Body lice can be eliminated by bathing and laundering clothing in hot water.

Because of W.L.’s severe infestation, he should also apply a topical pediculicide.

Products for head lice may be used for body lice with treatment repeated in 7 to 10

days.

85,94 Oral medications such as ivermectin is not FDA approved but has shown to

be more effective in some difficult-to-treat cases.

95 First-line treatment of pubic lice

is permethrin 1% or pyrethrins plus piperonyl butoxide. Alternative regimes include

malathion 0.5% lotion to be rinsed off after 8 to 12 hours or ivermectin 250 mcg/kg

to be repeated in 14 days.

96 The pruritus in W.L. can be symptomatically treated with

an antihistamine and a low-potency topical steroid.

Several “natural products” such as melaleuca plus lavender oil, coconut oil plus

anise oil, tea tree oil, petrolatum shampoo, mayonnaise, and Cetaphil have been used

in the management of lice.

97,98 None are FDA approved and have not been proven to

be more efficacious. Manual removal of nits by a fine-tooth comb can be a tedious

task but necessary because none of the pediculicides are 100% ovicidal. Application

of vinegar-based products 3 minutes prior to combing has been reported to make the

process of “nit-picking” easier.

86

Table 81-4

Application of Nonprescription and Prescription Options for Head Lice

Nonprescription products

a,b

Product Application directions

Permethrin 1% (Nix) Apply to damp hair that has been first shampooed with non-conditioning

shampoo and towel dried. Leave on for 10 minutes and rinse off

Repeat in 7–10 days if live lice are seen (re-treatment at 9 days is optimal)

Alternative treatment schedule: 0, 7, and 13–15 days

Conditioners and silicon-based products reduce residual effects of permethrin

Pyrethrins plus piperonyl

butoxide (Rid)

(available as mousse and

shampoo)

Apply to dry hair and leave on for 10 minutes prior to rinsing off

Retreatment schedules same as permethrin

Significant resistance has been developed reducing its effectiveness

Prescription products

Malathion 0.5% (Ovid) Lotion Apply to dry hair, let air dry then wash off after 8–12 hours

Repeat in 7–9 days if live lice are seen

Highly flammable because of alcohol content. Instruct patients to let hair air

dry uncovered––do not use hair driers, curling irons, or flat irons while hair is

wet

Resistance seen in the United Kingdom. Current US formulation differs from

European formulation––less resistance seen in the United States

Benzyl Alcohol 5% (Ulesfia) Apply a sufficient quantity to dry hair to saturate the scalp and the entire

length of hair. Leave on for 10 minutes then rinse off

Reapplication process is same as for permethrin

Spinosad 0.9% Suspension

(Natroba)

Apply to dry hair to saturate the scalp and work out to end of hair (may

require the entire contents of bottle). Leave on for 10 minutes and rinse off

Retreat in 7 days if live lice are seen

Ivermectin 0.5% Lotion (Sklice) Apply to dry hair and scalp, leave on for 10 minutes, and rinse off. Only one

application is needed

aAll topical products should be rinsed off over a sink with warm water––not in a shower or bath to limit exposure

to the skin.

bNits can be removed from the hair by using a sturdy fine-tooth comb.

There are various treatment options for head lice. Lack of adherence or failure to follow instructions may lead to

resistance or failure to eradicate the louse.

Sources: Adapted from: Devore CD, Schutze GE. The Council on school health and committee on infectious

diseases. Head lice. Pediatrics. 2015;135(5):e1355–e1365; Centers for Disease Control and Prevention (CDC)

Head Lice Treatment. http://www.cdc.gov/parasites/lice/head/treatment.html. Accessed July 31, 2015.

p. 1711

p. 1712

Petrolatum

To remove lice from W.L.’s eyelids or eyelashes, ophthalmic grade petrolatum

ointment can be used.

89 Petrolatum is applied to the eyelashes and lid margins with

cotton swabs –2 to 4 times daily. This regimen will either suffocate the lice or

physically remove them. Use of regular petrolatum may cause irritation to W.L.’s

eyes.

Decontamination Measures

Treatment for pediculosis should include thorough decontamination to avoid

reinfection. All personal articles of clothing, including bedding, should be washed

and dried in temperatures >130°F or 54.4°C.

86

Items that cannot be washed can be

dry-cleaned or placed in a plastic bag for 2 weeks. Furniture and carpeting should be

vacuumed; pediculicide spray is not recommended. Hairbrushes, combs, and other

plastic articles can be decontaminated by soaking in hot water.

99

In institutions and

schools where lice infestations are a problem, outer clothing (coats, hats, scarves) of

individuals should be isolated in separate plastic bags at the beginning of the day.

This measure will reduce reinfection significantly.

SCABIES

Prevalence

Scabies is a contagious skin infestation caused by the female mite, Sarcoptes scabiei

var. hominis. Infestations occur throughout the world and across all socioeconomic

groups. The mite is transmitted by an infested individual through close skin contact.

96

Crusted scabies (Norwegian scabies), typically seen in immunocompromised

individuals, is a more severe form that is highly infectious. Scabies outbreaks are

often seen in institutional settings such as nursing homes and prisons.

100 Typical

presentation is the presence of a pimple-like rash with intense itching. Those

presenting with crusted scabies have thick crusts of skin containing a large number of

mites and eggs.

Life Cycle

Adult females deposit eggs and feces (scybala) as they burrow under the skin. Once

the eggs hatch, larvae are released which eventually mature to nymphs and adult

mites. The female mite can live up to 6 weeks producing 2 to 4 eggs daily. The

classic presentation of skin lesions are a result of the burrowing action of the mites

and hypersensitivity reactions to their excrement. Most common sites of lesions are

in the interdigital finger webs, wrists, elbows, buttock, and genitalia.

101–103

Treatment

CASE 81-12

QUESTION 1: G.P., a 26-year-old nurse working at a nursing home, presents to her PCP with a pruritic rash

with excoriations in the interdigital webs of her hands and wrists. Several patients and nurses in the same

nursing home have similar symptoms as well as her 5-year-old son. Burrows were present in her finger webs

with a definitive diagnosis made from a skin scraping test. Microscopic examination revealed eggs of S. scabiei

and scybala.

How should G.P. and her family be treated? What special instructions and precautions should accompany

therapy?

There are several treatment options available for scabies. The treatment of choice

in patients 2 months or older is permethrin 5% cream.

102 A thin layer must be applied

to the skin from the neck to toes for 8 to 14 hours and then washed off. Although not

FDA approved, oral ivermectin 200 mg/kg as a single dose and repeated in 2 weeks

is also considered first-line treatment. A repeat dose is needed because of its limited

ovicidal activity.

104

Ivermectin is not recommended for children under the age of 5

years of age, <15 kg, pregnant, or lactating women.

102 Lindane should be considered

only as a second-line therapy because of reported toxicities.

105 Lindane is useful if

first-line therapies are not tolerated or if treatment fails.

Symptoms after exposure to scabies may take several weeks to appear for firsttime infections. Sexual partners and any other person who have prolonged contact

with an infested individual should be treated.

96 All members of the family should be

treated at the same time to avoid reinfestation. Symptoms may persist for up to 2

weeks, if symptoms persist after 2 weeks evaluate for treatment failure.

G.P. must be educated on the non-pharmacologic measures to manage scabies. All

bedding and clothing must be washed in hot water (140°F) and hot dried or drycleaned. Items that cannot be washed, such as stuffed toys, may be placed in a sealed

plastic bag for 48 to 72 hours because mites cannot survive for more than 72 hours

away from human skin.

96,106 Fumigation of living areas is not recommended.

ACKNOWLEDGMENT

The authors gratefully acknowledge Lin H. Chen, MD, Division of Infectious

Diseases, Mount Auburn Hospital, for her expert review of this chapter.

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Centers for Disease Control and Prevention (CDC). Scabies. Prevention and Control.

www.cdc.gov/parasites/scabies/prevent.html. Accessed June 29, 2015.

p. 1713

LYME DISEASE

Lyme disease is a multisystem spirochetal disease caused by the

bacterium Borrelia burgdorferi and is transmitted to humans through the

bite of infected black-legged ticks. Geography, tick species, and duration

of attachment are used to guide clinical decision-making.

Case 82-1 (Question 1)

Although clinical features of Lyme disease are diverse and vary with the

stage and duration of infection, the presence of an erythema migrans

(EM) skin rash is universally the most common feature.

Case 82-2 (Questions 1, 2)

Most cases of localized (early) Lyme disease can be treated effectively

with a few weeks of antibiotics (range of 10–21 days); however, if left

untreated, infection can spread to the joints, the heart, and the nervous

system.

Case 82-2 (Question 3, 4),

Case 82-3 (Question 1),

Case 82-4 (Question 1)

RELAPSING FEVER

Relapsing fever is a bacterial infection caused by certain species of

Borrelia spirochetes. Of the two types of relapsing fever, tick-borne

relapsing fever (TBRF) occurs in the western US and louse-borne

relapsing fever (LBRF) is generally restricted to refugee settings in

developing parts of the world.

Case 82-6 (Question 1)

BORRELIA MIYAMOTOI

Borrelia miyamotoi is a recently identified tick-borne organism

transmitted by Ixodes ticks and is endemic in the same areas as Lyme

disease, anaplasmosis, and babesiosis.

Case 82-6 (Question 2)

SOUTHERN TICK-ASSOCIATED RASH ILLNESS

Southern tick-associated rash illness (STARI) is a tick-borne disease

transmitted by the lone star tick and whose etiology is unknown.

Patients bitten may occasionally develop a rash similar to the rash of

Lyme disease.

Case 82-7 (Question 1)

ANAPLASMOSIS

Case 82-8 (Question 1)

Anaplasmosis, a tick-borne disease caused by the bacterium,

Anaplasma phagocytophilum, was first recognized as a disease of

humans in the United States in the mid-1990s. If not treated

appropriately, illness can be severe and potentially fatal.

BABESIOSIS

Babesiosis is an illness caused by parasites that infect red blood cells and

are spread by certain ticks, with symptoms ranging from asymptomatic

disease to potential fatality, especially in immunocompromised patients.

Case 82-9 (Questions 1, 2)

COLORADO TICK FEVER, TICK-BORNE ENCEPHALITIS,

AND OTHER VIRALLY MEDIATED TICK-BORNE DISEASES

Colorado tick fever (CTF) is a virally mediated tick-borne disease that

can be more severe in children than in adults. Other virally medicated

tick-borne diseases include those caused by Powassan, Bourbon, and

Heartland viruses.

Case 82-10 (Question 1)

p. 1714

p. 1715

TICK PARALYSIS

Tick paralysis occurs worldwide, affecting humans and livestock. It can

be reversed by tick removal.

Case 82-11 (Question 1)

PREVENTION OF TICK-BORNE ILLNESSES

Prevention of tick-borne diseases is always preferable to acquisition.

Personal protective measures and other methodologies aid in prevention.

Case 82-5 (Question 1)

OVERVIEW

Currently, the majority of emerging infectious diseases are arthropod-borne and are

caused by ticks and mosquitoes.

1 Unfortunately, with few exceptions, these emerging

diseases cannot be prevented by vaccinations. Ticks belong to the class Arachnida,

which includes scorpions, spiders, and mites.

2 Tick-borne diseases are a growing

problem worldwide, transmitting pathogens that cause diseases in humans and

animals.

3 As a vector of human illness worldwide, disease can be spread by ticks,

either by transmission of microorganisms or by injection of tick toxin into a host.

Bacterial, rickettsial, protozoal, and viral disease pathogens can be transmitted from

ticks to humans (Table 82-1).

4,5

p. 1715

p. 1716

Table 82-1

Tick-Borne Diseases

Disease

Causative

Agent Tick Vector Host

Endemic

Areas Comments

Bacterial

Anaplasmosis

(Human

granulocytic

anaplasmosis

(HGA))

Anaplasma

phagocytophilum

Ixodes scapularis,

Ixodes pacificus

Deer, elk, wild

rodents

North America

(upper Midwest

and

northeastern

US)

Previously was

known as

human

granulocytic

ehrlichiosis

(HGE)

Reported in

areas that

correspond to

the known

geographic

distribution of

Lyme disease

treatment:same

as ehrlichiosis

and RMSF

Ehrlichiosis Ehrlichia

chaffeensis,

Ehrlichia ewingii,

Ehrlichia murislike (EML)

Amblyomma

americanum

Deer, dogs North America

(southeastern

and southcentral US,

from the

eastern

seaboard

extending

westward to

Texas)

Similar clinical

presentation as

anaplasmosis

but transmission

by two different

species of ticks

and typically

occur in

different US

regions

New species

EML was

identified in

2009 in patients

in the upper

Midwest

Treatment:

same as

anaplasmosis

and RSMF

Lyme Disease Borrelia

burgdorferi

Borrelia mayonii

Ixodes scapularis,

Ixodes pacificus

Wild Rodents North America:

Borrelia

burgdorferi;

Borrelia mayonii

(new species

identified in

Midwestern

US; genetically

distinct from

Borrelia

Worldwide

caused by three

main species of

bacteria:

Borrelia

burgdorferi

(North

America), and

in Europe and

Asia: B. afzelii,

burgdorferi, B.

afzelii, and B.

garinii)

Europe: more

common in

eastern and

central Europe

Asia: northern

Asia B. afzelii,

and B. garinii

and B. garinii

Borrelia

Miyamotoi

Disease (BMD)

Borrelia

miyamotoi

Ixodes

scapularis;

Ixodes pacificus

First BMD

cases identified

in North

America in

2013

Tick-borne

Relapsing Fever

(TBRF)

Borrelia species

Borrelia hermsii,

B. parkerii, or B.

Turicatae

O. hermsii ticks;

O. parkerii, and

O. turicata

Rodents North America

(western states

in the United

States); Central

America, South

America, the

Mediterranean,

Central Asia,

and much of

Africa

Most cases

occur in

summer months

in rodentinfested cabins

but can occur in

winter months

when fires

warming a

cabin activate

ticks resting in

the

walls/woodwork

Tick-borne

Spotted Fever

Rickettsial

Infections,

broadly grouped

as “Spotted

Fever group

Rickettsia”

(SFGR)

a

Rickettsia species

Rickettsia parkeri

Worldwide:

Rickettsia

species including

R. conorii and R.

africae

various ticks

depending on

Rickettesia

species

North America:

United States:

R. parkeri

(Eastern and

southern US);

and Rickettsia

species 364D

(Northern

California,

Pacific coast)

Worldwide: all

continents

except

Antarctica;

numerous

Rickettsia

species

including R.

conorii and R.

africae

Rocky

Mountain

Spotted Fever

(RMSF)

Rickettsia

rickettsia

Dermacentor

variabilis,

Dermacentor

andersoni,

Rhipicephalus

sanguineus

Wild rodents,

ticks

North America:

United States

>60% of cases

occur in North

Carolina,

Oklahoma,

United States:

Reported

throughout most

of the

contiguous

states

Arkansas,

Tennessee, and

Missouri;

reports

increasing in

certain parts of

Arizona

Treatment:

same as

anaplasmosis

and ehrlichiosis.

Tularemia Francisella

tularensis

Dermacentor

variabilis,

Dermacentor

andersoni,

Amblyomma

americanum

Rabbits, hares,

and rodents;

domestic cats

Most common

in the southcentral US, the

Pacific

Northwest, and

parts of

Massachusetts

United States:

reported from

allstates except

Hawaii

Other

transmission

routes:

inhalation and

direct

inoculation

Parasitic

Babesiosis Babesia species

(most cases

Babesia microti)

Ixodes scapularis Mice, voles North America

(northeastern

and upper

Midwestern US

where Babesia

microti is

endemic); also

sporadic cases

on West Coast

Transmission of

Babesia

parasites can

occur by

transfusion

Viral

Colorado tick

fever

Coltivirus species Dermacentor

andersoni

Wild rodents,

mammals

North America:

western US and

southwestern

Canada (at

elevations of

4,000 to 10,000

feet)

Transmission

can occur from

person to

person (rare)

Heartland virus Phleboviruses Amblyomma

americanum

United States:

Missouri and

Tennessee

Worldwide

p. 1716

p. 1717

Tick-borne

Encephalitis

Member of virus

family Flaviviridae

Ixodes ricinus,

Ixodes

persulcatus

Rodents Europe:

temperate

regions,

forested areas

Asia: northern

Asia (temperate

regions,

forested areas)

May also be

acquired by

ingestion of

unpasteurized

dairy products

from infected

cows, goats,

and sheep

Powassan virus Member of virus Ixodes scapularis, North America:

family Flaviviridae Ixodes cookei United States

(northeastern

states and Great

Lakes region),

Canada

Europe: Russia

Crimean–Congo

Hemorrhagic

Fever (CCHF)

Virus

Nairo virus.

Family

Bunyaviridae

Ixodid ticks Asia, Africa,

and Europe

May also be

inquired by

contact with

infected blood,

saliva, or

inhalation

Omsk

Hemorrhagic

Fever Virus

(OHFV)

Member of virus

family Flaviviridae

Dermacentor

reticulatus,

Dermacentor

marginatus,

Ixodes

persulcatus

Europe:

southwestern

Russia

Kyasanur

Forest Disease

Virus (KFDV)

Member of virus

family Flaviviridae

Hemaphysalis

spinigera (hard

ticks)

Asia:southern

India, Saudi

Arabia (aka

Alkhurma

disease in Saudi

Arabia)

Associated with

exposure while

harvesting

agents

Other

Southern

Tick-Associated

Rash Illness

(STARI)

Amblyomma

americanum

Eastern,

southeastern,

and southcentral US

aRefer to CDC for further information on Other Tick-borne SFGR transmitted internationally:

http://www.cdc.gov/otherspottedfever/. Accessed January 17, 2017.

Source: Centers for Disease Control and Prevention. Tickborne diseases of the US:

http://www.cdc.gov/ticks/diseases/. Accessed July 23, 2017.

Tick Genus

Only two of the three families of ticks are of medical significance to humans: the

soft-bodied ticks, Argasidae, and the hard-bodied ticks, Ixodidae.

2 Four of the 13

genera of Ixodidae transmit disease in the United States: Dermacentor, Ixodes,

Amblyomma, and Rhipicephalus. Among the five genera of Argasidae, only

Ornithodoros are known to transmit pathogens to humans in the United States. Most

hard ticks have a 2- to 3-year life cycle, comprising the larval, nymphal, and adult

stages.

2 They require one blood meal during each stage before they can mature into

the next stage, and they usually remain attached to a host for hours or days. In

contrast, soft ticks may have multiple nymphal stages, and both nymphal and adult

forms can feast on blood multiple times, usually for only 30 minutes. However,

Argasidae can survive many years without blood sustenance and are long-lived.

2

Humans are the inadvertent hosts for the life cycle of almost all ticks and tick-borne

diseases.

LYME DISEASE

Lyme disease, or more accurately Lyme borreliosis, is a multisystem spirochetal

disease caused by several genospecies of the spirochete Borrelia burgdorferi sensu

lato.

5,6 Lyme disease, which is transmitted by a tick bite, was first recognized in the

United States in the mid-1970s, after a mysterious outbreak of arthritis near Lyme,

Connecticut.

6 However, illness consistent with late manifestations of Lyme disease

was described in Europe more than a century ago. In Europe and North America,

Lyme disease is now recognized as the most commonly reported vector-borne

disease.

6

Etiologic Agent

Three genomic subgroups of B. burgdorferi worldwide account for most human

infections: B afzelii, B garinii, and B burgdorferi sensu stricto (hereafter referred to

a s B burgdorferi).

6,7 Although all three groups have been found in Europe, most

isolates are Borrelia garinii or Borrelia afzelii, the North American strains identified

to date belong to the B. burgdorferi as the cause of Lyme disease.

Tick Vectors

There are four species of Ixodes ticks that commonly bite humans. In Europe and

Asia, I ricinus and I persulcatus are principal vectors, respectively. In the United

States, the black-legged or deer tick, I scapularis, is the principal vector in areas of

the Northeastern, Mid-Atlantic, and North Central states, whereas I. pacificus, the

western black-legged tick, is the principal human-biting vector in the western US.

6,7

The tick acquires the B. burgdorferi spirochete from feeding on an infected

reservoir host, such as mice, shrews, and other small mammals and various species

of birds. The spirochete remains dormant in the tick’s midgut until the tick feeds

again. The spirochete then passes through the salivary ducts of the tick and is injected

through the skin of the new host with the tick bite.

6,8,9

p. 1717

p. 1718

Few spirochetes are transmitted from the tick to its host during the first 24 to 36

hours of attachment. An infected nymphal tick, however, invariably transfers

spirochetes when attached to its host for more than 72 hours.

Most humans are infected through the bites of nymph ticks, which feed during the

spring and summer months. Larval and nymph ticks are small, less than 3 mm, size of

a freckle or poppy seed. Therefore, the tick often goes unnoticed, and fewer than half

of patients with Lyme disease recall having been bitten by a tick. The tick feeds on

small, medium, or large mammals, lizards, or birds during its larval and nymphal

(immature) stages.

2 Larval ticks are not relevant vectors for Lyme disease, however,

because they are rarely infected and become so only after feeding on an infected

host.

3 Adult ticks parasitize only medium or large mammals.

2 Although adult ticks can

also transmit Lyme disease bacteria, because they are much larger, individuals are

more likely to discover and remove them prior to transmission of bacteria.

Humans are inadvertent hosts of any stage of the tick. Although the tick can feed on

many different animals, each tick species has preferred hosts. The complex interplay

of spirochete, host, and vector in a particular area influences the risk of Lyme disease

after a tick bite. Lyme disease is not transmitted directly between people, and there

has not been substantive evidence of human transmission through sexual contact,

semen, urine, or breast milk.

6

Clinical Features and Diagnosis

LOCALIZED (EARLY) STAGE

Although clinical features of Lyme disease are diverse and vary with the stage and

duration of infection, the presence of an EM skin rash is universally the most common

feature, occurring in 60% to 90% of cases in North America.

6 The development of an

EM rash at the site of the tick bite is typically the first indication of transmission and

early infection in most North American patients.

8 The EM rash, which reflects the

innate immune response, occurs between 3 and 30 days (an average of 7 days).

Fever, headache, fatigue, muscle and joint aches, and swollen lymph nodes, and the

characteristic EM skin rash are the typical early signs and symptoms (3 to 30 days

after the tick bite).

4

Lyme disease is diagnosed based on patient symptoms, physical findings (e.g., EM

rash), and the possibility of tick exposure.

4,8–10 Because it is a multisystem condition,

if left untreated, infection can spread to the joints, the heart, and the nervous system.

Although laboratory methods can be helpful if used correctly, serologic tests are

insensitive during the first few weeks of infection. Though not necessary, in some

cases, acute and convalescent titers may be helpful in some cases. During this stage,

patient with an EM rash, systemic symptoms, and the possibility of tick exposure may

be diagnosed clinically. Appropriate antibiotics should be initiated in early stages of

Lyme disease.

DISSEMINATED STAGE

During the disseminated stage, serologic tests are usually positive and a standardized

two-tier testing protocol is recommended.

4,8,11 The Lyme disease presentation and

testing can be complex, and the reader is referred to the Centers for Disease Control

and Prevention (CDC) and other resources for further information.

4 During this stage,

a variety of manifestations may occur (Table 82-2).

Treatment

The clinical manifestations of Lyme disease should govern the treatment strategy.

4,11

Patients who receive appropriate treatment in the early stages of Lyme disease

usually recover rapidly and completely. Oral treatment regimens commonly used in

early-stage disease include doxycycline, amoxicillin, or cefuroxime axetil (Table 82-

3).

5 Patients with disseminated (late) Lyme disease should be evaluated for severity

and may require intravenous treatment.

4,11

CASE 82-1

QUESTION 1: C.J., a 32-year-old male, visits his primary care physician (PCP) with symptoms of low-grade

fever and muscle aches 2 days after camping in the western part of Massachusetts during the month of August.

He explained that he was canoeing and hiking with his family in the woods, and on the last day of their trip, he

noticed a small tick on his thigh and immediately destroyed it. A small, itchy spot that he felt at the site of the

tick bite is no longer symptomatic. C.J. asks his PCP whether he needs any laboratory tests and/or preventive

treatment. Given his presentation and tick bite history, what would be appropriate steps to management?

Table 82-2

Lyme Disease Clinical Manifestations

Early Localized Stage

Erythema migrans (EM) skin rash: red ring-like or homogenous expanding rash

Flu-like symptoms—malaise, headache, fever, myalgia, arthralgia

Lymphadenopathy

Disseminated Stage

Flu-like symptoms

Lymphadenopathy

Multiple secondary annular rashes

Cardiac Manifestations

Myocarditis or pericarditis

Conduction defects, varying degrees of atrioventricular or bundle-branch block, but permanent pacing not

indicated

Neurologic Manifestations

Bell’s palsy or other cranial neuropathy

Meningitis

Radiculoneuritis, myelitis

Sensory or motor peripheral neuropathy

Rheumatologic Manifestations

Transient, migratory arthritis and effusion in one or multiple joints

Migratory pain in tendons, bursae, muscle, and bones

Baker cyst

Arthritis may recur in same or different joints (if untreated)

Additional Manifestations

Conjunctivitis, keratitis, uveitis

Mild hepatitis

Splenomegaly

Source: Centers for Disease Control and Prevention. Tickborne Diseases of the United States. A Reference

Manual for Health Care Providers. 3rd ed. 2015.

The routine use of antibiotic prophylaxis or serologic testing is not recommended

for Lyme disease prevention following a recognized tick bite.

4,11 With regard to

C.J.’s situation, the use of serologic testing is not recommended because the antibody

response to B. burgdorferi is not detectable for the first few weeks after a tick bite.

Therefore, the blood tests for antibodies to B. burgdorferi are unlikely to be positive,

because C.J.’s tick bite occurred only 2 days ago.

8,10,11

p. 1718

p. 1719

Table 82-3

Treatment Recommendations for Localized (Early) Lyme Disease

Adults: doxycycline 100 mg, 2 times/day orally × 14 days (14–21 days)

Or

Amoxicillin 500 mg, 3 times/day orally × 14 (14–21 days)

Or

Cefuroxime axetil 500 mg, 2 times/day orally × 14 (14–21 days)

Children: amoxicillin 50 mg/kg/day orally, divided into three doses (maximum, 500 mg/dose) × 14 days (14–21

days)

Children: cefuroxime 30 mg/kg/day, orally, divided into two doses (maximum, 500 mg/dose) × 14 days (14–21

days)

Children (>8 years): may use doxycycline 4 mg/kg/day orally, divided into two doses (maximum, 100 mg/dose) ×

14 days (14–21 days)

Sources: Centers for Disease Control and Prevention. Tickborne Diseases of the United States. A Reference

Manual for Health Care Providers. 3rd ed. 2015; Wormser GP et al. The clinical assessment, treatment, and

prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: clinical practice guidelines by

the Infectious Diseases Society of America. [published correction appears in Clin Infect Dis. 2007;45(7):941]. Clin

Infect Dis. 2006;43:1089–1134.

The risk of developing Lyme disease can be affected by the rate of transmission of

the spirochete from infected ticks to humans, the length of time before the tick is

removed during its bite, the degree of blood engorgement of the tick (scutal index),

the prevalence of spirochete infestation of ticks in an area (which varies with the tick

species), and the reservoir competency of host animals in the region.

3

Although transmission rates of Lyme disease from an infected tick bite are

estimated at approximately 10%, the risk is reduced dramatically if the tick is

removed within 24 hours of attachment. The small, itchy spot experienced by C.J.

may represent a hypersensitivity reaction to the bite. These erythematous,

noninfectious skin lesions develop within 48 hours of tick detachment or may occur

while the tick is still attached. They are usually less than 5 cm in diameter; they may

have an urticarial appearance and usually disappear in 1 or 2 days.

4,6

Prophylactic antibiotic preventive therapy with a single dose of 200 mg of oral

doxycycline (children 8 years or older at 4 mg/kg to a maximum 200-mg dose) can be

offered if all of the following criteria are met: (a) There are no contraindications to

doxycycline use; (b) administration can start within 72 hours of tick removal; (c) the

tick can be reliably identified as a nymphal or adult I. scapularis tick with certainty

of the duration of attachment of 36 hours or more based on the degree of engorgement

or time of exposure; and (d) the local rate of infection of ticks by B. burgdorferi in

the area of exposure is 20% or greater based on current ecologic evidence.

3 Routine

testing of ticks themselves for tick-borne infections is not recommended.

11

Antibiotic prophylaxis after I. pacificus tick bites is generally not necessary

because of relatively low prevalence of B. burgdorferi infestation of I. pacificus

ticks.

11 However, C.J. had exposure in a region where B. burgdorferi is highly

prevalent among I. scapularis ticks. If there is uncertainty regarding the duration of

tick attachment, he may be offered a dose of doxycycline prophylaxis.

ERYTHEMA MIGRANS

Signs, Symptoms, and Disease Course

CASE 82-2

QUESTION 1: M.K., a 37-year-old woman, presents with right knee pain and multiple, large, discrete skin

rashes that she has had for the past 10 days. Three months ago, in July, she visited friends in Maine and spent

much of her time engaged in outdoor activities. Two months ago, her husband noticed a circular area of intense

redness, approximately 9 cm wide, in her left armpit. The rash grew considerably larger during the next 2

weeks and had a red outer border. M.K. attributed the expansion of the rash to having scratched the mildly

itchy area. The rash gradually disappeared. In late August, M.K. experienced fatigue, nausea, and headache for

a week and thought it was “summer flu.” In early September, she experienced right knee pain; ibuprofen

produced some relief.

On examination, she was afebrile and had mild soft tissue swelling of the right knee. Her white blood cell

(WBC) count was normal. Serum samples contained antibody titers to B. burgdorferi demonstrated by a

sensitive ELISA (enzyme immunoassay) followed by a Western blot for immunoglobulin M (IgM) and IgG. A

Venereal Disease Research Laboratory (VDRL) test for syphilis and a pregnancy test were negative.

M.K. is started on a 4-week course of oral doxycycline 100 mg twice daily. What characteristics of M.K.’s

skin rash are consistent with the EM of Lyme disease?

The EM of Lyme disease usually develops within 3 to 30 days (average 7 days) of

a usually asymptomatic tick bite at the site of inoculation of the spirochete. The rash

begins as an erythematous (red) macule or papule typically on the thigh, back,

shoulder, calf, groin, popliteal fossa, flank, axilla, buttock, or upper arm.

4,6,11

In

children, EM is often found on the head at the hairline, neck, arms, or legs. It expands

outwardly at 2 to 3 cm/day to a diameter of 5 to 70 cm (mean, 16 cm), occasionally

with some central clearing. Some cases of EM in the United States lack central

clearing. The rash may be warm to the touch and is usually painless, but some

patients have mild burning or itching. Up to 50% of patients with EM have multiple

secondary lesions that most likely represent blood-borne spread of the spirochete to

other skin sites rather than multiple tick bites.

5

If untreated, EM generally fades

within several weeks; if treated, it usually resolves in several days.

4,6,11

Low-grade fever and other nonspecific symptoms, such as malaise, headache,

myalgias, or arthralgias, may accompany EM.

4,6,11 Some individuals may have no

symptoms. Cough, rhinitis, sinusitis, and other respiratory symptoms do not usually

occur in Lyme disease.

4 Pitfalls in the diagnosis of EM exist. Lesions are sometimes

misdiagnosed. M.K.’s skin rash was large (>9 cm), red, and had a red outer border.

It gradually faded over the course of a few weeks. These characteristics are

consistent with a diagnosis of EM.

Serologic Testing

CASE 82-2, QUESTION 2: What might have been the rationale for the laboratory tests that were

undertaken in M.K.?

Guidelines currently recommend a two-tier approach of ELISA and confirmatory

Western blotting.

8,10,11 The sensitivity of such testing in Lyme arthritis cases is 97% to

100%.

9,11 However, routine use of serology testing for patients with early EM cannot

be recommended presently. Syphilis and other known biologic causes (periodontal

spirochetes) of false-positive serologic testing should

p. 1719

p. 1720

be excluded. Rheumatoid factor or antinuclear antibody tests usually are negative

in Lyme disease. These tests help differentiate rheumatoid arthritis or systemic lupus

erythematosus from Lyme disease. The WBC count is normal or mildly elevated in

Lyme disease. M.K. had a normal WBC. Pregnancy was ruled out before initiating a

tetracycline. Most interesting in M.K. is the presence of secondary EM lesions

representing disseminated infection.

The presence of EM as an early indicator of Lyme disease gives clinicians the best

opportunity for early diagnosis and treatment.

4,11

In the United States, the expression

of EM is the only manifestation of Lyme disease that is sufficiently distinctive to

allow clinical diagnosis in the absence of confirmatory laboratory information.

4,11

Early treatment can prevent sequelae of disseminated disease.

LYME DISEASE TREATMENT

Antibiotics

CASE 82-2, QUESTION 3: Why was doxycycline selected to treat M.K.?

Borrelia burgdorferi is susceptible to amoxicillin, tetracyclines, and some secondand third-generation cephalosporins. It is only moderately sensitive to penicillin G

and is resistant to first-generation cephalosporins, rifampin, cotrimoxazole,

aminoglycosides, chloramphenicol, and the fluoroquinolones.

4,11

Penicillin, tetracycline, and erythromycin historically were the drugs of choice for

the treatment of Lyme disease because they can be administered orally; they are

relatively inexpensive and appear to have good in vitro activity. However, this in

vitro activity does not translate to in vivo efficacy. Doxycycline is an agent of choice

for treatment of Lyme disease. Amoxicillin and cefuroxime axetil are also first-line

options. In Europe, in contrast, penicillin still is used with continued success. A

nondoxycycline regimen is preferred in pregnant or breast-feeding women and in

children younger than 8 years of age.

4,11

Compared with the third-generation cephalosporins, the oral second-generation

drug cefuroxime axetil has good in vitro activity and efficacy. But it is more

expensive than oral amoxicillin or doxycycline. Of the third-generation

cephalosporins, ceftriaxone has the most potent in vitro activity and a long half-life

for once-daily dosing in an outpatient program. Ceftriaxone is expensive, however,

and has a higher incidence of diarrhea than other β-lactams, probably owing to

extensive biliary excretion.

The macrolides clarithromycin and azithromycin are unpredictable in their in vitro

activity.