Cat-scratch disease is a generally benign, self-limited condition caused primarily by Bartonella henselae that usually manifests with regional lymphadenopathy, although visceral organ, neurologic, or ocular involvement can occur. A history of contact with saliva or scratch from a cat (especially kittens with fleas) is usually present. Cat-scratch disease typically starts with an inoculation lesion, which sequentially will appear vesicular, erythematous, and then papular. Lymphadenopathy near the site of inoculation usually appears within 2 weeks of skin inoculation and may persist for months. In rare cases, patients may develop complications such as ocular disease (neuroretinitis and Parinaud oculoglandular syndrome), encephalitis, osteolytic lesions, hepatosplenic lesions, weight loss, prolonged fever, and fatigue. The differential diagnosis includes lymphogranuloma venereum, bacterial adenitis, sarcoidosis, infectious mononucleosis, tumors (benign or malignant), tuberculosis, tularemia, brucellosis, and histoplasmosis.
Management and Disposition
The disease is usually self-limited, and management is primarily symptomatic. Parents and patients should be reassured that the nodes are benign and frequently resolve within 2 to 4 months. Although self-resolving, treatment with antimicrobials has been shown to decrease the duration of symptoms and is recommended. The antibiotic of choice is azithromycin. Other options include clarithromycin, trimethoprim-sulfamethoxazole, rifampin, or ciprofloxacin. Patients with hepatosplenic, neurologic, or neuroretinal disease should be treated with parenteral antibiotics (rifampin plus gentamicin or azithromycin). If the diagnosis is in doubt, serologic assays for Bartonella species can be sent. Surgical excision of the affected nodes is generally unnecessary.
Cat-scratch disease is the most common cause of regional adenopathy and should be considered in all children or adolescents with persistent lymphadenopathy.
Parinaud oculoglandular syndrome is characterized by a unilateral conjunctivitis and preauricular lymphadenopathy caused by B henselae.
Even in the presence of severe and multiple hepatic lesions, liver transaminase levels are normal and hepatomegaly is rare.
B henselae is a rare cause of unilateral neuroretinitis and vision loss.
In cases treated with antibiotics, a Jarisch-Herxheimer reaction may occur, which manifests as fever, tachycardia, hyperventilation, hypotension, peripheral vasodilation, diffuse myalgias, and exacerbation of skin lesions.
Cat-scratch Disease. An erythematous, tender, suppurative node is seen in a young febrile patient with a history of cat scratch on the extremity. The node required drainage 2 days later. (Photo contributor: Kevin J. Knoop, MD, MS.)
Cat-scratch Disease. The precipitating wound that caused the suppurative node in Fig. 14.89. (Photo contributor: Kevin J. Knoop, MD, MS.)