Diagnostic challenges in Ixodes tick-borne Lyme disease presenting with atypical erythema migrans: a clinical case

Abstract

The clinical and epidemiological diagnosis of the erythematous form of Ixodes tick-borne borreliosis (Lyme disease) typically poses no difficulties for an infectious disease specialist. Diagnostic challenges arise when there is no history of a tick bite and when the presentation of erythema migrans is atypical. This skin manifestation must be differentiated from various dermatological, allergic, and other inflammatory conditions. In such complex cases, laboratory confirmation is required. With appropriate antibiotic therapy, erythema migrans typically resolves rapidly.
The present case report illustrates these diagnostic difficulties due to the absence of a reported tick bite and the atypical presentation of the erythema, which included papules, vesicles, and hemorrhagic components.
For a correct and timely diagnosis of Lyme borreliosis, even in the absence of a known tick bite, a detailed exposure history is essential. This includes assessing the patient's residence in or travel to an endemic area and any outdoor activities (e. g., walking in forested or park areas) during the tick season. The classic clinical picture is characterized by a red patch or spot, typically exceeding 5 cm in diameter, that expands centrifugally. In rare cases (reported in 1–4.8 % of patients), the erythema migrans lesion may be accompanied by atypical features such as papules, vesicles, pustules, or hemorrhages.