Emergency Medicine Book


Tick Bite

Aka: Tick Bite, Tick-Borne Disease, Tick Borne Illness, Alpha-gal Reaction
  1. See Also
    1. Black Legged Tick (Deer Tick)
    2. Vector Borne Disease
    3. Prevention of Tick-borne Infection
    4. Tick Removal
    5. Insect Bite
  2. Types
    1. Hard Ticks (Ixodidae)
      1. Hard body casing
      2. Head visible when viewed from above
      3. Responsible for most Tick-Borne Disease (due to ability to adhere to skin for days)
      4. Habitat: Tall grass and brush
    2. Soft Ticks (Argasidae)
      1. Soft, leathery body casing
      2. Head not visible when viewed from above
      3. Habitat: Animal nests
  3. History: Presentations suggestive of tick-borne illness
    1. Late spring through early fall presentation
    2. Flu-like symptoms
    3. Fever without obvious source
    4. Focal neurologic deficit
    5. Exotic travel or outdoor activities
    6. Pet or livestock exposure
    7. New severe, sudden, Allergic Reaction (Urticaria, Anaphylaxis) to red meat (Alpha-gal Reaction)
      1. Sensitization to galactose-alpha-1,3-galactose (alpha-gal)
      2. Alpha-gal is present in both ticks and red meat (lamb, pork, beef)
      3. Commins (2011) J Allergy Clin Immunol 127(5): 1286-93 [PubMed]
  4. Findings
    1. Rash
      1. Lyme Disease (Erythema Migrans)
        1. Develops days 3-21 after Tick Bite
        2. Target or erythematous Plaque >5 cm centered at bite site and gradually increasing to >10-20 cm
      2. Rocky Mountain Spotted Fever
        1. Erythematous Macules (day 6) that transition to Petechiae
      3. Alpha-gal Reaction
        1. Urticarial (or Anaphylaxis) in response to red meat
    2. Arthritis or Arthralgias
      1. Lyme Disease
        1. Monoarthritis (esp. knee, hip) as early presentation; late presentation with Polyarthritis
    3. Neurologic changes
      1. Lyme Disease
        1. Cranial Nerve dysfunction (esp. Bells Palsy), Meningitis, Sudden Hearing Loss, polyradiculoneuritis
      2. Tick Paralysis
        1. Ascending paralysis starting with leg weakness, areflexia, then upper extremity and head weakness
    4. Cardiac changes
      1. Lyme Disease
        1. Pericarditis, Myocarditis or AV Nodal block
    5. Viral-like syndrome (fever, Headache, malaise, Nausea, Vomiting, cough)
      1. Anaplasmosis
      2. Ehrlichiosis
      3. Rocky Mountain Spotted Fever
    6. Malaria-like presentation
      1. Babesiosis
        1. Fever, chills, myalgias, Headache, Dark Urine, Anorexia (and possible Hepatosplenomegaly and Jaundice)
  5. Labs: General
    1. Complete Blood Count
      1. Thrombocytopenia
      2. Leukopenia
    2. Serum Electrolytes
      1. Hyponatremia
    3. Renal Function tests (BUN, Creatinine)
      1. Decreased GFR
    4. Liver Function Tests
      1. Increased serum transaminases
  6. Labs: Diagnostic
    1. Does not direct initial management
      1. Most tests are delayed and may be initially normal
    2. Lyme Titer
      1. ELISA with confirmatory western blot
    3. Specific serologic tests (initial and repeated at 2-4 weeks)
      1. Anaplasmosis
      2. Ehrlichiosis
      3. Rocky Mountain Spotted Fever
    4. Polymerase Chain Reaction (PCR)
      1. Babesiosis
    5. Skin biopsy
      1. Rocky Mountain Spotted Fever (immunohistochemical staining)
    6. Peripheral Smear
      1. Anaplasmosis
        1. Neutrophils with intracytoplasmic inclusions (morulae)
      2. Babesiosis
        1. Maltese cross formation of RBC inclusions (appears similar to Malaria)
    7. No tests available
      1. Tick Paralysis
  7. Diagnostics
    1. Electrocardiogram
      1. AV Nodal Block or Pericarditis (secondary or tertiary Lyme Disease)
    2. Arthrocentesis of Monoarthritis
      1. Increased Synovial Fluid WBCs (may be indistinguishable from Septic Joint)
  8. Precautions
    1. Lack of known bite or lack of secondary bite reaction do not exclude Tick Borne Illness
    2. Prompt Tick Removal prevents pathogen transmission (e.g. Lyme Disease) and resolves Tick Paralysis
    3. Start empiric antibiotics immediately if Tick Borne Illness is suspected
      1. Untreated Rocky Mountain Spotted Feveray be lethal by day 8 after Tick Bite
      2. Untreated Lyme Disease may progress to AV Block, Pericarditis, Myocarditis, Polyarthritis, Meningitis, Bells Palsy
      3. Untreated Babesiosis may progress to DIC, Renal Failure and death
    4. Admit patients with significant complications of tick-borne illness
      1. Lyme Disease with Cardiac involvement (e.g. AV nodal block, Pericarditis, Myocarditis)
      2. Lyme Disease with CNS involvement (e.g. Meningitis)
      3. Rocky Mountain Spotted Fever (unless diagnosed early, before day 5 and before rash appears)
      4. Immunocompromised patients or significant complication of other tick-borne illness (Anaplasmosis, Ehrlichiosis)
      5. Babesiosis beyond early phase
  9. Management: Antibiotic Selection
    1. Doxycycline
      1. Avoided in age <8 years unless no alternative (due to dental effects)
      2. Lyme Disease
        1. Indicated in adults, children >8 years old, Penicillin allergic children at any age
      3. Rocky Mountain Spotted Fever
        1. Adults and children regardless of age (despite dental adverse effects)
        2. Do not delay treatment
      4. Anaplasmosis
        1. Adults and children regardless of age (despite dental adverse effects)
      5. Ehrlichiosis
        1. Adults and children regardless of age (despite dental adverse effects)
    2. Atovaquone with Azithromycin
      1. Babesiosis
    3. Clindamycin with Quinine
      1. Babesiosis
        1. Alternative regimen
    4. Amoxicillin
      1. Lyme Disease
        1. Indicated in children <8 years old and those allergic to docycycline
    5. Cefuroxime
      1. Lyme Disease
        1. Indicated in children <8 years old with Penicillin Allergy or those allergic to docycycline
    6. Ceftriaxone
      1. Lyme Disease
        1. Seconday or tertiary Lyme Disease
  10. Associated Conditions
    1. See Tick-Borne Disease
    2. American Dog Tick (Dermacentor variabilis)
      1. Q Fever
      2. Rocky Mountain Spotted Fever
      3. Tick Paralysis
      4. Tularemia
    3. Black-Legged Tick or Deer Tick (Ixodes Scapularis)
      1. Babesiosis
      2. Human Granulocytic Anaplasmosis (Human Granulocytic Ehrlichiosis)
      3. Lyme Disease
    4. Western Black Legged Tick (Ixodes pacificus)
      1. Same conditions as for Black-Legged Tick or Deer Tick above
    5. Brown Dog Tick (Rhipicephalus snguineus)
      1. Q Fever
      2. Rocky Mountain Spotted Fever
    6. Lone Star Tick (Amblyomma americanum, white spot on back)
      1. Alpha-gal Sensitivity (IgE Antibody to galactose-alpha 1,3-galactose)
        1. Anaphylaxis to red meat (beef, pork, lamb) as well as cetuximab (Erbitux)
      2. Human Monocytic Ehrlichiosis
      3. Q Fever
      4. Southern Tick-Associated Rash Illness (Masters Disease)
      5. Tularemia
    7. Pacific Coast Tick (Dermacentor occidentalis)
      1. Rickettsia phillipi (364D Rickettsiosis)
      2. Rocky Mountain Spotted Fever
      3. Tularemia
    8. Rocky Mountain Wood Tick (Dermacentor andersoni)
      1. Colorado Tick Fever
      2. Q Fever (unproven association)
      3. Powassan Encephalitis (unproven association)
      4. Rocky Mountain Spotted Fever
      5. Tick Paralysis
      6. Tularemia
    9. Soft Ticks (Ornithodoros)
      1. Local pain, inflammation and in some cases necrosis
      2. Relapsing Fever (Borrelia species)
    10. Woodchuck Tick (Ixodes cookei)
      1. Powassan Encephalitis
  11. Prevention
    1. See Prevention of Tick-borne Infection
    2. See Tick Removal
  12. Resources
    1. CDC Tickborne Diseases
      1. http://www.cdc.gov/ticks/diseases/
  13. References
    1. Green and Millsap (2016) Crit Dec Emerg Med 30(1): 4
    2. Juckett (2013) Am Fam Physician 88(12): 841-7 [PubMed]

Tick-Borne Diseases (C0162700)

Definition (MSH) Bacterial, viral, or parasitic diseases transmitted to humans and animals by the bite of infected ticks. The families Ixodidae and Argasidae contain many bloodsucking species that are important pests of man and domestic birds and mammals and probably exceed all other arthropods in the number and variety of disease agents they transmit. Many of the tick-borne diseases are zoonotic.
Concepts Disease or Syndrome (T047)
MSH D017282
SnomedCT 414018003, 415721003
English Tick-Borne Diseases, Disease, Tick-Borne, Diseases, Tick-Borne, Tick Borne Diseases, Tick-Borne Disease, TICK BORNE DIS, Disease transmitted by tick (navigational concept), Disease transmitted by tick (disorder), Tick-Borne Diseases [Disease/Finding], tick-borne diseases, tick borne diseases, borne disease tick, tick borne disease, diseases tick-borne, tick-borne disease, Tick-borne disease (disorder), Tick-borne diseases, Disease transmitted by tick, Tick-borne disease, Tick-borne infectious disease
Swedish Fästingburna sjukdomar
Czech nemoci přenášené klíšťaty
Finnish Puutiaisten levittämät taudit
Japanese ダニ媒介疾患
Spanish enfermedad transmitida por garrapatas (concepto para navegación), enfermedad transmitida por garrapatas (trastorno), infección transmitida por garrapatas, infección transmitida por garrapatas (trastorno), Enfermedades Transmitidas por Garrapatas, enfermedad transmitida por garrapatas, Enfermedades por Picaduras de Garrapatas
Polish Choroby przenoszone przez kleszcze
Norwegian Sykdommer overført ved flått
French Maladies transmises par les tiques, Maladies vectorielles à tiques, Maladies à tiques
German Zeckenübertragene Krankheiten
Italian Malattie trasmesse da zecche
Dutch Teekziekte, Teekziekten, Ziekte, teek-, Ziekten, teek-
Portuguese Doenças Transmitidas por Carrapatos
Derived from the NIH UMLS (Unified Medical Language System)

Tick bite (disorder) (C0241407)

Definition (MEDLINEPLUS)

If you spend time outdoors or have pets that go outdoors, you need to beware of ticks. Ticks are small bloodsucking parasites. Many species transmit diseases to animals and people. Some of the diseases you can get from a tick bite are Lyme disease, ehrlichiosis, Rocky Mountain spotted fever and tularemia.

Some ticks are so small that they can be difficult to see. Ticks may get on you if you walk through areas where they live, such as tall grass, leaf litter or shrubs.

Tick-borne diseases occur worldwide, including in your own backyard. To help protect yourself and your family, you should

  • Use a chemical repellent with DEET, permethrin or picaridin
  • Wear light-colored protective clothing
  • Tuck pant legs into socks
  • Avoid tick-infested areas
  • Check yourself, your children and your pets daily for ticks and carefully remove any ticks you find
Definition (MSH) The effects, both local and systemic, caused by the bites of TICKS.
Concepts Injury or Poisoning (T037)
MSH D064927
SnomedCT 95898004, 409983009
Dutch tekenbeet
French Piqûre de tique, Piqûres de tiques, Morsures de tiques
German Zeckenbiss, Zeckenbisse, Zeckenstiche
Italian Morso di zecca, Morsi di zecca
Portuguese Mordedura de carraça, Not Translated[Tick Bites]
Spanish Picadura de garrapata, Not Translated[Tick Bites], mordedura de garrapata (trastorno), mordedura de garrapata, mordedura de garrapata (anomalía morfológica)
Japanese ダニ咬傷, ダニコウショウ
English Tick bite (disorder), tick bite, Bites, Tick, Tick Bite, Tick Bites, Bite, Tick, Tick Bites [Disease/Finding], Tick bite, Tick bite, NOS, Tick bite (morphologic abnormality)
Czech Kousnutí klíštětem, kousnutí klíštětem, kousnutí klíštěte, kousnutí od klíštěte
Hungarian Kullancscsípés
Norwegian Flåttbitt, Flåttstikk
Derived from the NIH UMLS (Unified Medical Language System)

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