Signs of Strep Throat in Adults
Adults with strep throat typically present with sudden-onset severe sore throat, fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and notably absent cough. 1, 2
Core Clinical Features Suggesting Bacterial (Strep) Infection
The modified Centor criteria help identify adults who warrant testing for Group A Streptococcus: 1
- Fever (by history or measured) 1, 2
- Tonsillar exudates (white or yellow patches on tonsils) 1, 2
- Tender anterior cervical lymphadenopathy (swollen, painful lymph nodes in front of neck) 1, 2
- Absence of cough (cough strongly suggests viral etiology instead) 1, 3
Additional Signs Supporting Strep Diagnosis
- Sudden onset of throat pain (rather than gradual progression) 1, 4
- Headache 1, 2
- Nausea, vomiting, and abdominal pain 1, 2
- Swollen tonsils with inflammation of pharynx 1
- Palatal petechiae (small red spots on soft palate) 1, 2
- Scarlatiniform rash (sandpaper-like rash) 1
- Beefy red swollen uvula 2
Clinical Decision-Making Algorithm
If the patient has 3 or more Centor criteria, proceed with rapid antigen detection test (RADT) or throat culture. 1 The risk of Group A strep infection correlates with the number of criteria present: 1
- 4 criteria present: 51-56% probability of strep 1
- 3 criteria present: 28-35% probability 1
- 2 criteria present: 11-17% probability 1
- Fewer than 3 criteria: Testing generally not needed 1
Signs That Suggest Viral (NOT Strep) Infection
Do NOT test or treat for strep if the patient has: 1
- Cough 1, 2
- Nasal congestion or rhinorrhea 1, 2, 4
- Conjunctivitis 1
- Hoarseness 1, 2
- Diarrhea 1, 2
- Oropharyngeal ulcers or vesicles 1, 2
Red Flag Signs Requiring Urgent Evaluation
These symptoms suggest serious complications like peritonsillar abscess, parapharyngeal abscess, epiglottitis, or Lemierre syndrome: 1, 5
- Difficulty swallowing with drooling 1, 5
- Neck tenderness or swelling 1, 5
- Muffled voice 5
- Trismus (inability to open mouth) 5
- Tonsillar asymmetry (one tonsil pushed medially) 5
- Severe pharyngitis in adolescents/young adults (consider Fusobacterium necrophorum and Lemierre syndrome) 1, 5
Critical Clinical Pitfalls
- Only 5-10% of adults with sore throat actually have Group A strep pharyngitis, yet over 60% receive antibiotics—massive overtreatment. 1, 3
- Clinical diagnosis alone is insufficient—even experienced physicians cannot reliably distinguish strep from viral pharyngitis without testing. 1, 2, 6
- Negative rapid antigen test in adults does NOT require confirmatory throat culture (unlike in children), given the low prevalence of strep and very low risk of rheumatic fever in adults. 1
- Group C and G streptococci can cause severe pharyngitis but are not routinely tested for, and their clinical significance remains unclear. 1, 7
Testing Recommendations
- Test adults with ≥3 Centor criteria using rapid antigen detection test and/or throat culture before prescribing antibiotics. 1
- Do NOT test patients with clear viral symptoms (cough, rhinorrhea, conjunctivitis) as this identifies carriers rather than true infections. 1, 4
- Do NOT test asymptomatic household contacts. 4