Lesion

A Young Man with a New Skin Lesion of the Right Shoulder

Ronald Rubin, MD—Series Editor

Volume 55 - Issue 7 - July 2015

A 22-year-old man presents for evaluation of a skin rash of 2 weeks duration. The “rash” is actually a single lesion on his right shoulder, which began as a small red spot and slowly enlarged in an ovoid manner. It evolved to the point of having several small vesicles in its middle and a still enlarging ovoid edge. This is very little, if any, pain. 

Upon a review of systems, he does note mild fatigue and diminished ability to perform his job. The patient has recently graduated college and has been working as a full-time landscaper over the summer. His duties are essentially all outdoors; he works in short sleeves and he is right-handed.

Physical Examination

On exam, the only abnormality is the right shoulder on which there is a 20 cm ovoid red lesion that manifests a more slightly deeper red margin and a central area with a cluster of small vesicles. The lesion is nontender to palpation, without any areas of necrosis.

Laboratory Tests

The patient’s complete blood count as well as metabolic and hepatic panels are all normal.

Which of the following statements regarding the presented patient is correct?

A. Cure rates and prognosis for this patient are excellent, approaching 90%.
B. Initial serologic testing is required and should be performed prior to any further evaluation or treatment.
C. Most cases require a prolonged (4-8 weeks) course of therapy to effect cure.
D. Eventual necrosis is likely to occur at the bite site and may require debridement and skin grafting.

Correct Answer: A, Cure rates and prognosis for this patient are excellent, approaching 90%.

The patient in this case clearly has Lyme disease, an important illness but one that quite likely has much more publicity and folklore importance in the United States than might be deserved when the data surrounding it is critically analyzed. Note: The most recent data indicated only 30,000 documented cases a year.1 

Lyme disease is caused by Borrelia burgdorferi and transmitted by deer ticks (eg, ixodes scapularis). Therefore, there is a firm epidemiology that indicates spring and summer seasonal incidence, a geographic distribution in New England and mid-Atlantic regions in the United States, an age preference related to exposure risk (people <50 years of age). All of which contribute to the clinical factors that are key in making the diagnosis.2 Therapy is now so effective that the prognosis is really quite excellent such that long-term sequelae and the concept of “chronic Lyme disease” is problematic at best.

Diagnosis

The diagnosis can and should be made when a patient presents with the cardinal sign of a typical skin lesion in a person from endemic region and with exposure probability.2,3 The classic lesion of Lyme disease is erythema migrans, skin lesions that appears within 1 to 2 weeks of the tick bite. 

Erythema migrans begins as a macule that enlarges and evolves into some form of “bull’s-eye” appearance. The center may be a clearing, vesiculation, or even enhanced erythema. The erythema migrans lesion may enlarge and can last several weeks. Nonetheless, unlike other insect bites (eg, spiders), the lesion essentially always resolves without eschar or necrosis formation; thus, Answer D is not correct. 

Systemic flu-like symptoms of fatigue, headache, arthralgia, and fever often coincide with this skin lesion. When these findings occur in a patient living in an endemic area who has exposure risk (outdoors occupation or recreational hobby) in history, the diagnosis of Lyme disease can be made with confidence. Serologic testing, one of the aspects of great discussion in both the medical and lay literature, is generally of little use in the diagnosis of Lyme disease in patients who manifests the findings discussed above. In fact, most serologic findings have very poor sensitivity and specificity.2

Antibodies IgM and IgG can persist for years after an infection, such that their presence are as likely an indication of past infection as an acute, new one. Therefore, Answer B is incorrect.

Treatment

Therapy for Lyme disease is excellent. When the fortunate situation of knowing that the tick bite exposure in <72 hours, a single dose of doxycycline is 87% effective in preventing Lyme disease.4 In established Lyme disease, a variety of effective regimens have been developed, including doxycycline, amoxicillin, or cefuroxime administered orally for 2 to 3 weeks. All yield efficacy in the 90% range.2 Therefore, the correct statement here is Answer A.

In the unusual case where systemic symptoms do not resolve with these therapies, residual symptomatology usually abates over time. Copious, well-done studies involving prolonged administration either acutely or for persistent subjective symptomatology have demonstrated either no benefit or at most minimal benefit and carry substantial risk of adverse effects.5,6 Thus, Answer C is not correct.

Outcome of the Case 

Lyme disease was diagnosed clinically and since the precise interval between tick bite was unknown, therapy with doxycycline 100 mg twice daily for 14 days was initiated. There was prompt relief of essentially all symptoms and at 1 month, the patient was asymptomatic and clinically well.

Take-Home Message

Lyme disease is caused by the spirochete Borrelia burgdorferi transmitted to humans by ixodid ticks. The herald lesion, which is usually clinically diagnostic, is erythema migrans. Common symptoms include fatigue, headache, arthralgia, and Bell’s palsy. Chemoprophylaxis can be preventative if the tick bite is <72 hours old, but otherwise a variety of excellent antibiotic therapies are available and should be taken for 14 to 21 days. No data demonstrates additional efficacy when administered for more protracted courses. Prognosis for cure is excellent, with incidence for mild, residual symptoms (eg, fatigue) being ≤10%.

Ronald Rubin, MD, is a professor of medicine at Temple University School of Medicine and chief of clinical hematology in the department of medicine at Temple University Hospital, both in Philadelphia, PA.

References:

  1. CDC. How many people get Lyme disease? March 4, 2015. www.cdc.gov/lyme/stats/humancases.html. Accessed June 10, 2015.
  2. Shapiro ED. Lyme disease. N Eng J Med. 2014;370(17):1724-1731.
  3. Steere AC, Sikand VK. The presenting manifestations of Lyme disease and the outcomes of treatment. N Eng J Med. 2003;348(24):2472-2474.
  4. Nadelman RB, Nowakowski J, Fish D, et al. Prophylaxis with single dose doxycycline for the prevention of Lyme disease after an ixodes scapularis tick bite. N Eng J Med. 2001;345(14):79-84.
  5. Feder HM Jr, Johnsonn BJ, O’Connell S, et al. A critical appraisal of “chronic Lyme disease.” N Eng J Med. 2007;357:(14)1422-1430.
  6. Klempner MS, Ju LT, Evans J, et al. Two controlled trials of antibiotic treatment in patients with persistent symptoms and a history of Lyme disease. 
  7. N Eng J Med. 2001;345(2):85-92.