Background: Cat-scratch disease (CSD) is mostly contracted by children and young adults. To our knowledge, CSD in elderly patients has never been characterized, and it may be underrecognized in this age group.
Methods: The study population included all patients with CSD diagnosed at our reference laboratory during 1991-2002. Demographic, clinical, and laboratory data for patients with CSD aged >or=60 years (elderly group) were compared with data for patients with CSD aged <60 years (nonelderly group).
Results: There were 846 immunocompetent patients with CSD included in this study. Fifty-two patients (6%) were >or=60 years old. Lymphadenopathy was less common in elderly patients than in nonelderly patients (76.5% vs. 94.4%; P<.001), and general malaise was more frequent in elderly patients (70.8% vs. 51.4%; P=.009). Atypical CSD was more common in elderly patients than in nonelderly patients (32.7% vs. 13.6%), including endocarditis (odds ratio [OR], 61.6; P<.001), encephalitis (OR, 6.3; P=.013), and fever of unknown origin (OR, 7.3; P<.001). The time period from onset of symptoms to diagnosis was >6 weeks for 29.5% of elderly patients versus 13.3% of nonelderly patients (P=.003).
Conclusions: CSD affects elderly persons as well as nonelderly persons, but clinical features differ between the patient groups. Atypical CSD, including endocarditis, is more frequent in elderly than in nonelderly patients. Conversely, lymphadenitis, the hallmark of typical CSD, is often absent in elderly patients. Lack of awareness among clinicians may delay the diagnosis of CSD in elderly persons and result in unnecessary and often invasive diagnostic procedures.