Should a person with a deer tick (Ixodes spp.) attachment of less than 24 hours, confirmed to carry Borrelia burgdorferi, the causative agent of Lyme disease, be treated with antibiotics if they are asymptomatic?

From the Guidelines

Prophylactic antibiotic treatment is not recommended for individuals with a deer tick bite carrying Borrelia burgdorferi if the tick was attached for less than 24 hours and the person is symptom-free. According to the 2020 guidelines for the prevention, diagnosis, and treatment of Lyme disease by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR) 1, a tick bite is considered high-risk only if it meets specific criteria, including attachment for ≥36 hours. Since the tick was attached for less than 24 hours, the risk of Lyme disease transmission is low.

Key considerations for this decision include:

• The tick's attachment time: less than 24 hours is considered low-risk for disease transmission
• The person's symptom status: currently symptom-free
• The potential adverse effects of antibiotics, including allergic reactions, gastrointestinal issues, and contribution to antibiotic resistance

Instead of antibiotics, careful monitoring for symptoms over the next 30 days is advised, including:

• Characteristic expanding bull's-eye rash (erythema migrans)
• Fever
• Fatigue
• Headache
• Muscle and joint aches
• Swollen lymph nodes If symptoms develop, treatment with doxycycline or amoxicillin should be initiated promptly, as recommended by the guidelines 1. This approach balances the low risk of disease transmission against the potential adverse effects of antibiotics.

From the Research

Treatment of Lyme Disease

• The decision to treat a person with antibiotics after a deer tick bite depends on various factors, including the duration of tick attachment and the presence of symptoms 2, 3, 4.
• According to a study published in the American Family Physician, transmission of Borrelia burgdorferi typically requires a minimum of 24 to 48 hours of tick attachment 2.
• A study published in The New England Journal of Medicine found that the risk of infection with B. burgdorferi after a recognized deer-tick bite is low, and prophylactic antimicrobial treatment is not routinely indicated 3.
• Another study published in the Journal of the American Academy of Dermatology found that the risk of infection after a deer tick bite appears to be low, particularly if the tick has been attached for less than 24 hours 4.

Antibiotic Treatment

• The recommended treatment for Lyme disease includes doxycycline, amoxicillin, and ceftriaxone 2, 5, 6.
• A study published in Polski Merkuriusz Lekarski found that azithromycin may be an effective alternative to doxycycline, especially in the first stage of infection 6.
• However, the use of antibiotics should be guided by clinical evaluation and serologic testing, and treatment should be individualized based on the stage of disease and patient factors 5.

Risk of Infection

• The risk of acquiring Lyme disease is low in a person who has a deer tick bite, especially if the tick has been attached for less than 24 hours 2, 3, 4.
• A study published in The New England Journal of Medicine found that the risk of infection with B. burgdorferi in the placebo-treated subjects was 1.2 percent, which was not significantly different from the risk in the amoxicillin-treated subjects 3.
• Therefore, in the absence of symptoms, antibiotic treatment may not be necessary for individuals who have been bitten by a deer tick that has been attached for less than 24 hours 2, 3, 4.