Can teething cause fever in infants and toddlers?

Can Teething Cause Fever?

Teething can cause a mild temperature elevation (up to approximately 38.0°C/100.4°F), but it does not cause clinically significant fever (≥38.2°C/100.8°F or higher), and attributing fever to teething risks missing serious bacterial infections in infants.

Evidence on Temperature Elevation During Teething

The largest prospective study of 125 healthy infants tracking 475 tooth eruptions found that mild temperature elevation was statistically associated with teething, but this elevation was minimal 1. Critically, no teething child in this study had a fever of 104°F (40°C), and none had a life-threatening illness 1. The study defined the "teething period" as 4 days before tooth emergence through 3 days after (an 8-day window), and even during this period, temperature elevation occurred in fewer than 35% of teething infants 1.

A second prospective cohort study of 21 children (tracking 90 teeth over 236 "toothdays") found that child temperatures were essentially identical on tooth eruption days versus non-tooth days (36.21°C vs 36.18°C), with no statistical association between tooth eruption and fever 2. When fever was defined as temperature >37.5°C, logistic regression showed no significant relationship (OR = 1.35,95% CI = 0.80-2.27 for high fever; OR = 1.34,95% CI = 0.48-3.77 for low fever) 2.

A third study examining the 20 days before first tooth eruption in 46 infants found that 20 infants had temperatures >37.5°C on the day of eruption (day 0), compared with 7 or fewer infants on days 4-19 before eruption 3. However, the authors emphasized the danger of attributing fever to teething rather than endorsing teething as a cause 3.

Clinical Implications and Serious Infection Risk

The American Academy of Pediatrics guidelines for febrile infants establish that fever is defined as rectal temperature ≥38.0°C (100.4°F) 4. In the post-pneumococcal vaccine era, serious bacterial infections (SBI) still occur in 7-9% of febrile infants under 3 months, with urinary tract infections accounting for over 90% of these cases 5. Even well-appearing infants can harbor serious infections—only 58% of infants with bacteremia or bacterial meningitis appear clinically ill 6, 5.

For infants with temperatures <38.2°C, one large study found that 7.5% still had serious infections, including urinary tract infections (5.8%), bacteremia (0.8%), and bacterial meningitis (0.4%) 7. This demonstrates that using teething as an explanation for even mild temperature elevation would miss a clinically important number of serious infections 7.

Algorithmic Approach to Fever in Teething-Age Infants

When Temperature is <38.0°C (100.4°F):

• This may represent the mild temperature elevation associated with teething 1
• Monitor closely and reassess if temperature rises or infant develops concerning symptoms 1
• Do not perform invasive testing solely for this temperature 4

When Temperature is ≥38.0°C (100.4°F):

• Never attribute this to teething alone 1, 3
• Perform age-appropriate evaluation for serious bacterial infection 4:
  • Infants 0-28 days: Comprehensive evaluation including blood culture, urine culture (catheterized specimen), and lumbar puncture 6, 5
  • Infants 29-90 days: Blood culture, catheterized urine culture, and strongly consider lumbar puncture 4, 5
  • Infants >90 days to 2 years: Risk-stratify based on clinical appearance, duration of fever, and presence of localizing signs; obtain urinalysis and urine culture especially in high-risk groups (uncircumcised males, females, temperature ≥39°C, fever ≥2 days) 4

When Fever Persists ≥5 Days:

• Immediately evaluate for Kawasaki disease, which requires fever ≥5 days plus ≥4 of 5 principal features (conjunctival injection, oral changes, rash, extremity changes, cervical lymphadenopathy ≥1.5 cm) 8
• Obtain inflammatory markers (ESR, CRP) and urgent echocardiography if Kawasaki disease is suspected 8
• Incomplete Kawasaki disease is especially common in infants <1 year and carries higher risk of coronary complications 8

Critical Pitfalls to Avoid

• Do not assume teething explains any fever ≥38.0°C (100.4°F) 1, 3
• Do not rely on clinical appearance alone—well-appearing infants can have serious bacterial infections 6, 5
• Do not use bag-collected urine specimens for diagnosis; only catheterized or suprapubic specimens are acceptable 4
• Do not dismiss persistent fever (≥5 days) without evaluating for Kawasaki disease, as delayed treatment beyond 10 days significantly increases coronary artery aneurysm risk 8
• Remember that viral and bacterial infections can coexist—a positive viral test does not exclude bacterial infection 8, 5

Other Teething-Associated Symptoms

Beyond temperature, the prospective study found that increased biting, drooling, gum-rubbing, irritability, and decreased appetite for solids were statistically associated with teething, but no symptom occurred in >35% of teething infants 1. Importantly, congestion, vomiting, diarrhea, and rashes other than facial rashes were not significantly associated with tooth emergence 1. A second study found only parent-reported (but not staff-reported) loose stools weakly associated with eruption, and this association disappeared when the time window was adjusted 2.