Lyme Disease
Lyme disease (Lyme borreliosis) is a spirochetal infection caused by bacteria of the Borrelia burgdorferi sensu lato complex and transmitted through the bite of Ixodes ticks. Its hallmark is an expanding bull's-eye rash at the bite site (erythema migrans). If the infection is not recognized and treated early with antibiotics, the spirochetes spread through the bloodstream and can cause serious complications in the nervous system, heart, joints and skin, some of them chronic.
At Haute-Derma, managing Lyme disease starts with a sharp clinical eye for the earliest skin signs. We follow the standard two-tier serologic testing protocol and use a complete course of antibiotics to minimize the risk of long-term, body-wide complications.
Pathogenesis and Transmission
Causative Organism and Vector
- Pathogen: the spirochetes Borrelia burgdorferi (mainly in North America), Borrelia afzelii and Borrelia garinii (common in Europe and Asia).
- Vector: hard ticks of the genus Ixodes (Ixodes scapularis, Ixodes ricinus). Nymphs, which are tiny (about the size of a sesame seed), are responsible for most human infections.
- How it spreads: the tick attaches to the skin and feeds on blood. It generally has to stay attached and feed for at least 36–48 hours before Borrelia moves from the tick's salivary glands into the host's bloodstream.
Immune Response and Skin Pathogenesis
- Invasion and spread: once in the skin, the spirochetes migrate outward through the dermis, provoking inflammation around blood vessels and drawing T cells and macrophages to the advancing edge. The result is an enlarging red patch with a paler center — the bull's-eye pattern.
- Immune evasion: Borrelia can block the complement pathway and keeps changing its surface antigens (VlsE and outer surface proteins). This lets it slip past the immune system and travel via the blood to the joints, heart and central nervous system.
Clinical Features by Stage
Early Localized Stage (Days 3–30 After the Bite):
- Erythema migrans (EM): seen in 70%–80% of patients, 3–30 days after the tick bite. It begins as a red papule at the bite site and expands outward (more than 5 cm across, sometimes up to 30 cm). The center gradually fades, producing the typical bull's-eye appearance. The rash is painless and either not itchy or only mildly so.
- Flu-like symptoms: low-grade fever, chills, fatigue, headache, muscle aches, scattered joint pain and local lymph node swelling.
Early Disseminated Stage (Weeks to Months):
- Secondary skin lesions: multiple smaller EM lesions appear across the body as the spirochetes spread through the blood.
- Neurologic involvement (neuroborreliosis): one- or two-sided facial nerve palsy (Bell's palsy, cranial nerve VII), lymphocytic meningitis and polyneuritis.
- Cardiac involvement (Lyme carditis): conduction disturbances and atrioventricular (AV) block, which can cause fainting and chest pain.
Late Disseminated Stage (Months to Years):
- Lyme arthritis: recurring, long-lasting swelling and pain in large joints, especially the knee.
- Borrelial lymphocytoma: a benign reddish-purple papule or nodule on the earlobe, nipple or armpit.
- Acrodermatitis chronica atrophicans (ACA): mostly seen in Europe (B. afzelii). The skin of the hands and feet turns reddish-purple, swells at first and then becomes atrophic, ending up as thin as cigarette paper.
Differential Diagnosis of Annular and Target-Like Rashes
| Lyme Disease (Erythema Migrans) | Tinea Corporis (Body Ringworm) | Erythema Multiforme |
|---|---|---|
| Spirochete Borrelia burgdorferi | Dermatophyte fungi | Drug reaction / herpes simplex |
| Expands quickly (> 5 cm, up to 30 cm) | Smaller, spreads slowly | Small, fixed target lesions |
| Flat edge, no scale, pale center | Raised edge with fine scale / blisters | Target shape with three color zones |
| Usually not itchy or mildly itchy | Very itchy, burning | Mild burning, moderate itch |
| Flu-like fever, joint pain, fatigue | None | Possible fever, mucosal lesions |
Our Diagnostic Approach at Haute-Derma
Exposure and Bite History:
- We ask about picnics, hiking or gardening in wooded, brushy areas where ticks are common.
- We confirm whether a tick was found attached to the skin (if the patient noticed one).
Skin Examination:
- We look for the expanding erythema migrans rash. Clinical note: in an endemic area, a typical EM rash is enough to diagnose Lyme disease and start treatment right away, without waiting for lab results.
Two-Tier Serologic Testing:
- Step 1: an ELISA (or IFA) measuring IgM/IgG antibodies against Borrelia.
- Step 2: if step 1 is positive or equivocal, a Western blot (immunoblot) is done to confirm.
- Note: in the first 2–4 weeks after infection (the EM stage), serology can be falsely negative because the body has not yet made enough antibodies.
Treatment and Recovery Plan at Haute-Derma
Antibiotic Treatment for Early (Acute) Disease
- Doxycycline (first choice):
- Dose: 100 mg by mouth twice daily.
- Duration: 10–14 days.
- Advantage: clears Borrelia and also covers Anaplasma phagocytophilum (the cause of anaplasmosis, which is often transmitted by the same tick bite).
- Amoxicillin:
- Dose: 500 mg three times daily for 14 days.
- Used for: pregnant or breastfeeding women and children under 8 (in whom doxycycline is contraindicated).
- Cefuroxime axetil:
- Dose: 500 mg twice daily for 14 days (an alternative for patients allergic to penicillins or tetracyclines).
Treating Disseminated Disease and Complications
- Lyme meningitis / heart block: intravenous ceftriaxone (2 g/day) for 14–28 days.
Prevention and What to Do After a Tick Bite
- Removing the tick: grip the tick's mouthparts as close to the skin as possible with fine-tipped tweezers and pull straight up with steady pressure. Do not twist, and do not apply heat, alcohol or kerosene to the tick — this can make it release bacteria-laden saliva into the skin.
- Antibiotic prophylaxis: a single 200 mg dose of doxycycline within 72 hours of removal, if the tick is an Ixodes species that had been feeding for more than 36 hours in an endemic area.
