Spirochetes

B. burgdorferi

Vector: tick Eastern USA, Great Lakes:Ixodes dammini (also known as I. scapularis)

Western US:
Ixodes pacificus

Europe:
Ixodes ricinus (reservoir: white-footed mouse)

Tick feeds on infected host (white footed mice, white tailed deer) → transmission to humans via infected tick saliva

Early localized disease: flu-like symptoms + erythema migrans: expanding erythematous patch at site of tick bite with central clearing, occurs ~1–2 weeks after tick bite, average diameter 5 cm, disappears typically within 4 weeks without treatment

Early disseminated disease: oval-shaped widespread patches (satellite erythema migrans lesions) due to spirochetemia, neural involvement (facial nerve common), migratory joint pain, carditis

Chronic disease: persistent neurologic and rheumatologic symptoms, acrodermatitis chronic atrophicans: loss of subcutaneous fat with thin, atrophic skin

Diagnosis: PCR, tissue culture, serologic evidence

Treatment: Adults, children (>8 years old): Doxycycline × 14–21 days, Pregnant women, children (<8 years old): Amoxicillin × 14–21 days

Borrelial lymphocytoma
(Lymphocytoma cutis)

B. afzelli
B. garinii (neither present in North America – only Europe)

Firm bluish-red tumor or plaque appears most commonly on ear lobes of children or nipple/areolae in adults, less commonly involves genitalia, trunk, or extremities

Doxycycline

Relapsing fever
(Louse-borne)

B. recurrentis

Vector: body louse
Pediculus humanus var. coporis

Paroxysmal fevers, myalgias, no specific cutaneous findings

Doxycycline

Relapsing fever
(Tick-borne)

B. parkeri, B. hermsii

Vector: soft ticks Ornithodoros

Same as louse-borne relapsing fever

Risk of Jarisch–Herxheimer reaction

Doxycycline

Leptospirosis
(For Bragg fever)
(Pretibial fever)
(Weil disease)

Leptospira interrogans

Direct skin contact with water contaminated by urine of infected animal

Fever, headache, painful pretibial plaques, conjunctivitis, jaundice, ± diffuse exanthem

Pencillin (macrolides and doxycycline also effective)

Yaws (Frambesia)

Treponema pallidum
(subspecies pertenue)

Transmission: direct contact with infections lesions

–Primary: one to few erythematous papules at inoculation site (“mother yaw”) usually on lower leg of child → enlarges, ulcerates and disappears with resultant scar

–Secondary: smaller “daughter yaws” lesions spread symmetrically over body

–Tertiary: skin and skeletal changes (no CNS or cardiovascular problems): gummata, keratoderma, midfacial destruction, bony inflammation and damage, nodular lesions

		Of note, mucosal yaws appear similar to condyloma lata

Pinta (Carate)

Treponema carateum

Transmission: direct contact with infections lesions (± possible insect vectors)

–Primary: smooth papule at inoculation site

–Secondary: small psoriasiform yellowish-brown papules and plaques (pintids)

–Tertiary: depigmented vitiligo-like lesions over face, wrists, trochanteric areas

Endemic syphilis (Bejel)

Treponema pallidum
(subspecies endemicum )


Transmission: direct skin contact

–Primary: skin lesions rare

–Secondary: mucosal lesions including mucous patches, condylomata lata, and lymphadenopathy, ± osteitis, periostitis, bony damage, gummata (CNS and cardiovascular problems very rare)