Erythema Migrans Differential Scoring (Lyme Disease)

Evaluates probability of erythema migrans being due to Lyme disease based on lesion characteristics: expanding erythema, central clearing (bull's-eye pattern), tick exposure history, lesion size ≥5 cm, and days since tick bite (3–30 days). Guides empiric antibiotic initiation.

Weight
Height
Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.
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How It Works

Evaluates probability of erythema migrans being due to Lyme disease based on lesion characteristics: expanding erythema, central clearing (bull's-eye pattern), tick exposure history, lesion size ≥5 cm, and days since tick bite (3–30 days). Guides empiric antibiotic initiation

Each component has a specific meaning:

  • Lesion characteristics: expanding erythema — The lesion characteristics: expanding erythema recorded for the scenario being assessed.
  • Central clearing — The central clearing recorded for the scenario being assessed.
  • Tick exposure history — The tick exposure history recorded for the scenario being assessed.
  • Lesion size ≥5 cm — The lesion size ≥5 cm recorded for the scenario being assessed.
  • Days since tick bite — The days since tick bite recorded for the scenario being assessed.

Note: Interpret the erythema migrans score result against the thresholds and context described above.

How to Use

Enter the lesion characteristics: expanding erythema, central clearing, tick exposure history, lesion size ≥5 cm, days since tick bite for the scenario you are assessing. Evaluates probability of erythema migrans being due to Lyme disease based on lesion characteristics: expanding erythema, central clearing (bull's-eye pattern), tick exposure history, lesion size ≥5 cm, and days since tick bite (3–30 days). Guides empiric antibiotic initiation. Use the erythema migrans score result to inform your calculation.

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Frequently Asked Questions