What is the diagnosis and treatment for a patient, possibly with a compromised immune system, presenting with petechiae on the palate and a sore throat?

Diagnosis and Management of Petechiae on Palate with Sore Throat

The most likely diagnosis is Group A Streptococcal (GAS) pharyngitis, and you should immediately perform a rapid antigen detection test (RADT) followed by throat culture if negative, then treat with penicillin or amoxicillin for 10 days if confirmed positive. 1, 2

Key Diagnostic Features

Palatal petechiae are highly suggestive of streptococcal pharyngitis when present alongside other classic findings. 1 The American Academy of Family Physicians identifies palatal petechiae (described as "doughnut lesions") as a characteristic physical examination finding that strongly points toward GAS infection. 1

Classic Strep Throat Presentation Includes:

• Tonsillopharyngeal erythema with or without exudates 1
• Tender, enlarged anterior cervical lymph nodes 1
• Palatal petechiae (the finding in your patient) 1
• Beefy red, swollen uvula 1
• Fever (typically high-grade) 1
• Absence of viral features (no cough, rhinorrhea, conjunctivitis, or hoarseness) 3, 4

Critical Diagnostic Algorithm

Step 1: Rule Out Viral Etiology

If the patient has cough, rhinorrhea, conjunctivitis, or hoarseness, this strongly suggests viral pharyngitis and testing for GAS is NOT indicated. 3, 4 The presence of these viral features makes bacterial infection unlikely. 4

Step 2: Confirm GAS Diagnosis

You must obtain microbiological confirmation—clinical findings alone, even palatal petechiae, cannot definitively diagnose GAS without laboratory testing. 1, 2

• Perform RADT immediately at the point of care 2
• If RADT is positive, this is diagnostic and you can start treatment immediately 2
• If RADT is negative, obtain a backup throat culture (gold standard, results in 18-24 hours) 2

Step 3: Consider Alternative Diagnoses

While GAS is most likely, other conditions can present with palatal petechiae:

Infectious Mononucleosis (EBV): Suspect in patients aged 10-30 years with sore throat, significant fatigue, palatal petechiae, posterior cervical or auricular adenopathy, and marked lymphadenopathy. 5 Look for atypical lymphocytosis ≥20% on CBC and positive heterophile antibody test. 5

In immunocompromised patients specifically: Consider broader infectious causes, though the evidence does not suggest a different initial approach to palatal petechiae. 3

Treatment Protocol

For Confirmed GAS Pharyngitis:

First-line therapy is oral penicillin V or amoxicillin for 10 days. 2

Specific dosing:

• Penicillin V: 250 mg PO two to three times daily for 10 days (children) 2
• Amoxicillin: 50 mg/kg once daily (maximum 1,000 mg) for 10 days 2
• Penicillin G benzathine IM: Single dose of 600,000 units if <27 kg or 1,200,000 units if ≥27 kg (use if compliance concerns) 2

For penicillin allergy:

• First-generation cephalosporins (cephalexin or cefadroxil) 2
• Non-beta-lactam alternatives: clindamycin, clarithromycin, or azithromycin (use macrolides cautiously due to increasing resistance) 2

Symptomatic Management:

• Acetaminophen or NSAIDs for fever and throat pain 2
• Avoid aspirin in children (Reye's syndrome risk) 2
• Do not use corticosteroids routinely (minimal benefit) 2

Treatment Goals

Antibiotic therapy achieves: 2

• Prevention of acute rheumatic fever
• Reduction in symptom duration (1-2 days shorter) 3
• Prevention of suppurative complications
• Reduced transmission to contacts

Critical Pitfalls to Avoid

Do not treat based on clinical findings alone without laboratory confirmation. Even experienced clinicians cannot reliably distinguish streptococcal from viral pharyngitis on physical examination alone. 1 The modified Centor score of 4 (fever, exudates, adenopathy, no cough) only corresponds to a 51-56% probability of GAS infection. 2

Do not test or treat if viral features are present. More than 60% of adults with sore throat receive unnecessary antibiotics. 3 Testing should not be performed when cough, rhinorrhea, or other viral symptoms are present. 4

In the immunocompromised patient context mentioned: While the guideline scope excludes immunosuppression, 3 the initial diagnostic approach remains the same—confirm GAS with testing before treating, but maintain higher vigilance for complications and consider broader infectious workup if initial testing is negative.