Uncovering Latent Tuberculosis Masquerading as Bartonella henselae Infection in a 12-Year-Old Patient.

Bartonella henselae, the causative agent of cat scratch disease (CSD), and Mycobacterium tuberculosis are two distinct pathogens that may affect the same patient, particularly in areas where both are common and risk factors overlap. We report the case of a 12-year-old Hispanic boy from South Texas, living near the USA-Mexico border, who presented with cervical swelling and mild periorbital edema for more than two weeks. Outpatient evaluation identified recent kitten exposure and positive Bartonella henselae IgM titers, leading to a diagnosis of CSD. Clindamycin was prescribed due to a documented penicillin allergy, although it is not considered first-line therapy. The patient's lymphadenopathy persisted after completing treatment, prompting admission to our hospital for further evaluation. During hospitalization, azithromycin, the CDC-recommended first-line antibiotic, was started for CSD, and latent tuberculosis infection was also identified. Our case illustrates how an acute illness can dominate the clinical presentation, overshadowing an underlying latent condition, creating a diagnostic blind spot, thus reinforcing the need for comprehensive history-taking, systematic evaluation, and a broad differential diagnosis, especially in patients with multiple risk factors.