Infectious Disease

Atypical Presentation of Cat-Scratch Disease

Monica Liao Chang, MD, and Roberto P. Santos, MD

Bernard and Millie Duker Children’s Hospital, 
Albany, New York

M. Kristina Subik, MD

Albany Medical Center, Albany, New York

Monica Liao Chang, MD, and Roberto P. Santos, MD
Bernard and Millie Duker Children’s Hospital, Albany, New York

M. Kristina Subik, MD
Albany Medical Center, Albany, New York

Chang ML, Santos RP, Subik MK. Atypical presentation of cat-scratch disease. Consultant for Pediatricians. 2011;14(11):527-528.


A previously healthy 11-year-old boy presented with a 6-week history of fever and abdominal pain with alternating diarrhea and constipation. He had no sick contacts, recent travel history, or household pets. 

Earlier in the course of the illness, he had been evaluated by several medical providers at an urgent care center and an emergency department. He had had three chest radiographs, an abdominal ultrasonography scan, and two computed tomography scans of his abdomen, the latter of which showed an appendicolith and thickening of the terminal ileum (A). He was admitted on the sixth week of illness for fever of unknown origin.

On physical examination, he had a fever (37.8° to 38.3°C) without changes in sensorium, rash, lymphadenopathy, or hepatosplenomegaly. He had right lower quadrant tenderness on palpation. Inflammatory markers were elevated (C-reactive protein, 153 mg/dL; erythrocyte sedimentation rate, 120 mm/h). Blood, stool, and urine cultures were negative for pathogens. Upper gastrointestinal endoscopy and colonoscopy results were normal. Further history revealed that the family had 6 cats.

The boy was started empirically on doxycycline while awaiting serologic test results for Bartonella henselae, which eventually showed an immunoglobulin G titer of 1:256, four times above baseline. Biopsy results of the terminal ileum showed a necrotizing granuloma (B). His symptoms improved after 2 weeks of doxycycline.

Repeated history and physical examination is the cornerstone in the evaluation of fever of unknown origin (FUO). B henselae infection is the third leading infectious cause of FUO, after Epstein-Barr virus infection and osteomyelitis. A history of exposure to cats is not found uniformly among those with bartonellosis, which should be considered in the initial evaluation of FUO regardless of known exposure to cats.1

B henselae infections can affect many organs and can cause a broad range of clinical syndromes, including FUO, cat-scratch disease (CSD), and hepatosplenic disease. Typical CSD is characterized by fever and localized lymphadenopathy. Bacillary angiomatosis lesions may be seen in immunocompromised patients.1,2 Our patient had an atypical presentation; one other similar case has been reported in an adolescent boy with a sustained fever for 3 weeks, anorexia, weight loss, and right lower quadrant pain.3 Ultrasonography showed that the boy in that case had increased thickness of the terminal ileum that was confirmed to be associated with B henselae infection.

A high index of clinical suspicion is needed in diagnosing FUO associated with CSD. Laboratory tests that may be helpful include polymerase chain reaction (PCR), serology tests for B henselae antibodies, and biopsy with histopathology. PCR may be useful, but B henselae is detected in the blood during the first 6 weeks from onset, whereas most patients often are investigated several weeks after the onset of disease. Antibody titers greater than 1:64 are suggestive of B henselae infection.2 The histologic hallmarks include granulomatous lesions with central stellate microabscess.4

Treatment of mild infections is supportive, while severe infections are treated with antibiotics. Doxycycline is the preferred antibiotic for atypical and more serious infections due to its excellent intracellular penetration.1 Other agents known to be effective include azithromycin, ciprofloxacin, gentamicin, rifampin, and trimethoprim-sulfamethoxazole. The optimal duration of treatment may be several weeks for systemic disease.5


1. Florin TA, Zaoutis TE, Zaoutis LB. Beyond cat scratch disease: widening spectrum of Bartonella henselae infection. Pediatrics. 2008;121(5):e1413-1425.

2. Massei F, Gori L, Macchia P, Maggiore G. The expanded spectrum of bartonellosis in children. Infect Dis Clin North Am. 2005;19(3):691-711.

3. Massei F, Massimetti M, Messina F, Macchia P, Maggiore G. Bartonella henselae and inflammatory bowel disease. Lancet. 2000;356(9237):1245-1246.

4. Lamps LW, Scott MA. Cat-scratch disease: historic, clinical, and pathologic perspectives. Am J Clin Pathol. 2004;121(suppl1):S71-S80.

5. Cat scratch disease (Bartonella henselae). In: Kimberlin DW, Brady MT, Jackson MA, Long SL, eds. Red Book: 2015 Report of the Committee on Infectious Diseases. 30th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2015:280-283.