When It Comes to Ticks, It’s Okay to Make RASH Decisions

THE PATIENT

An otherwise healthy 16 year-old-male presents to the Emergency Department  (ED) with a rash on his chest that began one month prior to presentation. The patient reports that his dad noticed the rash today, prompting him to present to the ED. The patient denies any systemic symptoms including fevers, nausea, malaise, or abdominal pain. He states the rash is painless and does not itch. He has no memory of a tick bite but does spend time outdoors.

Vitals: 121/74, 90, 18, 99%, 37.2

The Rash

Figure 1

Diagnosis: Erythema Migrans (Lyme Disease)

DISCUSSION

Erythema migrans is an expanding skin lesion that is commonly seen in the earliest stages of Lyme disease. It is estimated to occur in 70-80% of infected persons. The rash begins at the site of the tick bite but may not show up until 3-30 days later. It is classically described as a “target” or bulls-eye shaped, circular, red rash with central clearing but can take different forms. In fact, only 20-30% of erythema migrans appear as the classic, target shaped, lesion. The rash may also present as a large red plaque with or without central clearing, or as a red-blue rash resembling a bruise. The rash is generally not painful or pruritic. All patients who live in Lyme-endemic areas who are identified to have the erythema migrans rash should be presumed to have Lyme disease and may be treated empirically.

Serological tests for Lyme are not necessary or useful at this stage of the infection because they are not usually positive until later in the disease course.

If left untreated, the rash may expand and will eventually disappear, and patients may go on to develop disseminated Lyme. If suspicion is high, treat early.

TREATMENT

In 2018, the American Academy of Pediatrics updated its guidelines to allow for ALL children, regardless of age, to receive doxycycline for Lyme disease as the risk of dental staining was shown to be low in courses less than 21 days. That being said, amoxicillin and cefuroxime axetil are as effective as doxycycline in treating erythema migrans.

CASE OUTCOME

The patient was discharged with a 14-day course of doxycycline and had complete resolution of his rash without development of further symptoms.

Lyme Quick Review

We tend to think of Lyme disease in three stages:

Early Localized: Erythema migrans rash with or without flu-like symptoms

Disseminated (develops in 1-4 months if untreated)

• multiple erythema migrans

• Rheumatologic manifestations:

  • migratory arthritis, effusions

• Cardiac manifestations:

  • AV block

  • Myocarditis/pericarditis

• Neurologic manifestations:

  • Bell’s palsy

  • Radiculopathy/neuropathy

  • Meningitis/Encephalitis 

Late Disseminated (if untreated):

• chronic inflammatory arthritis

• encephalopathy/encephalomyelitis

 Treatment for Disseminated and Severe disease: doxycycline or ceftriaxone

Prophylaxis for tick-bites:

Antibiotics after a tick bite are not recommended unless ALL of the following criteria are met:

• The patient lives in a Lyme endemic area

• The tick is identified as Ixodes scapularis

• The tick is attached for > 36 hours or is engorged

• Prophylaxis must be started within 72 hours of tick removal

Treatment consists of a single dose of 200mg doxycycline. Prophylaxis is NOT meant to prevent anaplasmosis, babesiosis, ehrlichiosis or Rocky Mountain Spotted Fever.

A word about Co-Infection:

There are many different tick-borne diseases and one tick can carry (and transmit) multiple diseases at once. Providers should have a high suspicion for co-infection, especially if patients are sicker than expected or if they are not improving after several days of treatment.

Faculty Reviewer: Dr. Kristina McAteer 

References:

1. Sanchez, Edgar, et al. "Diagnosis, treatment, and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis: a review." Jama 315.16 (2016): 1767-1777.

2.  Shapiro, Eugene D., and Gary P. Wormser. "Lyme disease in 2018: what is new (and what is not)." Jama 320.7 (2018): 635-636.

3. Taege, Alan J. "Tick trouble: overview of tick-borne diseases." Cleveland Clinic journal of medicine 67.4 (2000): 241-245.

4. Tickborne Diseases of the United States: A Reference Manual for Health Care Providers. U.S. Department of Health and Human Services Centers for Disease Control and Prevention, 2017, https://www.cdc.gov/lyme/resources/TickborneDiseases.pdf. Accessed 31 July 2019.

5. Bellis, J., and E. Tay. "Tick-borne illnesses: identification and management in the emergency department." Pediatric emergency medicine practice 15.9 (2018): 1-24.