococcal infection can occur when the patient is colonized with GABHS but is not the cause of the acute disease.
False-negative tests for streptococcal infection can occur from poor sampling technique.
A positive mono spot (likelihood ratio in the first week of illness: 5.7) and/or greater than 40% atypical lymphocytes on the peripheral smear (likelihood ratio: 39) indicate mononucleosis.11
Viral cultures obtained from vesicles can be obtained in Coxsackievirus and herpes infections, but the diagnosis is usually based on clinical suspicion and findings.
Ultrasonography can assist in the diagnosis and localization of peritonsillar abscess, and computed tomography scan should be obtained if further extension into the deeper neck is suspected.12
Infectious mononucleosis—Nausea, anorexia without vomiting, uvular edema, generalized symmetric lymphadenopathy, and lethargy particularly in teenagers and young adults, is more suggestive of acute mononucleosis (Epstein-Barr virus [EBV]) although the pharyngeal examination has a similar appearance to GABHS (see Figure 37-4). Hepatosplenomegaly is indicative of EBV in this group.
Herpangina/Coxsackievirus infection—Oropharyngeal vesicles and ulcers indicate herpangina, which is caused by Coxsackievirus A16 in most cases (Figure 37-9).
Oral Candida—Whitish plaques of the oropharyngeal mucosa indicate oral Candida/thrush, which is mainly found in infants but can be found in adults with immunosuppression (see Chapter 142, Candidiasis).
Sexually transmitted infections—Primary human immunodeficiency virus, gonococcal, and syphilitic pharyngitis can all present with the symptom of sore throat. Although uncommon, these diagnoses should be considered in high-risk populations.
Primary herpes gingivostomatitis causes oral ulcers and pain in the mouth. The wide distribution of ulcers with the first case of herpes simplex virus (HSV)-1 distinguishes this infection from other types of pharyngitis (see Chapter 135, Herpes Simplex).
Cytomegalovirus (CMV)—Primary CMV infection in the immunocompetent host is usually asymptomatic. In the immunocompromised host, CMV may present with a mononucleosis-like syndrome clinically indistinguishable from EBV infection.
Deep neck infections—Asymmetry of the neck, neck masses, and any displacement of the peripharyngeal wall should raise suspicion. Associated shortness of breath may be a warning sign of impending airway obstruction. Other complications include aspiration, thrombosis, mediastinitis, and septic shock.
Epiglottitis—Rapid-onset fever, malaise, sore throat, and drooling in the absence of coughing characterize acute epiglottitis, especially when presenting in children. Progression of the disease can lead to life-threatening airway obstruction. Fortunately, this is a rare condition because of the preventive effect of the Haemophilus influenzae type b (HIB) vaccine.
Supraglottitis—Similar symptoms to epiglottitis, although seen in adults. Sore throat and painful swallowing are the most common presenting symptoms, seen in more than 90% of cases. Muffled voice and drooling, dyspnea, stridor, and cough are reported in less than 50% of cases. No definite organism is identified in most cases. Unlike epiglottitis in children, HIB is responsible for less than 20% of adult cases but still accounts for the majority of positive cultures. Mortality rates have been reported up to 20%. Currently more common than epiglottitis, because of HIB vaccine.
Diphtheria—A rare condition in the United States today, as most patients have been immunized. However, it needs to be considered, especially in unvaccinated and immigrant populations. Pharyngeal diphtheria presents with sore throat, low-grade fever, and malaise. The pharynx is erythematous with a grayish pseudomembrane that cannot be scraped off. Complications include myocarditis resulting in acute and severe congestive heart failure (CHF), endocarditis, and neuropathies.
Other bacterial causes—Non–group A Streptococcus, Fusobacterium necrophorum, Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Arcanobacterium haemolyticum have all been isolated as bacterial causes of pharyngitis; not as clinically significant, but all generally respond to treatments prescribed for strep pharyngitis.
Herpangina in a child caused by Coxsackievirus A16. (Reproduced with permission from Emily Scott, MD.)
Hydration with plenty of liquids (children and adults).
Salt-water gargles (children and adults).
Lozenges for comfort (adults only).
Age-appropriate dosing of acetaminophen (e.g., 1 g every 6 hours for adults) and ibuprofen may be used for symptomatic relief of fever and pain. Doses can be alternated as needed.
Antibiotic use—Use a clinical prediction rule (given above [see "Clinical Features"]) and/or RADT or culture for determining need to treat for GABHS9–11: SORⒶ Antibiotics for GABHS shorten symptom duration by about 1 day and prevent suppurative (otitis media, sinusitis, and peritonsillar abscess) and nonsuppurative (rheumatic fever) complications. Conversely, antibiotics have a 20% rate of adverse effects compared with 5% for placebo.11
Low probability (patients with predominantly viral symptoms, adults scoring 0 points on the modified Center score, negative RADT in an adult, negative throat culture): Treat symptomatically without antibiotics.
Intermediate probability (test and treatment based on result of RADT or culture): Patients with 1 to 3 points (probability of GABHS is approximately 18%) should undergo a rapid antigen test and be treated with antibiotics if positive.11
High probability (patients with 4 to 5 points on the modified Center score, all those with positive RADT or culture) should be considered for antibiotic treatment.
For suspected or proven GABHS, penicillin V 500 mg orally 2 times daily for 10 days continues to be the treatment of choice for adolescents and adults.9 Oral cephalexin (20 mg/kg/dose twice daily [max = 500 mg/dose]), cefadroxil (30 mg/kg once daily [max = 1 g]), clindamycin (7 mg/kg/dose 3 times daily [max = 300 mg/dose]), azithromycin (12 mg/kg once daily [max = 500 mg/dose]), OR clarithromycin (7.5 mg/kg/dose twice daily [max = 250 mg/dose]) can be used in penicillin-allergic patients. Penicillin G 1.2 million U IM single dose may be used for adults (<27 kg: 600,000 U) if unable to tolerate oral medication. For children: Pen VK 250 mg twice or 3 times daily OR amoxicillin 50 mg/kg once daily for 10 days. In some cases amoxicillin 25 mg/kg per day in divided doses every 12 hours is preferred because of palatability.
Needle aspiration or incision and drainage AND combination Penicillin G (600 mg IV every 6 hours for 24 to 48 hours) with metronidazole (15 mg/kg IV more than 1 hour followed by 7.5 mg/kg IV more than 1 hour every 6 to 8 hours) is recommended for peritonsillar abscess, based primarily on case series.13
Steroids (e.g., dexamethasone single 10-mg injection) can be used in severe tonsillitis in patients without immunocompromise. SORⒸ Authors of a Cochrane review of eight trials of pharyngitis found a reduction of 6 hours to onset of pain relief with corticosteroids and mean time to complete resolution of pain by 14 hours.14 Number needed to treat was <4 to prevent one person continuing to experience pain at 24 hours. The IDSA does not recommend use of corticosteroids as adjunctive treatment.9 There are insufficient data to determine efficacy of steroids for patients with mononucleosis.15
In extreme cases of pharyngitis, 1 teaspoon of viscous lidocaine 2% in a half glass of water gargled 20 to 30 minutes before meals helps the odynophagia. This is typically only recommended in rare cases because of risk of aspiration, potential toxicity of lidocaine, and the risk for oral mucosal burns—consider hospitalization if symptoms are this severe.
If signs of airway impairment are present, the patient should be immediately transported to an emergency department. Intubation can be extremely difficult and risky.
Refer patients with peritonsillar abscess to ear, nose, and throat (ENT). Incision and drainage is the treatment of choice in addition to using systemic antibiotics.
Consider ENT referral for tonsillectomy in proven recurrent GABHS cases, or under certain other conditions (e.g., antibiotic allergies/intolerances) with recurrence.16
Sore throat, regardless of the cause, is typically self-limiting. Typical symptoms last 3 to 4 days.
Longer-term complications are rare, but antibiotic treatment to prevent these sequelae remains justification for treatment. Antibiotics shorten the duration of illness by approximately 1 day and can reduce the risk of rheumatic fever by approximately two-thirds in communities where this complication is common.11 However, GI symptoms such as mild diarrhea are common side effects of antibiotic therapy.
Follow up if clinically deteriorating, especially if swallowing or breathing becomes more difficult or severe headache develops.
The treatment for most cases of non-GABHS pharyngitis is education. Explain to patients the difference between a viral and a bacterial infection to help them understand why antibiotics were prescribed or not prescribed. Antibiotic treatment for a patient with an obvious viral infection is inappropriate, despite patient requests. Studies demonstrate that spending time with the patient to explain the disease process is associated with greater patient satisfaction than prescribing an antibiotic.17,18
Rest, liquids, and analgesics should be encouraged.
Patients receiving antibiotics should be reminded to complete the entire course, even if symptoms improve. Common antibiotic side effects, such as rash, nausea, and diarrhea, should be reviewed.
Patients with mononucleosis and splenomegaly should be warned to avoid contact sports because of the risk of splenic rupture.
et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clin Infect Dis.
et al. Deep neck infection: a present-day complication. A retrospective review of 83 cases (1998–2001). Eur Arch Otorhinolaryngol.
MH. Diagnosis of streptococcal pharyngitis. Am Fam Physician.
M. Rapid antigen detection test for group A streptococcus in children with pharyngitis. Cochrane Database Syst Rev. 2016;(7):CD010502.
et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clin Infect Dis.
A, High Value Care Task Force of the American College of Physicians and for the Centers for Disease Control and Prevention. Appropriate antibiotic use for acute respiratory tract infection in adults: advice for high-value care from the American College of Physicians and the Centers for Disease Control and Prevention. Ann Intern Med.
MH. Sore throat. In: Sloane
et al, eds. Essentials of Family Medicine. Baltimore, MD: Lippincott Williams & Wilkins; 2012:207–216.
et al. Emergency imaging assessment of deep neck space infections. Semin Ultrasound CT MR.
JA. An evidence-based review of peritonsillar abscess. Clin Otolaryngol.
et al. Corticosteroids as standalone or add-on treatment for sore throat. Cochrane Database Syst Rev. 2012;(10):CD008268.
et al. Steroids for symptom control in infectious mononucleosis. Cochrane Database Syst Rev. 2015;(11):CD004402.
et al. Clinical practice guideline: tonsillectomy in children. Otolaryngol Head Neck Surg.
DA. Antibiotics and respiratory infections: are patients more satisfied when expectations are met? J Fam Pract.
et al. Antibiotic use for emergency department patients with upper respiratory infections: prescribing practices, patient expectations, and patient satisfaction. Ann Emerg Med.