A previously healthy boy aged 2 years presented to the emergency department with a painless erythematous nodule measuring 2 × 1.5 cm on the left earlobe, with onset one month prior and treated with a topical corticosteroid without improvement (Fig. 1, A and B). The patient was afebrile and had no other symptoms. He had been bitten by a tick in the left retroauricular region approximately four months before, during a trip to Switzerland, for which he did not receive antibiotic prophylaxis. A serologic test for Borrelia burgdorferi was positive for IgG antibodies, a result confirmed by Western blot at the Centro Nacional de Microbiología (National Microbiology Center). The patient received a diagnosis of lymphocytoma cutis and was treated with a 28-day course of oral amoxicillin at a dose of 50 mg/kg/day, with a favorable response (Fig. 2).
Lymphocytoma cutis is an infrequent manifestation of the early disseminated stage of European Lyme disease. This disease is caused by different Borrelia species, such as B burgdorferi or B afzelii, with the latter predominating and identified most frequently in cases in Central Europe.1,2 In Spain, the incidence of Lyme disease is low,3 although globalization and the increase in international travel contribute to the occurrence of imported cases. The investigation of the epidemiological context in the history-taking and the early identification of these uncommon manifestations are essential for preventing the systemic complications characteristic of disseminated Lyme disease.
