[Acquired nystagmus in a 12-year-old boy as initial presentation of Lyme disease].

We report the case of a 12-year-old boy presenting with acquired horizontal nystagmus, headaches, and vertigo. CT, MRI, viral tests, and the Lyme disease test were at first negative. We made the diagnosis of neuroborreliosis based on a repeated Lyme disease test and lumbar puncture revealing intrathecal synthesis of specific antibodies. Adjusted antibiotic treatment led to complete disappearance of symptoms. Lyme borreliosis is difficult to diagnose and should be sought in case of unusual neuro-ophthalmic signs, especially in children.