Walker D H
J Dermatol. 1989 Jun;16(3):169-77. doi: 10.1111/j.1346-8138.1989.tb01244.x.
Spotted fever group rickettsioses comprise Rocky Mountain spotted fever (Rickettsia rickettsii), boutonneuse fever (R. conorii), North Asian tick typhus (R. sibirica), Queensland tick typhus (R. australis), rickettsialpox (R. akari), and Oriental spotted fever (R. japonica). Ticks or mites serve as the vector and reservoir hosts of the rickettsiae. These obligate intracellular bacteria invade vascular endothelial cells, which are damaged directly, causing increased vascular permeability. The rash usually appears in Rocky Mountain spotted fever on the third day of illness and later evolves to become petechial maculopapules in 50% of cases with involvement of the palms and soles in a similar proportion of patients. Eschar occurs in some SFG rickettsioses at the site of tick bite, but rarely in Rocky Mountain spotted fever. Diagnosis often proves difficult, and laboratory assays for antibodies to SFG rickettsiae are generally useful only in convalescence. Rickettsiae are demonstrable by diagnostic immunohistology in biopsies of rash or eschar. Empiric treatment with doxycycline, tetracycline, or chloramphenicol should be given early in the course on the basis of clinical suspicion of the diagnosis of a SFG rickettsiosis.
斑点热群立克次体病包括落基山斑点热（立氏立克次体）、纽扣热（康氏立克次体）、北亚蜱传斑疹伤寒（西伯利亚立克次体）、昆士兰蜱传斑疹伤寒（澳大利亚立克次体）、立克次体痘（小蛛立克次体）和东方斑点热（日本立克次体）。蜱或螨是立克次体的传播媒介和储存宿主。这些专性细胞内细菌侵入血管内皮细胞，直接造成细胞损伤，导致血管通透性增加。落基山斑点热的皮疹通常在发病第三天出现，随后在50%的病例中演变为瘀点性斑丘疹，同样比例的患者手掌和脚底也会出现皮疹。在某些斑点热群立克次体病中，蜱叮咬部位会出现焦痂，但落基山斑点热中很少见。诊断往往很困难，针对斑点热群立克次体抗体的实验室检测通常仅在恢复期有用。通过诊断性免疫组织学方法，可在皮疹或焦痂活检中发现立克次体。基于临床怀疑斑点热群立克次体病的诊断，应在病程早期给予强力霉素、四环素或氯霉素进行经验性治疗。
