- Tick-borne infection caused by a spirochete of genus Borrelia.
- Small mammals are the primary reservoir for Borrelia.
- Ticks are vectors for transmission to humans.
- Most common initial manifestation is typical skin lesion known as
- Later manifestations may include arthritis, CNS or cardiac
- Mainstay of treatment is antibiotic therapy.
- Erythema migrans
- constitutional symptoms
- Facial palsy
- Arthritis or arthralgia
- Regional lymphadenopathy
- Stiff neck
- Lymphocytoma cutis
- Acrodermatitis chronica atrophicans
- AV block or myopericarditis
- Encephalomyelitis, peripheral neuropathy, encephalopathy
- 1st Tests To Order: ELISA or IFA
- Other Tests to Consider:
- Lyme-specific IgM and IgG
- skin biopsy culture
- Serologic testing — At the time of a tick bite, serologic
testing is not helpful in establishing a new diagnosis of B. burgdorferi
infection because antibodies to the spirochete have not yet appeared.
(See "Diagnosis of Lyme disease", section on 'Special considerations'.)
Following the onset of EM:
- IgM antibodies to B. burgdorferi typically appear within
one to two weeks.
- IgG antibodies to B. burgdorferi typically appear within
one to six weeks, depending upon the type of test that is used (eg,
C6 versus Western blot).
Thus, we do not obtain serologic testing with the aim of
diagnosing a new infection at the time of the bite.
However, obtaining a baseline serology in patients who have been
treated for Lyme disease in the past is helpful because it can serve
as a comparator to later serologies if signs and symptoms
- Testing ticks
- Although testing of individual ticks recovered from patients for
B. burgdorferi by polymerase chain reaction (PCR) is available
commercially, most experts do not recommend testing of ticks
since the results do not affect clinical management.
- If the tick has not been attached for at least 36 hours, it is
unlikely to have transmitted disease and no prophylaxis should be
offered, even if PCR is positive.
- If the tick has been attached for ≥36 hours, then
prophylaxis is recommended and a delay in initiation of prophylaxis
while awaiting results of testing could be detrimental.
- When an attached tick is detected, the first step involves tick
- Selected patients who seek care after detecting an attached tick may
receive antimicrobial prophylaxis if they meet specific criteria:
Antibiotic prophylaxis should be used only in patients who
meet ALL of the following criteria*
Attached tick identified as an adult or nymphal Ixodes
scapularis tick (deer tick)
Tick is estimated to have been attached for ≥36 hours (by
degree of engorgement or time of exposure)
Prophylaxis is begun within 72 hours of tick removal
Local rate of infection of ticks with B. burgdorferi is ≥20
percent (these rates of infection have been shown to occur in
parts of New England, parts of the mid-Atlantic States, and
parts of Minnesota and Wisconsin)
Doxycycline is not contraindicated (ie, the patient is not <8
years of age, pregnant, or lactating)
* If the patient meets ALL of these criteria, the recommended
dose of doxycycline is 200 mg for adults and 4 mg/kg
up to a maximum dose of 200 mg in children ≥8 years, given
as a single dose.
This regimen has never been tested in children; this
recommendation is extrapolated from experience in adults.
- Tick removal — Using proper technique for tick removal is
important. Several methods of tick removal have been advocated. A study
that evaluated the use of forceps or protected fingers, or the
application of petroleum jelly, fingernail polish, isopropyl alcohol, or
a hot match, found that only the use of forceps or protected fingers
resulted in the satisfactory removal of 29 adult American dog ticks
without leaving the mouthparts in the host skin.
- The proper technique for removal of the attached tick includes the
- ●If available, use tweezers or small forceps to grasp the tick
as close to the skin surface as possible. In the absence of
tweezers, use paper or cloth to protect the fingers during tick
●Pull straight up gently but firmly, using steady pressure. Do not
jerk or twist.
●Do not squeeze, crush, or puncture the body of the tick, since its
fluids may contain infectious agents.
●Disinfect the skin thoroughly after removing the tick and wash
hands with soap and water.
●If sections of the mouthparts of the tick remain in the skin, they
should be left alone as they will normally be expelled
●After the tick removal and the skin cleansing, the person bitten
(or the parents) should observe the area for the development of
EM for up to 30 days following exposure. Components of tick
saliva can cause transient erythema that should not be confused with
●Since the tick usually needs to be attached for two to three days
before transmission of the Lyme disease agent occurs, removal of the
tick within this time frame often prevents the infection
known tick bite
single-dose antibiotic prophylaxis
- Postexposure prophylaxis with a single dose of
doxycycline may be used for a significant exposure meeting
all of the following criteria:
1. An engorged
Ixodes scapularis tick is removed after at least an
estimated 36 hours of attachment.
2. Prophylaxis is started within 72 hours of tick removal.|
Borrelia burgdorferi prevalence in local ticks is
known to be greater than 20%.
4. Doxycycline is not contraindicated (contraindications
include children <8 years of age, pregnancy, or lactation).
Patients who cannot take doxycycline are started on
treatment if early symptoms develop.
- Doxycycline : children >8 years of age: 4
mg/kg/day orally as a single dose;
Adults: 200 mg orally as a single dose
Erythema migrans lesion with uniform erythema
Vesicular erythema migrans