Tick-borne illness (Lyme disease)MANAGEMENT

INFECTIOUS DISEASE PRESENTATIONS · 12 SECTIONS

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685 items

☷ Legend

01Approach to the Critical Patient/attcp40

Immediate stabilization

›Time-critical threats

›Airway compromise

›Escalate to resuscitation bay for altered mental status with airway risk

›If seizure, initiate seizure management protocol

›Shock physiology

›If hypotension with fever, initiate sepsis pathway

›If suspected anaphylaxis, initiate anaphylaxis protocol

›Malignant dysrhythmia

›If syncope or chest pain with bradycardia, immediate ECG and continuous monitoring

›If high-grade AV block, transcutaneous pacing readiness

›Monitoring and access

›Cardiac monitoring

›Continuous telemetry for palpitations, syncope, chest pain, dyspnea

›Repeat ECG for evolving conduction delay

›Vitals trend

›Temperature trend for persistent fever

›Orthostatic vitals for presyncope

›IV access

›Two large-bore IV for unstable patients

›Consider intraosseous access if unable to obtain IV and unstable

›Early escalation triggers

›Neuroborreliosis concern

›If meningismus or focal deficit, emergent neurology consultation

›If encephalopathy, ICU-level evaluation

›Lyme carditis concern

›If PR interval >= 300 ms, admit with telemetry

›If second-degree Mobitz II or third-degree AV block, urgent cardiology consultation

›Severe systemic illness in endemic setting

›If thrombocytopenia with hemolysis pattern, urgent babesiosis evaluation

›If high fever with leukopenia, urgent anaplasmosis or ehrlichiosis evaluation

Key concepts

›Clinical framework

›Tick-borne illness spectrum

›Borrelia burgdorferi infection with staged manifestations

›Common coinfections in Ixodes exposure

›High-value diagnostic pivot

›Erythema migrans with compatible exposure is a clinical diagnosis

›Two-tier serology has low sensitivity in early localized disease

›Time dependence

›Tick attachment duration correlates with transmission risk

›Early therapy reduces dissemination and late sequelae

02History/hx87

Exposure and timeline

›Exposure risk profile

›Geography and season

›Residence or travel in Lyme endemic region

›Outdoor activity in wooded or grassy areas

›Tick encounter details

›Known tick bite

›Tick attachment duration estimate

›Tick engorgement

›Prophylaxis and removal

›Tick removal method and timing

›Prior post-exposure doxycycline dose

›Symptom chronology

›Early localized window

›Rash onset timing after bite

›Flu-like symptoms without prominent respiratory features

›Early disseminated window

›Multiple rashes

›Facial weakness onset timing

›Palpitations, presyncope, syncope

›Late disease window

›Intermittent or persistent large-joint swelling

›Prior untreated episodes

Symptom inventory by system

›Dermatologic

›Expanding erythematous rash

›Single lesion

›Multiple lesions

›Pruritus or pain severity

›Minimal symptoms typical

›Marked pain suggests alternative diagnosis

›Neurologic

›Headache

›Severe or persistent features

›Associated photophobia

›Meningeal features

›Neck stiffness

›Nausea or vomiting

›Cranial neuropathy

›Facial droop

›Diplopia

›Radicular pain

›Shooting limb pain

›Sensory changes

›Cardiac

›Palpitations

›Episodic tachycardia sensation

›Irregular heartbeat sensation

›Presyncope or syncope

›Exertional component

›Resting component

›Dyspnea or chest pain

›Orthopnea

›Pleuritic features

›Musculoskeletal

›Arthralgia

›Migratory pain

›Myalgia

›Arthritis pattern

›Knee swelling

›Other large-joint swelling

›Systemic

›Fever pattern

›High spiking fever suggests coinfection

›Night sweats

›Constitutional symptoms

›Fatigue

›Malaise

Risk modifiers and pitfalls

›Host factors

›Immunocompromised state

›Asplenia risk for severe babesiosis

›B-cell depleting therapy

›Pregnancy status

›Gestational age

›Prenatal care access

›Alternative explanations

›Recent cellulitis or abscess near rash site

›Purulence history

›Rapid onset within 24 to 48 hours

›Viral syndrome exposure

›Household contacts

›Prominent upper respiratory symptoms

›Prior Lyme testing and treatment

›Previous two-tier results

›Positive IgG suggests prior exposure or later stage

›Isolated IgM beyond early window increases false positive risk

›Prior antibiotics

›Doxycycline course length

›Amoxicillin course length

03Physical Exam/exam62

General and vitals

›Physiologic state

›Fever

›Persistent high fever suggests coinfection

›Afebrile does not exclude Lyme

›Hemodynamics

›Hypotension suggests sepsis or alternative diagnosis

›Bradycardia suggests conduction disease

›Respiratory status

›Hypoxemia suggests alternative pulmonary process

›Tachypnea suggests systemic severity

Skin and soft tissue

›Rash characterization

›Erythema migrans pattern

›Expanding annular erythema

›Central clearing may be absent

›Alternative rash patterns

›Vesicular dermatomal rash suggests herpes zoster

›Petechiae suggests rickettsial illness

›Lesion metrics

›Diameter estimate

›Warmth and tenderness severity

›Bite site evaluation

›Tick remnants

›Retained mouthparts

›Local inflammation without infection

›Cellulitis features

›Diffuse warmth with tenderness

›Lymphangitic streaking

Neurologic and ENT

›Cranial nerve exam

›Facial nerve function

›Upper and lower facial weakness

›Bilateral facial weakness

›Ocular findings

›Extraocular movements

›Papilledema concern

›Meningeal signs

›Nuchal rigidity

›Kernig sign

›Brudzinski sign

›Mental status

›Delirium

›Lethargy

›Peripheral neurologic exam

›Motor function

›Focal weakness

›Gait instability

›Sensory function

›Dermatomal sensory loss

›Distal paresthesias

Cardiopulmonary

›Rhythm and conduction clues

›Bradycardia

›Irregular rhythm

›Pulse deficit variability

›Signs of heart failure

›Crackles

›Peripheral edema

›Perfusion assessment

›Capillary refill

›Delayed refill suggests shock state

›Normal refill does not exclude conduction disease

›Jugular venous pressure estimate

›Elevated suggests heart failure or tamponade physiology

›Normal does not exclude myocarditis

04Differential Diagnosis/ddx53

Tick-borne and vector-borne

›Alternative tick-borne infections

›Anaplasmosis (ICD-10 A79.82)

›High fever with leukopenia and thrombocytopenia

›Elevated transaminases pattern

›Babesiosis (ICD-10 B60.0)

›Hemolytic anemia pattern

›Dark urine history

›Ehrlichiosis (ICD-10 A79.82 or A79.89 depending coding)

›Fever with leukopenia and thrombocytopenia

›Rash less common in adults

›Rocky Mountain spotted fever (ICD-10 A77.0)

›Fever with headache

›Petechial rash including palms and soles

›Tick-borne relapsing fever (ICD-10 A68.1)

›Relapsing fever episodes

›Severe headache

›Other arthropod-associated syndromes

›West Nile virus infection (ICD-10 A92.3)

›Neuroinvasive features

›Tremor or movement disorder

›Powassan virus infection (ICD-10 A84.8)

›Encephalitis features

›Rapid progression

Non-tick mimics by presentation

›Rash predominant

›Cellulitis (ICD-10 L03)

›Tenderness disproportionate to EM

›Rapid progression within 24 to 48 hours

›Tinea corporis (ICD-10 B35.4)

›Scaly border

›Pruritus prominent

›Erythema multiforme (ICD-10 L51.9)

›Target lesions

›Mucosal involvement

›Neurologic predominant

›Viral meningitis (ICD-10 A87.9)

›CSF lymphocytic pleocytosis

›Enterovirus exposure

›Bacterial meningitis (ICD-10 G00.9)

›Toxic appearance

›Neutrophilic CSF pattern

›Bell palsy idiopathic (ICD-10 G51.0)

›Isolated unilateral facial palsy

›No systemic features

›Cardiac predominant

›Acute myocarditis non-Lyme (ICD-10 I40.9)

›Troponin elevation pattern

›Viral prodrome prominent

›Primary conduction disease (ICD-10 I44)

›Older age without exposure history

›Chronic progression

›Acute coronary syndrome (ICD-10 I21)

›Typical angina pattern

›Risk factor profile

05Laboratory Tests/lt47

Core labs by syndrome

›Baseline assessment set

›Complete blood count

›Leukopenia suggests anaplasmosis or ehrlichiosis

›Thrombocytopenia suggests anaplasmosis, ehrlichiosis, babesiosis, RMSF

›Electrolytes and renal function

›Dehydration assessment

›Renal dosing considerations

›Liver enzymes

›Transaminase elevation suggests anaplasmosis or ehrlichiosis

›Cholestatic pattern suggests alternative hepatobiliary disease

›Hemolysis and babesiosis set

›Hemoglobin and reticulocyte pattern

›Anemia with reticulocytosis suggests hemolysis

›Normal hemoglobin does not exclude early babesiosis

›Lactate dehydrogenase

›Elevated supports hemolysis

›Non-specific elevation caveat

›Haptoglobin

›Low supports hemolysis

›Acute phase effects caveat

›Total bilirubin

›Indirect predominance suggests hemolysis

›Direct predominance suggests hepatic process

Cardiac and inflammatory markers

›Carditis or myocarditis evaluation

›Troponin

›Elevation supports myocardial involvement

›Normal troponin does not exclude conduction-only carditis

›B-type natriuretic peptide or NT-proBNP

›Elevation supports heart failure physiology

›Interpretation limited by age and renal function

›Sepsis physiology adjuncts

›Lactate in mmol/L

›Elevated supports hypoperfusion physiology

›Normal does not exclude early sepsis

Cerebrospinal fluid studies when indicated

›Lumbar puncture panel

›Cell count and differential

›Lymphocytic pleocytosis supports viral or Lyme meningitis

›Neutrophilic predominance supports bacterial meningitis early caveat

›Protein

›Elevation common in neuroborreliosis

›Non-specific elevation caveat

›Glucose in mmol/L

›Normal glucose common in viral and Lyme meningitis

›Low glucose suggests bacterial, fungal, TB meningitis

›CSF Borrelia antibody index when available

›Supports intrathecal antibody production

›Availability varies by region

06Diagnostic Tests/dt82

Scoring Systems

›Clinical risk stratification

›No universally validated ED scoring tool for Lyme diagnosis

›Use exposure plus stage-based syndrome recognition

›Avoid overreliance on serology in early localized disease

›Suspicion of Lyme carditis syndrome screen

›Constitutional symptoms

›Palpitations, presyncope, syncope

›Known tick exposure or endemic travel

›ECG conduction severity anchor

›PR interval trend

›Presence of second-degree or third-degree AV block

›Stage-based diagnostic anchors

›Early localized

›Single erythema migrans with compatible exposure is sufficient for treatment

›Serology may be negative in first weeks

›Early disseminated

›Multiple erythema migrans

›Facial palsy with compatible exposure

›Carditis with AV block

›Late disease

›Intermittent or persistent large-joint arthritis

MRI

›Neuroimaging considerations

›MRI brain with and without contrast

›If focal neurologic deficits

›If concern for encephalitis or demyelinating mimic

›MRI spine with and without contrast

›If radiculopathy with objective neurologic deficits

›If myelitis concern

›Limitations

›Normal MRI does not exclude neuroborreliosis

›Findings are non-specific and overlap with other inflammatory disorders

›Acute neuro presentations

›Non-contrast CT head

›If new focal deficit to exclude hemorrhage or mass

›If altered mental status prior to lumbar puncture risk assessment

›CT angiography head and neck

›If stroke syndrome concern

›Lyme not typical primary cause of large-vessel occlusion

›Limitations

›CT does not diagnose Lyme

›Used to exclude alternative emergent pathology

›Avoid delay of antibiotics when clinical diagnosis is clear

Ultrasound (or US)

›Cardiac point-of-care ultrasound

›Global function estimate

›If dyspnea or chest pain with suspected myocarditis

›If hypotension with concern for cardiogenic shock

›Pericardial effusion screen

›If chest pain with hypotension

›If tachycardia with muffled heart sounds concern

›Joint ultrasound

›Effusion confirmation

›Large joint swelling to support inflammatory arthritis syndrome

›Aid in arthrocentesis planning

›Limitations

›Ultrasound does not confirm Lyme etiology

›Supports syndrome evaluation and procedural guidance

›Synovial fluid analysis required for septic arthritis exclusion

Serologic and microbiologic testing

›Lyme serology strategy

›Two-tier testing pathway

›First-tier EIA or ELISA

›Second-tier immunoblot or second EIA depending on algorithm

›Timing caveats

›Early localized disease false negative risk

›Antibodies may persist after prior infection and treatment

›Interpretation pitfalls

›Isolated IgM positivity outside early window increases false positive risk

›Clinical correlation required for all results

›Coinfection testing strategy

›Anaplasma or Ehrlichia PCR

›Highest yield early in illness

›Sensitivity decreases after doxycycline initiation

›Babesia evaluation

›Peripheral blood smear for parasites

›Babesia PCR for low parasitemia concern

›Synovial fluid evaluation for monoarthritis

›Arthrocentesis in hot swollen joint

›Cell count and differential

›Gram stain and culture

›Crystal analysis

›Lyme PCR in synovial fluid when available

›Supports Lyme arthritis

›Not a stand-alone rule-out test

07Disposition/dispo37

Level of care decisions

›Admission indications

›Cardiac conduction disease

›PR interval >= 300 ms

›Second-degree Mobitz II AV block

›Third-degree AV block

›Neuroborreliosis concern

›Meningitis features with dehydration or inability to tolerate oral meds

›Encephalopathy

›Progressive focal deficits

›Severe systemic illness

›Persistent high fever with cytopenias

›Hemolysis pattern or parasitemia concern

›ICU indications

›Unstable bradyarrhythmia

›Hemodynamic instability from AV block

›Need for temporary pacing

›Septic physiology

›Hypotension after fluids

›Elevated lactate with shock features

Discharge criteria and follow-up

›Safe outpatient management criteria

›Stable vitals

›No syncope

›No hypotension

›No high-risk neuro features

›No meningismus with toxicity

›No progressive focal deficits

›Reliable oral intake

›Tolerating oral antibiotics

›Pain controlled

›Follow-up planning

›Primary care follow-up

›Reassessment within 48 to 72 hours for persistent symptoms

›Review pending serology if obtained

›Specialty follow-up triggers

›Cardiology for any conduction abnormality

›Neurology for facial palsy or meningitis syndrome

›Infectious diseases for severe or refractory disease

08Treatment/t139

Tick removal and prevention

›Immediate tick management

›Proper removal technique

›Fine-tipped tweezers close to skin

›Steady upward traction

›Local care

›Soap and water cleansing

›Topical antiseptic use

›Post-exposure prophylaxis criteria

›Doxycycline prophylaxis eligibility

›Ixodes species likely

›Attachment duration >= 36 hours

›Prophylaxis within 72 hours of tick removal

›Local infection rate threshold consistent with endemic area policy

›Doxycycline prophylaxis regimen

›Doxycycline 200 mg PO once

›If age < 8 years, local guideline alignment required

›If pregnancy, avoid doxycycline prophylaxis and use shared decision-making

Early localized Lyme disease

›Erythema migrans treatment

›First-line oral options

›Doxycycline 100 mg PO twice daily

›Duration 10 days

›Avoid in pregnancy

›Amoxicillin 500 mg PO three times daily

›Duration 14 days

›Preferred in pregnancy

›Cefuroxime axetil 500 mg PO twice daily

›Duration 14 days

›Use for beta-lactam preference

›Symptom control

›Acetaminophen weight-appropriate dosing

›Max daily dose per local policy

›Hepatic disease precautions

›Ibuprofen weight-appropriate dosing

›Renal disease precautions

›GI bleeding risk precautions

›Evidence integration

›Erythema migrans is treated without waiting for serology

›Strong guideline consensus

›ACEP Level C alignment for clinical diagnosis priority in classic EM

Early disseminated Lyme disease

›Facial palsy without meningitis

›Oral doxycycline regimen

›Doxycycline 100 mg PO twice daily

›Duration 14 to 21 days

›Photosensitivity counseling

›Eye protection

›Lubricating drops

›Daytime use schedule

›Preservative-free option for frequent use

›Nighttime eye ointment

›Bedtime application

›Tape or eye shield if incomplete closure

›Corticosteroids

›Routine steroids not recommended when Lyme facial palsy suspected

›Potential for worse outcomes in some observational data

›Use shared decision-making if idiopathic Bell palsy remains primary diagnosis

›Lyme meningitis or radiculoneuritis

›IV options

›Ceftriaxone 2 g IV daily

›Duration 14 to 21 days

›Monitor for biliary sludge and diarrhea

›Cefotaxime 2 g IV every 8 hours

›Duration 14 to 21 days

›Use if ceftriaxone unavailable

›Oral option in selected cases

›Doxycycline 100 mg PO twice daily

›Duration 14 to 21 days

›Use when clinically stable and able to tolerate oral therapy per local guidance

›Adjunctive care

›Analgesia and antiemetics as needed

›Avoid oversedation

›Hydration support

Lyme carditis

›Cardiac monitoring and pacing readiness

›Telemetry

›Continuous monitoring for any AV block

›Serial ECG for PR interval trend

›Temporary pacing pathway

›If symptomatic high-grade AV block, initiate transcutaneous pacing

›Prepare transvenous pacing if persistent

›Cardiology consultation emergent

›Class I pacing indication for unstable bradycardia physiology

›Syncope or hypotension attributable to bradyarrhythmia

›Failure of medical temporizing measures

›Antibiotic therapy selection

›Mild carditis without high-grade block

›Doxycycline 100 mg PO twice daily

›Duration 14 to 21 days

›Consider admission based on PR interval and symptoms

›Severe carditis or high-grade block

›Ceftriaxone 2 g IV daily

›Duration 14 to 21 days

›Step-down to oral therapy when conduction improves

›Avoidance and precautions

›AV nodal blockers

›Avoid beta-blockers and non-dihydropyridine calcium channel blockers in high-grade AV block

›Avoid digoxin in unstable conduction disease

Lyme arthritis

›Initial oral therapy

›Doxycycline 100 mg PO twice daily

›Duration 28 days

›Avoid in pregnancy

›Amoxicillin 500 mg PO three times daily

›Duration 28 days

›Pregnancy preferred option

›Cefuroxime axetil 500 mg PO twice daily

›Duration 28 days

›Use for intolerance to other agents

›Persistent arthritis after first course

›Reassessment

›Ensure septic arthritis excluded

›Consider repeat serology context and synovial studies

›Second antibiotic course strategy

›Repeat oral course in selected cases

›IV ceftriaxone 2 g IV daily for refractory cases per specialist guidance

›Post-infectious inflammatory arthritis

›Avoid prolonged antibiotics without evidence of active infection

›Consider rheumatology referral

›NSAID symptom control with precautions

Coinfection directed therapy

›Anaplasmosis or ehrlichiosis suspected

›Doxycycline 100 mg PO or IV twice daily

›Duration 10 to 14 days

›Initiate immediately when strongly suspected

›Pediatrics dosing

›Doxycycline 2.2 mg/kg per dose twice daily

›Max 100 mg per dose

›Use regardless of age when clinically indicated

›Babesiosis suspected or confirmed

›Outpatient mild to moderate disease

›Atovaquone 750 mg PO twice daily

›Duration 7 to 10 days

›Take with fatty food to improve absorption

›Azithromycin 500 mg PO day 1 then 250 mg PO daily

›Duration 7 to 10 days

›QT prolongation risk assessment

›Severe disease or immunocompromised

›Clindamycin plus quinine regimen per specialist guidance

›High adverse effect burden

›Consider ICU monitoring

›Exchange transfusion consideration for high parasitemia

›Hematology consultation

›Thresholds per local protocol

09Special Populations/sp41

Pregnancy

›Diagnostic and management adjustments

›Antibiotic selection

›Amoxicillin preferred for erythema migrans

›Cefuroxime acceptable alternative

›Avoidance

›Avoid doxycycline when possible

›Avoid unnecessary imaging with ionizing radiation

›Maternal and fetal considerations

›Obstetric consultation for systemic illness

›Fetal monitoring based on gestational age and maternal stability

Geriatric

›Age-related risks

›Higher baseline conduction disease prevalence

›Lower threshold for admission with PR prolongation

›Medication interaction review

›Atypical presentations

›Less prominent fever response

›Baseline cognitive impairment masking encephalopathy

›Medication considerations

›Renal function impact

›Dose adjustments for some agents

›Hydration monitoring

›Polypharmacy

›QT prolongation risk with macrolides

›Anticoagulation bleeding risk with NSAIDs

Pediatrics

›Presentation differences

›Higher facial palsy proportion in some cohorts

›Eye protection emphasis

›School safety counseling

›Arthritis patterns

›Knee effusion common

›Septic arthritis exclusion priority

›Weight-based dosing

›Amoxicillin for erythema migrans

›50 mg/kg per day divided three times daily

›Max adult dosing cap

›Cefuroxime axetil for erythema migrans

›30 mg/kg per day divided twice daily

›Max adult dosing cap

›Ceftriaxone for neuroborreliosis

›50 to 75 mg/kg IV daily

›Max 2 g daily

10Background/b48

Epidemiology

›Disease distribution

›Ixodes tick geographic overlap

›Highest incidence in endemic regions

›Risk increases in spring through fall

›Exposure settings

›Wooded and brushy areas

›Leaf litter environments

›Transmission features

›Attachment duration effect

›Risk increases with prolonged attachment

›Prompt removal reduces risk

›Coinfection reality

›Single tick may transmit multiple pathogens

›Persistent high fever suggests coinfection more than isolated Lyme

Pathophysiology

›Staging model

›Early localized infection

›Spirochete proliferation at bite site

›Erythema migrans as inflammatory response

›Early disseminated infection

›Hematogenous spread

›Neural and cardiac tissue involvement

›Late infection

›Immune-mediated synovitis

›Persistent inflammation after bacterial clearance in some patients

›Symptom mechanisms

›Carditis

›Inflammation of conduction system

›Fluctuating AV block severity

›Neuroborreliosis

›Lymphocytic meningitis

›Cranial neuritis and radiculitis patterns

Therapeutic Considerations

›Antibiotic principles

›Early therapy benefit

›Reduced progression to disseminated disease

›Reduced duration of symptoms

›Route selection by syndrome

›Oral therapy for uncomplicated early localized disease

›IV therapy for severe carditis and neuroborreliosis

›Duration principles

›Shorter regimens effective for erythema migrans

›Longer regimens for arthritis due to tissue penetration and inflammatory burden

›Post-treatment symptoms

›Persistent fatigue and pain after treatment can occur

›Not an indication for indefinite antibiotics

›Functional support and follow-up planning

›Jarisch-Herxheimer-like reactions

›Transient symptom worsening after antibiotics

›Supportive care and reassurance when mild

11Patient Discharge Instructions/pdi25

copy discharge instructions

›Discharge plan for suspected or confirmed Lyme disease

›Antibiotics

›Take exactly as prescribed

›Do not stop early even if improved

›Symptom expectations

›Fever and aches should improve over several days

›Rash may take longer to fade

›Tick prevention

›Daily skin checks after outdoor exposure

›Shower soon after outdoor activity

›Permethrin-treated clothing and DEET use per label

›Return to ED now for red flags

›Fainting or near-fainting

›Chest pain or trouble breathing

›New palpitations or very slow heart rate symptoms

›Severe headache with neck stiffness

›Confusion or new weakness

›New facial droop or trouble closing an eye

›Persistent high fever or shaking chills

›Dark urine or yellowing of eyes

›Rapidly spreading painful skin redness

›Follow-up

›Primary care visit within 2 to 3 days if not improving

›Cardiology follow-up if any ECG abnormality was found

›Neurology follow-up if facial palsy or meningitis symptoms occurred

12References/r24

Guidelines and high-quality sources

›Core guideline set

›IDSA AAN ACR 2020 Lyme disease clinical practice guideline

›Erythema migrans as clinical diagnosis and immediate treatment recommendation

›Antibiotic selection and duration recommendations by syndrome

›CDC Lyme disease clinical resources

›Two-tier testing principles and timing limitations

›Tick removal and prophylaxis criteria summary

›Public Health Agency of Canada Lyme disease resources

›Canadian endemic region framing and prevention guidance

›Testing and reporting considerations

›Evidence levels mapping notes

›Many Lyme recommendations derive from infectious diseases society guidance rather than ACEP levels

›ACEP Level C alignment used for ED-practice consensus items

›Class I or IIa framing reserved for pacing and unstable bradycardia pathways consistent with cardiology standards

›Cardiac conduction management references

›ACC AHA bradycardia and pacing guideline principles for unstable high-grade AV block

›Telemetry and temporary pacing for symptomatic high-grade block

›Diagnostic performance and pitfalls references

›Two-tier serology sensitivity is lower in early localized infection

›False negative risk in first weeks

›Improved sensitivity later in disease

›IgM false positives increase outside early window

›Avoid isolated IgM interpretation without compatible timing

›Correlate with exposure and syndrome

Evidence & Review

Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.