Chapter 64: Tick-Borne Infections

High-Yield Facts

• Children may be at higher risk for tick-borne infections than adults due to outdoor activities and potentially not noting attached ticks as readily as adults.

  • The most common tick-borne infection in the United States is Lyme disease, most common along the Atlantic seaboard and the upper Midwest.

  • The most common symptom of early localized Lyme disease is the erythema migrans (EM) (target) rash, which occurs within the first 2 weeks after the bite, at which time the antibody response is still negative (making localized Lyme a clinical diagnosis).

• Early disseminated Lyme disease occurs in approximately 15% of children several weeks after the tick bite. The most common symptom is multiple EM lesions; other manifestations can include facial nerve or other cranial nerve palsies and lymphocytic meningitis. Carditis is rare in children.

• Late Lyme disease can be seen as a complication of untreated early-stage Lyme. The most common symptom is relapsing large joint arthritis; neuropathy and meningoencephalitis are rare in children.

• The selection, route, and duration of antibiotic therapy depend upon the child's age, stage of Lyme disease, and site of infection. There is no convincing evidence for chronic Lyme disease, and courses of therapy longer than 4 weeks are not supported by the existing literature.

• Rocky Mountain spotted fever (RMSF) is a rickettsial disease most common in the southeastern and south central Midwest characterized by fever, headache, and rash. The rash begins as a maculopapular rash that then becomes petechial; it starts on the wrists/ankles and spreads centrally.

  • Multiorgan system failure and death can be seen with untreated RMSF, so for children suspected of having RMSF, treat empirically with doxycycline without waiting upon serologic confirmation.

• Ehrlichiosis is divided into two forms: human monocytic ehrlichiosis (HME) and human granulocytic anaplasmosis (HMA). The two entities cause very similar symptomatology, of fever, rash, myalgias, and headache, although HME can cause more severe symptoms than HMA. They both are treated with doxycycline.

  • Tularemia can be spread by contact with ticks or rabbits and other small mammals. A number of syndromes may be seen in patients, including ocular, lymphatic, and pharyngeal involvement. The treatment of choice is an aminoglycoside.

• Babesiosis causes a malaria-like illness in children; disease severity is highest in asplenic children. Diagnosis (peripheral smear) and treatment (clindamycin + quinine) are the same as for malaria.

Ticks can transmit a number of diseases to children; these include bacterial (Lyme, RMSF, ehrlichiosis, tularemia), protozoal (babesiosis), and viral (Colorado tick fever) pathogens. The index of suspicion for tick-borne pathogens should be high in children with unexplained fever or dermatologic findings: a child's play or other activities may put them at higher risk of contact with ticks than adults; the history of tick exposure infrequently is elicited; even if a child notes a tick, tick removal may not occur promptly or thoroughly; and children may become more ill with certain tick-borne diseases than adults.

Tick season will vary geographically (Table ...