Erythema nodosum is a delayed-type hipersensitivity reaction that presents as erythematous and painful nodules on the shins. It can appear as an uncommon complication of cat scratch disease produced by Bartonella henselae.
A rare case of erythema nodosum associated to cat scratch disease was diagnosed in our hospital. Its diagnostic, therapeutic management and evolution is reported.
We have found in previous literature just a single case of association between erythema nodosum and cat scratch disease in a pediatric patient.

Introduction: Bartonellosis is a common cause of fever of unknown origin with different clinical presentations.
Case report: We report a case of a 4 years-old girl who comes to the Emergency Department due to 11 days of fever of unknown origin. On admission, she complained of periumbilical pain. Abdominal ultrasound examination revealed hypoechoic hepatic space occupying lesion compatible with granuloma. Computed tomography confirmed the diagnosis. She refers causal contact with kittens at home. New laboratory findings included Bartonella IgM with posterior seroconversion. She was treated with rifampin and azithromycin for 1 month with early clinical repsonse. Lesions of granuloma disappeared completely later.
Conclusions: Visceral form of Bartonella was explained by contacts with cats, clinical and sonographic findings. Most cases occur in immunodeficient patients. However, this entity can be manifested in immunocompetent healthy children with controversial therapies