What are the typical signs and symptoms of group A streptococcal pharyngitis (strep throat)?

Typical Signs and Symptoms of Group A Streptococcal Pharyngitis

Group A streptococcal pharyngitis presents with sudden-onset severe sore throat, fever, painful swallowing, and tender anterior cervical lymph nodes, often with tonsillopharyngeal erythema and exudates—but clinical diagnosis alone is unreliable and laboratory confirmation with rapid antigen detection testing or throat culture is mandatory before treatment. 1

Classic Presenting Symptoms

The hallmark symptoms of strep throat include:

• Sudden onset of severe sore throat with pain on swallowing 1, 2
• Fever (typically >100.4°F or 38°C), often high-grade 1, 3, 4
• Headache commonly accompanies the throat symptoms 1, 5, 4
• Nausea, vomiting, and abdominal pain, particularly in children—this is an important pediatric presentation that can dominate the clinical picture 1, 5, 6

Key Physical Examination Findings

When examining a patient with suspected strep throat, look for:

• Tonsillopharyngeal erythema (redness of throat and tonsils) with or without exudates—this is the most consistent finding 1, 5, 6
• Tender, enlarged anterior cervical lymph nodes (bilateral cervical adenopathy) 5, 7, 3
• Tonsillar exudates (white or yellow patches on tonsils), though these may be absent 5, 3
• Palatal petechiae ("doughnut lesions")—highly suggestive when present 5
• Beefy red, swollen uvula 5, 6
• Scarlatiniform rash with sandpaper-like texture and "strawberry tongue" in cases of scarlet fever 6

Critical Features That Suggest VIRAL (Not Strep) Pharyngitis

Do not test or treat for strep throat when these viral features are present:

• Cough is the strongest predictor of viral etiology 1, 7, 3
• Rhinorrhea/coryza (runny nose) 1, 2
• Conjunctivitis (pink eye) 1, 5
• Hoarseness 1, 5
• Oral ulcers or vesicles 1, 5
• Diarrhea 1, 3

The presence of these features strongly suggests viral pharyngitis and testing for strep is not indicated 1.

Epidemiological Context That Increases Likelihood

Consider these factors when assessing probability:

• Age 5-15 years—strep throat is primarily a disease of this age group 1, 5, 7
• Winter and early spring in temperate climates 1, 5, 6
• Known exposure to documented strep throat case 5

In adults, strep pharyngitis accounts for only 5-15% of sore throats, compared to 15-30% in children 7, 4.

The Diagnostic Dilemma: Why Clinical Diagnosis Fails

Even the most experienced physicians cannot reliably distinguish strep from viral pharyngitis based on clinical findings alone. 1, 5 The IDSA guidelines emphasize that even when patients have all classic features, strep throat is confirmed only 35-50% of the time 1. This broad overlap between bacterial and viral presentations is why laboratory confirmation is mandatory 1.

Practical Clinical Algorithm Using Modified Centor Criteria

Use the modified Centor score to guide testing decisions 1, 7:

• Fever by history (1 point)
• Tonsillar exudates (1 point)
• Tender anterior cervical adenopathy (1 point)
• Absence of cough (1 point)

Management based on score:

• 0-1 points: No testing or antibiotics needed 1
• 2-3 points: Perform rapid antigen detection test (RADT) or throat culture 1, 7
• 4 points: Consider empiric treatment or testing 7

Testing Requirements

In children and adolescents: Negative RADT must be backed up with throat culture (the gold standard) because of the risk of rheumatic fever 1, 6. Positive RADTs do not need confirmation as they are highly specific 1.

In adults: Back-up throat cultures for negative RADTs are not routinely necessary given the low incidence of strep pharyngitis and exceptionally low risk of rheumatic fever in adults 1.

Common Pitfalls to Avoid

• Do not test asymptomatic household contacts of strep patients—this identifies carriers, not acute infections 4
• Do not test children under 3 years routinely, as acute rheumatic fever is extremely rare in this age group and they often present atypically 4
• Do not test patients with obvious viral features (cough, rhinorrhea, conjunctivitis)—this wastes resources and may lead to unnecessary antibiotic treatment of viral illness 1
• Remember that positive tests may represent asymptomatic carriers with concurrent viral pharyngitis, not true strep infection 6