DESCRIPTIONA 2-year-old previously healthy boy presented with 24 h of fever, and painful right axillary and elbow swelling. He had a 2×2×2.5 cm non-tender, non-erythaematous, mobile axillary mass, oedema and mild erythaema of his lower right arm, and cervical and inguinal lymphadenopathy. Initial investigations showed: haemoglobin 106 g/L, white cell count 13.2×10 9 /L and C reactive protein 50 mg/L. Ultrasound confirmed lymphadenopathy and soft tissue oedema, and the patient was treated with oral co-amoxiclav for lymphadenitis. After 4 days, his treatment was changed to intravenous ceftriaxone due to persisting symptoms. His fever terminated on day five, and the axillary lymph node decreased slightly in size. The arm swelling remained, so oral clindamycin was added, with little further improvement. A number of investigations were planned to investigate the persisting swelling, including lymph node biopsy, but an MRI scan (figure 1) was diagnostic-it showed cellulitis, and epitrochlear and axillary lymphadenopathy, suggestive of cat scratch disease, due to the marked inflammation around the lymph node.1 Additional history revealed the family had two cats, including one kitten. The child was treated with azithromycin for 5 days. His Bartonella henslae IgG titre was 256, confirming the diagnosis. He made a full recovery.