What to do for a 12-month-old with persistent hyperthermia (fever) despite being on antibiotics for streptococcal pharyngitis (strep throat)?

Persistent Fever in 12-Month-Old on Antibiotics for Strep Throat

Immediate Assessment and Action

Reassess the diagnosis and consider treatment failure, as fever should improve within 48-72 hours of appropriate antibiotic therapy for streptococcal pharyngitis. 1, 2

Key Clinical Decision Points

First, verify the original diagnosis was correct:

• Children under 3 years should generally NOT be tested or treated for strep throat due to extremely low incidence of Group A Streptococcus (GAS) pharyngitis and near-zero risk of acute rheumatic fever in this age group 1, 3
• At 12 months, GAS infection typically presents with fever, mucopurulent rhinitis, excoriated nares, and diffuse adenopathy—NOT the classic exudative pharyngitis seen in older children 3
• If the child has cough, rhinorrhea, hoarseness, or oral ulcers, this strongly suggests viral pharyngitis, not strep 1, 3

If strep was confirmed by rapid test or culture, evaluate for treatment failure:

• Fever persisting beyond 48-72 hours indicates either inadequate antibiotic coverage, resistant bacteria, suppurative complications, or concurrent viral infection 1, 2
• Examine for suppurative complications: peritonsillar abscess, cervical lymphadenitis, or mastoiditis 1

Management Algorithm

If Original Diagnosis Was Strep (Confirmed by Testing)

Step 1: Verify antibiotic choice and adherence

• First-line treatment should be amoxicillin 50 mg/kg once daily (max 1000 mg) or 25 mg/kg twice daily (max 500 mg per dose) for 10 days 1, 2, 4
• Penicillin V 250 mg 2-3 times daily for 10 days is alternative 1, 2
• Confirm parents are actually giving the medication as prescribed 5

Step 2: If on appropriate antibiotic with good adherence, switch therapy

• If initially on amoxicillin: Switch to amoxicillin-clavulanate 40 mg/kg/day (amoxicillin component) divided in 3 doses for 10 days 1
• If already on amoxicillin-clavulanate or oral cephalosporin: Give intramuscular ceftriaxone 50 mg/kg as single dose (can repeat for 3-day course) 1
• Consider clindamycin 20-30 mg/kg/day in 3 doses (max 300 mg/dose) for 10 days if penicillin resistance suspected 1

Step 3: Symptomatic management

• Acetaminophen or ibuprofen for fever control and comfort 1, 2, 6
• Never use aspirin in children due to Reye syndrome risk 1, 2, 3
• Ensure adequate hydration 2

If Original Diagnosis Was Likely Wrong

Most probable scenario: This is viral pharyngitis, not strep

• Stop antibiotics if diagnosis was not confirmed by testing 1, 3
• Provide symptomatic treatment only: acetaminophen or ibuprofen for fever and pain 3, 6
• Viral pharyngitis can cause fever for 3-5 days or longer 6
• Reassure parents that fever itself is not harmful and focus on overall comfort rather than temperature normalization 6

Red Flags Requiring Urgent Evaluation

Seek immediate evaluation if any of the following develop:

• Difficulty breathing, drooling, or inability to swallow (suggests peritonsillar abscess or epiglottitis) 1
• Severe neck swelling or tender neck mass (cervical lymphadenitis) 1
• Toxic appearance, lethargy, or decreased responsiveness 6
• Persistent high fever beyond 5 days despite appropriate antibiotics 1

Common Pitfalls to Avoid

• Testing children under 3 years for strep without specific risk factors (such as older sibling with confirmed GAS) is inappropriate and leads to overtreatment 1, 3
• Assuming all pharyngitis with fever is bacterial—most cases in this age group are viral 1, 3
• Focusing on fever normalization rather than overall clinical improvement—fever is a physiologic response, not the disease itself 6
• Not considering concurrent viral infection—42-49% of children with persistent symptoms on antibiotics have sterile middle ear fluid, suggesting viral co-infection 1
• Inadequate antibiotic dosing—ensure weight-based dosing is correct, as underdosing leads to treatment failure 1, 4

Bottom Line

For a 12-month-old with persistent fever on antibiotics for "strep," the most likely scenario is that this was never strep throat to begin with, but rather viral pharyngitis that was inappropriately treated. 1, 3 Stop antibiotics, provide symptomatic care, and monitor for red flags. If strep was definitively confirmed by testing and appropriate antibiotics were given with good adherence, switch to amoxicillin-clavulanate or consider intramuscular ceftriaxone while evaluating for suppurative complications. 1