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erythema chronicum migricans (erythema migrans)

Etiology: - associated with early, localized Lyme disease (Borrelia burgdorferi) - recurrent erythema migrans represents reinfection with a different genotype of Borrelia burgdorferi rather than relapse [3] - Southern tick-associated rash illness Epidemiology: - 80% of patients with Lyme disease Clinical manifestations: 1) lesion develops subsequent to & surrounding the site of a tick bite 2) incubation period 5-14 days 3) annular, sometimes urticarial, erythematous lesion with central clearing [2] 4) lesions are single (75%) or multiple (25%) 5) lesions > 5 cm in size 6) lesions expand over days, resolve over weeks 7) systemic symptoms common & may be only manifestation * images [5,6,7,8,9,10,11] Laboratory: - no laboratory testing recommended [2] - arguments for no testing in [2] less than convincing - Borrelia burgdorferi DNA from skin biopsy - Borrelia burgdorferi serology may be negative in early, localized Lyme disease Differential diagnosis: - tick bite reaction: a) incubation period hours b) size: < 1 cm c) expands over hours, resolves over days d) systemic symptoms rare - Streptococcal cellulitis a) progresses over hours b) very tender c) patients often very ill - burn (history) - fixed drug eruption (history) - dermatophyte infection a) less erythema b) evolves more slowly than erythema migrans c) raised active border with central clearing - necrotic spider bite (endemic areas) Management: - see Lyme disease - empiric oral therapy 14-21 days, regardless of cause [2] (however, it would seem prudent to determine the cause) - 1st line agents - doxycycline 100 mg PO BID - amoxicillin 500 mg PO TID - cefuroxime 500 mg PO BID - alternative agent: azithromycin 500 mg PO QD - intravenous ceftriaxone for cardiac or neurologic manifestations or evidence of disseminated Lyme disease

Related

Lyme disease

General

sign/symptom skin lesion

References

  1. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 176
  2. Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018.
  3. Physician's First Watch, Nov 15, 2012 David G. Fairchild, MD, MPH, Editor-in-Chief Massachusetts Medical Society http://www.jwatch.org - Nadelman RB et al. Differentiation of reinfection from relapse in recurrent Lyme disease. N Engl J Med 2012 Nov 15; 367:1883 - Steere AC. Reinfection versus relapse in Lyme disease. N Engl J Med 2012 Nov 15; 367:1950
  4. Stonehouse A, Studdiford JS, Henry CA An update on the diagnosis and treatment of early Lyme disease: "focusing on the bull's eye, you may miss the mark". J Emerg Med. 2010 Nov;39(5):e147-51. Epub 2007 Oct 18. PMID: 17945460
  5. Wikipedia: Erythema chronicum migrans (image) https://en.wikipedia.org/wiki/Erythema_chronicum_migrans
  6. MedicineNet.com Picture of Lyme Disease (Erythema-Migrans) http://www.medicinenet.com/image-collection/lyme_disease_erythema-migrans_picture/picture.htm
  7. Centers for Disease Control and Prevention (CDC) Signs and Symptoms of Untreated Lyme Disease. http://www.cdc.gov/lyme/signs_symptoms/
  8. Blanton L, Keith B, Brzezinski W. Southern Tick-Associated Rash Illness: Erythema Migrans Is Not Always Lyme Disease Medscape http://www.medscape.com/viewarticle/583023 South Med J. 2008;101(7):759-760. PMID: 18580719
  9. DermNet NZ. Lyme disease http://www.dermnetnz.org/bacterial/lyme.html
  10. Burns DO 7 Bug Bites You Need to Know Medscape. June 17, 2021 https://reference.medscape.com/slideshow/bug-bites-6004328
  11. Steele RW Lyme disease Medscape. June 15, 2022 https://reference.medscape.com/slideshow/tick-borne-illnesses-6006369