Mediterranean Spotted Fever Workup
- Author: Jason F Okulicz, MD; Chief Editor: Michael Stuart Bronze, MD more...
Laboratory Studies
- Mediterranean spotted fever is diagnosed based on clinical symptoms and epidemiologic data followed by serologic evidence of recent exposure to rickettsiae.
- Serologic assays are sometimes difficult to interpret, since members of the spotted fever group have extensive cross-reactivity.
- In some cases, R conorii can be isolated from blood or skin biopsy at the eschar site.
- Polymerase chain reaction or Western blot studies can be used to differentiate R conorii from Rickettsia africae. Species isolation should be considered in patients with unusual cases, including severe disease, and those traveling from areas with poorly defined rickettsial activity.[5]
- Currently, indirect fluorescent antibody is the most commonly used test to confirm the diagnosis of Mediterranean spotted fever. Serum specimens should be collected early in the disease course.
- R conorii may be cultured from blood samples using Vero cells, primary chicken embryo, fibroblast, and other cell lines or by intraperitoneal inoculation of adult male guinea pigs.
Histologic Findings
Characteristic histopathologic findings at the site of the primary lesion consist of epidermal ulceration, hyperplasia of the endothelium of the small dermal antinodes, and perivascular infiltrates in the dermis.
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