13.4 Lyme Borreliosis, Rickettsioses & Other Zoonotic and Travel-Related Skin Infections
Key Takeaways
- Erythema migrans is an expanding red patch of at least 5 cm appearing days to weeks after an Ixodes tick bite, and it is diagnosed clinically without serology.
- European guidelines treat erythema migrans with doxycycline for about 10 to 14 days, or amoxicillin in children and pregnancy, and treat acrodermatitis chronica atrophicans for about 21 to 28 days.
- Acrodermatitis chronica atrophicans is a late Lyme manifestation, usually caused by Borrelia afzelii, with violaceous then atrophic skin on the extensor limbs of older adults and high IgG antibody titres.
- Mediterranean spotted fever, caused by Rickettsia conorii, presents with fever, a black eschar (tache noire) at the tick bite site, and a maculopapular rash including the palms and soles.
- Cutaneous larva migrans, caused by animal hookworm larvae after walking barefoot on beaches, produces itchy serpiginous tracks and is treated with oral ivermectin or albendazole.
Last updated: September 2026
13.4 Lyme Borreliosis, Rickettsioses & Other Zoonotic and Travel-Related Skin Infections
Lyme Borreliosis
Lyme borreliosis is the most common tick-borne infection in Europe. It is caused by spirochaetes of the Borrelia burgdorferi sensu lato complex and transmitted by Ixodes ricinus ticks. The risk of transmission rises with the time the tick is attached.
| Species | Typical Clinical Picture in Europe |
|---|---|
| B. afzelii | Skin: erythema migrans, acrodermatitis chronica atrophicans, borrelial lymphocytoma |
| B. garinii | Neuroborreliosis |
| B. burgdorferi sensu stricto | Arthritis (the main species in North America) |
Clinical Stages
| Stage | Manifestations |
|---|---|
| Early localised (days to weeks) | Erythema migrans (EM): an expanding red patch at least 5 cm across, appearing about 3–30 days after the bite, often with central clearing. Borrelial lymphocytoma: a painless blue-red nodule on the earlobe (children) or nipple and areola (adults) |
| Early disseminated (weeks to months) | Multiple EM; neuroborreliosis (painful radiculitis, facial palsy, lymphocytic meningitis; Bannwarth syndrome); Lyme carditis (atrioventricular block) |
| Late (months to years) | Lyme arthritis (often the knee); acrodermatitis chronica atrophicans (ACA) |
Diagnosis
- Erythema migrans is a clinical diagnosis. Serology is often negative in early EM and is not needed. Patients should not wait for tests before treatment.
- Borrelial lymphocytoma and ACA: serology helps. ACA almost always shows high IgG antibody levels, and biopsy supports the diagnosis.
- Neuroborreliosis: CSF pleocytosis with intrathecal antibody production.
- Serology cannot distinguish active from past infection. Testing ticks is not recommended.
Acrodermatitis Chronica Atrophicans
ACA typically affects older women. It begins with bluish-red swelling on the extensor surface of a limb (often the back of a hand, foot, or knee), which slowly becomes atrophic, thin, "cigarette-paper" skin with visible veins. Firm fibrous nodules can develop near joints, and there may be a peripheral neuropathy. It is usually caused by B. afzelii.
Treatment (European guidance)
| Manifestation | First-Line | Alternatives | Duration |
|---|---|---|---|
| Erythema migrans | Doxycycline 100 mg twice daily or 200 mg once daily | Amoxicillin 500–1,000 mg three times daily (children, pregnancy); azithromycin (5–7 days) or cefuroxime | About 10–14 days (10 days of doxycycline is usually enough) |
| Borrelial lymphocytoma | Doxycycline or amoxicillin | As for EM | About 14 days |
| Acrodermatitis chronica atrophicans | Doxycycline or amoxicillin | Ceftriaxone if neurological involvement | About 21–28 days |
| Neuroborreliosis | Doxycycline 200 mg daily or IV ceftriaxone | — | About 14 days |
- Doxycycline is avoided in pregnancy and, in many countries, in young children, although short courses are increasingly accepted in children.
- Tick removal: remove promptly with fine tweezers or a tick card close to the skin. Routine antibiotic prophylaxis after a tick bite is not generally recommended in Europe.
- Some patients have fatigue or pain after treatment. Prolonged antibiotic courses do not help.
European Rickettsioses and Other Tick-Borne Infections
| Infection | Organism and Vector | Features | Treatment |
|---|---|---|---|
| Mediterranean spotted fever | Rickettsia conorii; brown dog tick (Rhipicephalus sanguineus) | Fever, headache, a black eschar ("tache noire") at the bite, and a maculopapular rash including palms and soles | Doxycycline |
| TIBOLA / SENLAT | R. slovaca; Dermacentor ticks | Scalp eschar with painful neck lymphadenopathy after a tick bite in cold months | Doxycycline |
| Tick-borne encephalitis | Flavivirus; Ixodes | Two-phase illness with meningoencephalitis; no specific skin sign | Vaccination for prevention |
| Tularaemia | Francisella tularensis; ticks, hares, rodents, water | Ulceroglandular form: ulcer at inoculation with large regional lymph nodes | Ciprofloxacin or doxycycline; gentamicin in severe cases |
Bartonella Infections
- Cat-scratch disease (Bartonella henselae): a papule or pustule at a cat scratch, followed after 1–3 weeks by tender regional lymphadenopathy. It is usually self-limiting; azithromycin shortens lymphadenopathy.
- Bacillary angiomatosis (B. henselae or B. quintana): red vascular papules and nodules in severely immunosuppressed patients, especially with advanced HIV, which mimic Kaposi sarcoma. Warthin-Starry silver stain shows the bacteria. Treat with erythromycin or doxycycline.
Infections from Animals and Animal Products
| Infection | Source and Features | Treatment |
|---|---|---|
| Erysipeloid (Erysipelothrix rhusiopathiae) | Fish, meat, and poultry handlers; a painful, well-defined violaceous plaque on the hand or finger, spreading slowly | Penicillin |
| Cutaneous anthrax (Bacillus anthracis) | Contact with animal hides, wool, or contaminated heroin; a papule becoming a painless black eschar with marked surrounding oedema | Ciprofloxacin or doxycycline; notify public health; do not debride |
| Pasteurella multocida | Cat and dog bites; rapid cellulitis within 24 hours | Co-amoxiclav (also for prophylaxis of high-risk bites) |
| Mycobacterium marinum | Fish tanks and swimming pools; granulomatous nodules, sometimes in a sporotrichoid line | See the mycobacterial section |
| Orf and milker's nodule | Sheep and goats; cattle | See the poxvirus section |
Travel-Related Infestations
| Condition | Cause | Features | Treatment |
|---|---|---|---|
| Cutaneous larva migrans | Animal hookworm larvae (for example Ancylostoma braziliense) from beaches and soil | Itchy serpiginous tracks on the feet or buttocks, moving a few mm to cm a day | Ivermectin single dose or albendazole for 3–7 days |
| Larva currens | Strongyloides stercoralis autoinfection | Fast-moving urticarial track around the buttocks and thighs; risk of hyperinfection with corticosteroids | Ivermectin; screen before immunosuppression in at-risk patients |
| Tungiasis | Sand flea Tunga penetrans | Painful papule with a central black dot, usually on the toes | Sterile extraction; tetanus cover |
| Furuncular myiasis | Fly larvae (for example Dermatobia hominis) | Boil-like lesion with a central pore and a sensation of movement | Occlude the pore, then extract the larva |
| Leishmaniasis | Leishmania species | See the parasitic infections section | — |
Test Your Knowledge
A 40-year-old woman from Austria has a 12 cm expanding red patch with central clearing on her thigh, 10 days after removing a tick. Borrelia serology is negative. What is the correct management?
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Test Your Knowledge
A 72-year-old woman has a slowly progressive, bluish-red, thin, wrinkled "cigarette-paper" area on the back of one hand and forearm, with visible veins and a firm nodule near the elbow. Borrelia IgG antibody levels are very high. What is the diagnosis, and how long should antibiotic treatment last?
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Test Your Knowledge
A man returns from a summer holiday in southern France with fever, headache, and a maculopapular rash including the palms and soles. There is a small black crusted ulcer on his ankle where he removed a tick. What is the most likely diagnosis and treatment?
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Test Your Knowledge
After a beach holiday in Thailand, a woman has intensely itchy, raised, wandering serpiginous tracks on the sole of her foot that move a few millimetres each day. What is the treatment of choice?
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