What is the recommended approach for a Lyme disease workup and treatment?

Recommended Approach for Lyme Disease Workup and Treatment

Diagnosis

Erythema migrans is the only manifestation of Lyme disease that allows clinical diagnosis without laboratory confirmation, and patients with this presentation should receive immediate oral antibiotic treatment without waiting for serologic testing results. 1

Clinical Diagnosis

• Erythema migrans typically appears 3-30 days after tick bite
• Usually >5 cm in diameter
• May have homogeneous appearance or central clearing with target-like appearance
• Not typically pruritic or scaly unless fading or treated with topical steroids
• May have vesicles or pustules at the center in ~5% of cases
• Often occurs at unusual sites for bacterial cellulitis

Differentiating from Tick Bite Hypersensitivity

• Hypersensitivity reactions are usually <5 cm and disappear within 24-48 hours
• True erythema migrans increases in size over time
• Marking borders with ink and observing for 1-2 days can help differentiate

Laboratory Testing

• For typical erythema migrans in endemic areas: no laboratory testing needed
• Serologic testing is insensitive in early disease (first 2 weeks)
• If initial testing is negative but suspicion remains high: repeat testing 2-3 weeks later
• Two-tiered serologic testing recommended when clinical presentation is unclear or for later stages:
  1. Initial screening with ELISA or indirect fluorescent antibody test
  2. Confirmation with Western blot test if ELISA is positive or equivocal

Treatment

Early Localized Disease (Erythema Migrans)

First-line treatments for adults:

• Doxycycline 100 mg twice daily for 10 days
• Amoxicillin 500 mg three times daily for 14 days
• Cefuroxime axetil 500 mg twice daily for 14 days

First-line treatments for children:

• Amoxicillin: 50 mg/kg/day in 3 divided doses (maximum 500 mg per dose) for 14 days
• Cefuroxime axetil: 30 mg/kg/day in 2 divided doses (maximum 500 mg per dose) for 14 days
• Doxycycline: 4 mg/kg/day in 2 divided doses (maximum 100 mg per dose) for children ≥8 years for 10 days

Neurologic Manifestations

• Meningitis or radiculopathy: IV ceftriaxone 2g daily for 14 days (range 10-28 days)
• Facial nerve palsy without CSF abnormalities: Oral regimen as for erythema migrans for 14 days
• Facial nerve palsy with CSF abnormalities: Treatment as for meningitis

Arthritis

• Initial treatment: Same oral regimens as for erythema migrans but for 28 days
• Arthritis that has failed to improve or worsened: IV ceftriaxone 2g daily for 2-4 weeks

Prophylaxis

Prophylaxis is recommended only for high-risk tick bites meeting ALL criteria:

• Identified Ixodes spp. vector tick
• Tick attached for ≥36 hours
• Prophylaxis started within 72 hours of tick removal
• Local infection rate of ticks with B. burgdorferi ≥20%

Prophylactic regimen:

• Adults: Single dose of doxycycline 200 mg
• Children ≥8 years: Single dose of doxycycline 4.4 mg/kg (maximum 200 mg)

Common Pitfalls to Avoid

1. Relying on serologic testing for early disease diagnosis

   • Antibody tests are often negative in the first 2 weeks
   • Treat erythema migrans based on clinical appearance without waiting for test results

2. Inappropriate prophylaxis

   • Only truly high-risk tick bites meeting all criteria should receive prophylaxis
   • Use "wait and watch" approach for low or equivocal risk bites

3. Misinterpreting persistent symptoms

   • Post-Lyme disease syndrome does not respond to additional antibiotic therapy
   • Extended antibiotic courses beyond recommended durations are not supported by evidence

4. Confusing similar conditions with Lyme disease

   • Southern Tick-Associated Rash Illness (STARI) can mimic erythema migrans
   • Treat as Lyme disease if distinction cannot be made

5. Inappropriate testing

   • Routine testing for Lyme disease is not recommended for patients with psychiatric illness, amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, dementia, or new-onset seizures

6. Using first-generation cephalosporins

   • These are ineffective against Borrelia burgdorferi

7. Attributing non-specific symptoms to Lyme disease without evidence

   • This can lead to unnecessary antibiotic treatment

Recent research has identified piperacillin as a potential alternative treatment that may be effective at lower doses than traditional antibiotics, but this is still experimental and not yet incorporated into clinical guidelines 2.