Acute pharyngitis is one of the most common illnesses seen in the primary care setting accounting for up to 1.2 % of all emergency department visits and up to 6 % of office visits for children and adolescents [4, 5]. Most cases in children are observed during winter and early spring when respiratory viruses are more common. During the summer months enteroviruses are responsible for the majority of cases [6]. Tonsillitis caused by Group A β-hemolytic streptococcus (GABHS) most commonly occurs in children 5–15 years old, affecting less than 15 % of children younger than 3 years old, 24 % of children less than 5 years old, and 37 % of school-aged children [7]. The financial burden of GABHS tonsillitis is estimated to be between $224 and $539 million per year with more than half being associated to non-medical costs [8]. Neisseria gonorrhoeae is an important pathogen in sexually active individuals or in victims of sexual abuse [6]. Repeated episodes of all-cause tonsillitis is reported in 0.9 % of children less than 1 year old and 5.3 % of children between the ages of 1 and 4 years old [9].

Tonsillitis may be caused by a viral or bacterial infection of the tonsils, most commonly the palatine tonsils. Viral etiologies are the most common cause of tonsillitis in the pediatric population. Common viral pathogens include enteroviruses, particularly coxsackie virus, respiratory viruses (e.g. adenovirus, rhinovirus, influenza virus, coronavirus, parainfluenza virus and respiratory syncytial virus), and viruses of the herpesviridae family like Epstein-Barr Virus (EBV), cytomegalovirus (CMV) and herpes simplex virus (HSV) [7]. The most common bacterial pathogen implicated in acute tonsillitis is GABHS, accounting for up to 30 % of all episodes of acute pharyngotonsillitis in children. Less frequent bacterial causes include Staphylococcus aureus, Streptococcus pneumoniae, Group C streptococcus, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Corynebacterium diphtheriae, Arcanobacterium haemolyticum, Neisseria gonorrhea, Francisella tularensis, Yersinia enterocolitica, and mixed anaerobic flora from the oral cavity [7]. Fusobacterium necrophorum, a gram-negative aerobic bacilli, and the most common cause of Lemierre’s syndrome, has been cultured from adolescents and young adults with uncomplicated tonsillitis [10].

Patients with tonsillitis present with a variety of symptoms that include sore throat, fever, chills, odynophagia, cervical adenopathy, trismus, halitosis, erythematous and exudative tonsils and tonsillar pillars (Fig. 10.2). The presence of conjunctivitis, coryza, cough, stomatitis, diarrhea and hoarseness strongly suggest a viral etiology. Children younger than 3 years of age may have an atypical presentation of GABHS infection called streptococcosis, which is characterized by fever, mucopurulent or serous rhinitis, and adenopathy, followed by irritability, loss of appetite and lethargy. Exudative tonsillitis is rare in this age group. On physical exam, it is often difficult to distinguish between viral and bacterial tonsillitis, but some clinical findings may provide important clues of the etiologic agent. For example, HSV typically presents with stomatitis, EBV may include lymphadenitis and coxsackie virus infections may present with throat ulcers (herpangina) or as part of hand-foot-mouth disease.

Complications of tonsillitis can be suppurative or non-suppurative in nature. Suppurative complications include peritonsillar abscess, parapharyngeal or retropharyngeal space abscess, and suppurative cervical lymphadenitis. Acute airway compromise, rheumatic fever, glomerulonephritis, and scarlet fever are non-suppurative complications of tonsillitis caused by GABHS. Streptococcal toxic shock syndrome, an uncommon but rapidly progressive disease, can complicate cases of pharyngitis caused by a toxic-producing strain of GABHS [11].

Tonsillitis is primarily a clinical diagnosis. Supportive tests include throat cultures, GABHS rapid antigen test, and anti-streptolysin-O (ASO), anti-deoxyribonuclease B (anti-Dnase B), anti-hyaluronidase and anti-streptokinase antibody titers [12]. Other tests may be helpful based on clinical suspicion, for example, EBV specific serology or Monospot (heterophile antibody) test, EBV polymerase chain reaction (PCR) or HSV PCR as needed. The monospot test is particularly insensitive in young children, with only 25–50 % of children under the age of 12 years infected with EBV having a positive Monospot test [13]. Specific EBV serology to detect antibodies against viral capsid antigens (VCA) that includes VCA-IgG and VCA-IgM in conjunction with antibodies against Epstein-Barr nuclear antigen or EBNA are the preferred diagnostic method in this age group. A real-time EBV PCR assay is helpful in patients with immunocompromising conditions and to confirm the diagnosis in patients with negative serology but strong clinical suspicion of infection [14].

The most important step in diagnosis is distinguishing between viral and GABHS tonsillitis as anti-bacterial agents are not effective in the treatment viral tonsillitis. Furthermore, with a few rare exceptions (e.g. Arcanobacterium haemolyticum, Neisseria gonorrhoeae and Fusobacterium spp.) anti-microbial treatment is not beneficial for bacterial causes of tonsillitis except GABHS given that there is not a significant reduction in the rate of complications or in duration of clinical symptoms [7]. Seventy percent of patients presenting with sore throat are treated with antibiotics while only 20–30 % have documented GABHS tonsillitis. Antibiotic treatment may be associated with adverse drug events that range from mild diarrhea to severe allergic reactions. Thus, the utility of these drugs must be determined in order to avoid potential selection of resistant organisms, exposure to adverse events associated with anti-microbial use, and extra cost. Treatment of GABHS is instrumental in preventing the potentially long-term and life-threatening complications associated with this pathogen, specifically and most importantly, ARF. Treatment also aids in the control of acute signs and symptoms, prevention of suppurative complications, and decreased transmission of GABHS to close contacts [7]. Throat pain and fever self-resolve by 1 week and 3–5 days, respectively, after onset if left untreated; if treated, both symptoms resolve within 3 days [15]. The organisms are eradicated from the pharynx after 10 days of treatment. ARF can be prevented even if therapy is initiated after 9 days of onset [11]. Of note, treatment does not prevent the development of PSGN [7].

The Infectious Disease Society of America (IDSA) recommends testing for GABHS unless a patient presents with symptoms strongly suggestive of a viral etiology; examples of such symptoms include cough, coryza, rhinorrhea, stomatitis or hoarseness. Testing for GABHS is also not indicated in children less than 3 years old. Children in this age group do not present with classic symptoms of GABHS tonsillitis and the incidence of ARF is rare, affecting approximately 0.2 % of children [7, 9]. Testing for GABHS in these children should only be pursued in the presence of other risk factors such as school-aged sibling with documented infection by GABHS, close household contact with diagnosis of symptomatic disease, or with personal or family history of a GABHS complication (ARF) [7].

One of the most commonly used in-office diagnostic tests for GABHS is the Rapid Antigen Detection Test (RADT). This test is done via throat swab of the surface of either tonsil or tonsillar fossa and posterior pharyngeal wall. Swabs of other areas of the oropharynx or oral cavity may lead to false negatives. An enzyme immunoassay test with turn-around times as little as 5 min is then done. It is 95 % specific and 70–90 % sensitive based on the type or manufacturer of RADT used. In the case of a positive RADT, children should be treated with antibiotics. In the case of a negative RADT, the IDSA recommends a throat culture be done during the same office visit. Due to the variability in sensitivity of RDTA based on manufacturer, the high rate of GABHS in children and implications of complications, a throat culture is recommended in order to capture any false negatives. The rapid turnaround time for RADT makes it useful for rapid identification and treatment of GABHS. Rapid treatment decreases the risk of spread of GABHS among close contacts, the amount of time missed from school or work for caregivers, and the duration and severity of acute signs and symptoms of GABHS tonsillitis [7].

Throat cultures are recommended in children in the case of negative RADT prior to the administration of antibiotics in order to avoid false negative results. A single throat swab has a 90–95 % sensitivity rate when done correctly. A throat swab similar to the RADT test is done and is then either processed in an in-office laboratory or sent to a microbiology laboratory. If the cultures are grown in-office, specific instructions must be followed. The swab is processed on a sheep’s blood agar plate and incubated at 35–37 °C for 18–24 h. While treatment decisions can be made based on growth patterns at 24 h, a plate with no growth should be re-examined at 48 h to ensure a correct diagnosis. Two major disadvantages of using throat cultures for diagnostic purposes are the training and cost associated with accurate testing as well as delayed diagnosis due to processing time. However, even a delayed diagnosis can be beneficial. Studies show that treatment of GABHS tonsillitis can be delayed up to 9 days from the onset of symptoms and still effectively prevent complications such as ARF [7, 16, 17]. Therefore, regardless of the delay in treatment, throat cultures should be done in children with negative RADT [7].

Other testing options include anti-streptococcal antibody titers; however, these titers are not helpful in the diagnosis of acute GABHS tonsillitis. Rather, they are indicative of previous infection. Antibody titers become positive 3–8 weeks after an acute infection and may persist for up to a year after the resolution of the infection. Thus, they may be useful in determining the etiology of complications [7, 17, 18].

Children with recurrent tonsillitis are sometimes chronic carriers of GABHS with superimposed viral infections. Up to 20 % of asymptomatic school aged children can be carriers of GABHS in the winter and spring months [7, 19]. The IDSA does not recommend identification or treatment of these chronic carriers for several reasons. Distinguishing chronic carriers from recurrent acutely infected children is not possible with the current diagnostic modalities, chronic carriers of GABHS are unlikely to spread bacteria to close contacts and they are at minimal to no risk of developing complications of GABHS [7]. Moreover, eradication of GABHS from colonized tonsils and adenoids is much more difficult than treatment of acute GABHS tonsillitis. However, certain specific circumstances do call for treatment of chronic carriers of GABHS [7]. These indications, along with treatment options, are discussed below in the section entitled “Treatment of Tonsillitis.”

Routine post-treatment RADT or throat cultures to confirm eradication of GABHS are not recommended. Post-treatment testing can be pursued in the case of a patient at high risk for developing ARF (personal or family history of ARF) or recurrent classic symptoms of GABHS tonsillitis shortly after the completion of treatment. Testing or treatment of asymptomatic household contacts is not recommended as it has not been shown to decrease the incidence of subsequent GABHS tonsillitis [7].

Treatment of viral tonsillitis primarily consists of supportive measures including bed rest, hydration, analgesics, and oral hygiene. Most cases of viral tonsillitis self-resolve in 3–4 days. Recommended analgesics include acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs). Aspirin should be avoided due to the risk of Reye’s syndrome, a rare severe illness characterized by rapidly progressive encephalopathy with liver dysfunction and a mortality rate of up to 40 % in children and adolescents suffering from a viral infection, especially varicella-zoster or influenza, in association with the use of salicylates [20]. Other NSAIDs such as ibuprofen or diclofenac can be used. NSAIDs and acetaminophen not only provide pain control but also act to reduce fever. Corticosteroids have proven beneficial in the reduction of the duration and severity of other signs and symptoms, but they do not affect pain levels. Thus, they are not recommended for symptomatic control in acute tonsillitis [7, 21].

Acute bacterial tonsillitis is treated with anti-microbial therapy in addition to the supportive measures listed above. Penicillins target the most commonly implicated pathogen, GABHS. They are narrow spectrum drugs with the greatest safety profile and provide the highest efficacy at a lower cost than other alternatives. Furthermore, there have been no documented cases of penicillin resistant GABHS. A ten-day course of oral penicillin or amoxicillin or a one-time dose of intramuscular benzathine penicillin G is the treatment of choice. An amoxicillin suspension is preferred for younger children due to once a day dosing and better taste that facilitates improved compliance. While a clinical response should be achieved within 24–48 h of beginning antibiotic therapy, a 10 day course of antibiotics has been shown to achieve the maximum rates of pharyngeal eradication of bacteria [7].

Patients with previous non-anaphylactic allergic reactions to penicillin can be treated with first generation cephalosporins for 10 days. Narrow spectrum first generation cephalosporins such as cefadroxil and cephalexin are preferred over broad spectrum cephalosporins such as cefaclor, cefuroxime, cefixime, cefdinir, and cefpodoxime. Approximately 10 % of patients allergic to penicillins will also be allergic to cephalosporins. These patients can be treated with a 10 day course of clindamycin, clarithromycin or a 5 day course of azithromycin. Erythromycin should be reserved for treatment resistant infections due to its high rate of gastrointestinal side effects. Rate of GABHS antibiotic resistance in the United States are approximately 1 % to clindamycin and 5–8 % to macrolides [7, 22].

Ampicillin and oral penicillin-based antibiotics can cause a generalized papular rash in the setting of infectious mononucleosis. Thus, if infectious mononucleosis is suspected, treatment with antibiotics is not recommended.

The IDSA discourages the use of several antibiotics for the treatment of GABHS tonsillitis. Given the high prevalence of resistant strains of GABHS, tetracyclines are not recommended and trimethoprim-sulfamethoxazole does not effectively eradicate GABHS in acute tonsillitis. Newer fluoroquinolones such as levofloxacin and moxifloxacin have proven active against GABHS in vitro but no in vivo efficacy has been documented. Fluoroquinolones are also expensive, broad-spectrum antibiotics with emerging resistance to Streptococcus pneumoniae worldwide and are not recommended in children 18 years of age or younger due to their potential for joint and cartilage toxicity [7, 23, 24].