What is the recommended prophylaxis for pediatric patients with a tick (Ixodes species) bite?

Prophylaxis for Pediatric Patients with Ixodes Tick Bites

For pediatric patients with Ixodes tick bites, prophylaxis with a single dose of doxycycline (4 mg/kg up to 200 mg) is recommended only when ALL of the following criteria are met: the tick is identified as an Ixodes species, was attached for ≥36 hours, prophylaxis can be started within 72 hours of tick removal, and the bite occurred in an area with ≥20% local rate of Borrelia burgdorferi infection in ticks. 1

Criteria for Prophylaxis

Prophylaxis should only be administered when ALL of the following conditions are met:

1. The tick is identified as an Ixodes species (deer tick)
2. The tick was attached for ≥36 hours
3. Prophylaxis can be started within 72 hours of tick removal
4. The bite occurred in a highly endemic area (≥20% tick infection rate)
5. The child is ≥8 years of age (for doxycycline use)

Recommended Prophylactic Regimen

• Children ≥8 years: Single dose of doxycycline 4 mg/kg (maximum 200 mg) 1, 2
• Children <8 years: Routine prophylaxis is not recommended; instead, use a "wait and watch" approach 1

Important Contraindications

• Children under 8 years of age (doxycycline contraindicated)
• Pregnant patients
• Patients with doxycycline allergy
• Tick attached <36 hours

• 72 hours since tick removal

• Low-endemic areas (<20% tick infection rates)
• Non-Ixodes species ticks

Rationale for Limited Prophylaxis

The Infectious Diseases Society of America (IDSA) recommends limited prophylaxis because:

• The risk of developing Lyme disease after a recognized tick bite in endemic areas is only 1-3.2% without prophylaxis 1
• Routine antimicrobial prophylaxis is not recommended due to potential adverse reactions and costs 3
• Most infected persons develop erythema migrans, which is diagnostic of early Lyme disease and can be treated effectively at that stage 3

Alternative Approach for Those Not Meeting Criteria

For patients who do not meet all criteria for prophylaxis, a "wait and watch" approach is recommended:

• Monitor for 30 days for symptoms of tick-borne illness 1
• Watch for development of erythema migrans (typically appears 7-14 days after tick detachment)
• Seek medical attention if symptoms develop

Common Pitfalls to Avoid

1. Inappropriate use of amoxicillin: Amoxicillin is not recommended as prophylaxis for those who cannot take doxycycline 1

2. Unnecessary serologic testing: Testing at the time of a tick bite is not recommended as it would likely be misleading 3

3. Administering prophylaxis when criteria are not met: This exposes patients to unnecessary antibiotics 1

4. Delayed prophylaxis: Prophylaxis becomes ineffective when given >72 hours after tick removal 1

5. Ignoring geographic considerations: Prophylaxis is only recommended in areas with ≥20% tick infection rates 1

Preventive Measures

In addition to considering prophylaxis, advise patients and families on preventive measures:

• Use EPA-registered tick repellents
• Wear protective clothing
• Perform regular tick checks after outdoor activities
• Remove attached ticks promptly using tweezers or forceps 4

Treatment if Lyme Disease Develops

If a patient develops symptoms of Lyme disease:

• For children ≥8 years: Doxycycline 100 mg twice daily for 10 days 1, 2
• For children <8 years: Amoxicillin is the preferred treatment for non-neurological manifestations 5

Recent evidence suggests doxycycline may be safer in children <8 years than previously thought, but amoxicillin remains the preferred treatment for this age group for non-neurological Lyme disease 5.