Dermatological manifestations of tick-borne viral infections found in the United States

Abstract

Tick-borne diseases (TBDs) are bacterial, viral, and parasitic diseases transmitted by ticks. Viral TBDs have increased in prevalence over the last decade with many new pathogenic viruses being discovered. Doxycycline is often empirically prescribed by clinicians to treat symptomatic patients following tick bites due to suspicions of bacterial TBDs such as Rocky Mountain spotted fever, anaplasmosis, and ehrlichiosis. However, viral TBDs are included in the differential diagnosis if patients do not clinically improve following antibiotic therapy. Several viral TBDs present with dermatological manifestations. Recognizing the differences in clinical presentations of TBDs, particularly of newly emerging viral TBDs in the United States, can help physicians identify the viral TBD, and possibly rule out viral illnesses with different clinical presentations. Therefore, this review discusses clinical manifestations, with an emphasis on dermatologic manifestations of Heartland Virus, Bourbon Virus, Powassan Virus, Deer Tick Virus and Colorado Tick Fever Virus. KEY POINTS: Viral tick-borne diseases have increased in prevalence over the last decade and often have similar clinical manifestations to other tick-borne diseases, including bacterial infections. Here, we review the dermatologic manifestations of Heartland Virus (HRTV), Bourbon Virus (BRBV), Powassan Virus (POWV), Deer Tick Virus (DTV) and Colorado Tick Fever Virus (CTFV) that are important for clinicians.

Fig. 1

The key symptoms of each tick-borne illness are illustrated in the figure above. Infection with Heartland virus (HRTV) presents with fever, anorexia, and fatigue. Cases have shown an erythematous rash with central necrosis in HRTV-infected patients; however, the rash is not a reliable symptom for diagnosis. Laboratory findings will include thrombocytopenia, leukopenia, and elevated transaminases (aspartate transaminase and alanine transaminase). Bourbon virus-infected individuals develop fever, anorexia, nausea, vomiting, myalgia, and arthralgia. In addition, they may present with diffuse maculopapular or a papular rash that appears on the torso. Laboratory findings will show leukopenia, lymphopenia, thrombocytopenia, hyponatremia, and increased transaminases. Patients with Powassan virus (POWV) infections present with neuroinvasive or non-neuroinvasive diseases. Non-neuroinvasive POWV condition presents with a sore throat, drowsiness, headache, disorientation, faint maculopapular rash, and rarely fever. Neuroinvasive presentations of POWV infections include encephalitis, meningoencephalitis, ophthalmoplegia, and aseptic meningitis. Deer Tick virus, a genetic variant of POWV, presents with similar symptoms, including the distinctive erythema migrans rash, bilateral palmar rash, and possible progression to acute kidney injury. Colorado Tick Fever virus-infected patients present biphasic fever, headache, myalgia, maculopapular rash, and fatigue. Patients may also uniquely present with hyperesthesia or skin which is highly sensitive to stimulation. Laboratory tests show leukopenia and thrombocytopenia. Each of the five viral tick-borne illnesses presents unique clinical symptoms, and recognizing them is key to diagnosing and treating the patient