# Lyme Disease and Borreliosis > Lyme disease and borreliosis for NEET-PG Medicine: erythema migrans, stages of disease, Ixodes tick vectors and doxycycline as first-line treatment. - Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/lyme-disease-and-borreliosis - Exam / course: NEET-PG · Subject: Medicine - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-14 - Last updated: 2026-10-14 - Reference basis: Harrison's Principles of Internal Medicine; Davidson's Principles and Practice of Medicine; Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases - How to cite: "Lyme Disease and Borreliosis", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/lyme-disease-and-borreliosis ## Direct answer Lyme disease is a tick-borne multisystem infection caused by Borrelia burgdorferi, transmitted by Ixodes ticks, and it progresses through early localised, early disseminated and late stages. Erythema migrans, an expanding annular rash with central clearing, is the characteristic early lesion, and doxycycline is the usual first-line treatment in adults. ## What you must remember - **Organism:** Borrelia burgdorferi is a spirochete transmitted by Ixodes ticks, with Ixodes scapularis and Ixodes ricinus as principal vectors in eastern North America and Europe (Ixodes pacificus on the US west coast). - **Erythema migrans:** An expanding annular rash with central clearing, the hallmark of early localised disease. - **Early disseminated disease:** Multiple skin lesions, facial nerve palsy, carditis with heart block and lymphocytic meningitis. - **Late disease:** Oligoarthritis, classically of the knee, along with neurological involvement and chronic skin change in Europe. - **First-line treatment:** Doxycycline is used for adults with early disease, usually for about ten days. - **Alternatives:** Amoxicillin or cefuroxime are used for children and pregnant women, because tetracyclines are avoided there. - **Tick removal:** Prompt removal of attached ticks reduces transmission, since infection usually needs prolonged attachment. - **Indian relevance:** Lyme disease is rarely reported in India, so it is tested mainly as a classic textbook entity. ## Staging Lyme disease and choosing treatment A 30-year-old hiker from an endemic region develops an expanding annular rash with central clearing on the thigh, about ten days after a walk through woodland. The rash alone supports the diagnosis, and serology is not needed to start treatment. 1. **Take the exposure history:** Ask about walking in woodland or grassland, since tick exposure defines the risk period. 2. **Recognise erythema migrans:** An expanding annular rash with central clearing is the characteristic lesion of early localised disease. 3. **Look for disseminated signs:** Check for multiple skin lesions, facial nerve palsy, arrhythmia or meningitis, which mark early disseminated disease. 4. **Check for late disease:** Look for oligoarthritis, typically of the knee, or neurological involvement, which appear weeks to months after infection. 5. **Choose the antibiotic:** Use doxycycline for most adults with early disease, with amoxicillin or cefuroxime for children and pregnant women. 6. **Use serology carefully:** Serology is often negative early, so it supports rather than replaces the clinical diagnosis, and two-tier testing is used where needed. ## Where the exam tries to catch you Most traps involve the timing of serology, the choice of antibiotic in special groups and the recognition of disseminated signs. - **Trap:** Waiting for serology before treating early Lyme disease. — **Correct:** Serology is often negative early, so erythema migrans is treated on clinical grounds. - **Trap:** Prescribing doxycycline to a pregnant woman or a young child. — **Correct:** Amoxicillin or cefuroxime is used, because tetracyclines are traditionally avoided in pregnancy and young children (recent US guidance allows short doxycycline courses in children). - **Trap:** Ignoring facial nerve palsy in a patient with a tick bite history. — **Correct:** Facial palsy is a classic early disseminated feature, so Lyme disease should be considered in endemic exposure. - **Trap:** Dismissing erythema migrans as an allergic rash. — **Correct:** The expanding annular lesion with central clearing is the characteristic sign that prompts treatment. ## Frequently asked questions ### What is the characteristic skin lesion of early Lyme disease? Erythema migrans is the characteristic skin lesion of early Lyme disease, an expanding annular rash with central clearing that appears at the site of a tick bite. It is a clinical diagnosis and usually appears within days to a few weeks of the bite. ### Which tick transmits Borrelia burgdorferi? Ixodes ticks transmit Borrelia burgdorferi, with Ixodes scapularis in North America and Ixodes ricinus in Europe as the principal vectors. Transmission usually requires the tick to remain attached for a prolonged period. ### Which antibiotic is used for early Lyme disease in adults? Doxycycline is the first-line antibiotic for early localised Lyme disease in adults, usually given for about ten days. Amoxicillin or cefuroxime are used as alternatives, especially in children and pregnant women. ### What is Bannwarth syndrome? Bannwarth syndrome is a neurological form of Lyme disease seen in Europe, presenting with lymphocytic meningitis and painful radiculoneuritis. It is a disseminated form of neuroborreliosis and needs antibiotic treatment. ### Why does serology often fail in early Lyme disease? Antibody responses take several weeks to develop, so serology is often negative during the early erythema migrans stage. Early Lyme disease is therefore diagnosed clinically, and serology is reserved for later or uncertain presentations.