How should doxycycline be used in children after a tick bite? - briefly
Give a single dose of doxycycline at 4 mg per kilogram of body weight (up to a maximum of 200 mg) as soon as possible, preferably within 72 hours of the bite, for children of any age. If a tetracycline allergy is present, substitute amoxicillin.
How should doxycycline be used in children after a tick bite? - in detail
Doxycycline is the preferred antimicrobial for preventing and treating early Lyme disease in pediatric patients who have been bitten by a tick that may carry Borrelia burgdorferi. The drug should be initiated as soon as possible after the bite, ideally within 72 hours, because early therapy reduces the risk of disseminated infection.
Dosage and administration
- Children weighing ≥ 15 kg: 4 mg/kg (maximum 200 mg) taken orally twice daily.
- Children weighing < 15 kg: 2.2 mg/kg (maximum 100 mg) taken orally twice daily.
- Treatment duration: 10 days for prophylaxis; 21 days for confirmed early Lyme disease.
- Tablets should be swallowed whole with a full glass of water; chewable or liquid formulations are acceptable for younger children who cannot swallow tablets.
- Food does not significantly affect absorption; a light meal may reduce gastrointestinal irritation.
Timing relative to exposure
- Initiate therapy within three days of the bite if the tick was attached ≥ 36 hours, the region is endemic, and the tick is identified as an Ixodes species.
- If the bite occurred more than 72 hours ago, doxycycline may still be prescribed if early Lyme disease symptoms (e.g., erythema migrans) are present.
Contraindications and precautions
- Avoid use in infants younger than eight weeks because of the risk of permanent tooth discoloration and enamel hypoplasia.
- Do not prescribe to children with a known hypersensitivity to tetracyclines.
- Caution in patients with hepatic or renal impairment; dose adjustment may be required.
- Monitor for photosensitivity; advise protective clothing and sunscreen during outdoor activities.
Adverse effects
- Common: nausea, vomiting, abdominal discomfort.
- Less common: photosensitivity, mild elevations in liver enzymes.
- Rare: severe allergic reactions, intracranial hypertension.
- If vomiting occurs within one hour of dosing, repeat the dose; otherwise, skip and continue the schedule.
Follow‑up
- Re‑evaluate the child after completing therapy to confirm resolution of rash or systemic symptoms.
- Document the tick species, attachment duration, and geographic location to support epidemiologic tracking.
Adhering to the weight‑based dosing schedule, initiating treatment promptly, and completing the full course are essential for effective management of tick‑borne infection in children.