The development of lesions on the palms and soles is usually a late finding (1). Purpuric skin
lesions have been described in 60% to 100% of meningococcemia cases and are most commonly
seen at presentation (Fig. 1) (14,15). Histological studies demonstrate diffuse vascular damage,
fibrin thrombi, vascular necrosis, and perivascular hemorrhage in the involved skin and
organs. The skin lesions associated with meningococcal septic shock are thought to result from
an acquired or transient deficiency of protein C and/or protein S (16). Meningococci are
present in endothelial cells and neutrophils, and smears of skin lesions are positive for gram-
negative diplococci in many cases (17,18).
The diagnosis of meningococcemia is also aided by culturing the petechial lesions. Blood
cultures should be drawn. Admission laboratory data usually demonstrate a leukocytosis and
thrombocytopenia. Patients with meningococcemia but without meningitis will have a normal
cerebrospinal fluid (CSF) profile. If meningococcal meningitis is present, the CSF culture is
usually positive although the Gram stain may be negative. Typically, the CSF-associated
glucose is low and the protein elevated.
Chronic Meningococcemia
Chronic meningococcemia is rare, and its lesions differ from those seen in acute
meningococcemia. Diagnosis of chronic meningococcemia is challenging. Patients present
with intermittent fever, rash, arthritis, and arthralgias occurring over a period of several weeks
to months (19,20). The lesions of chronic meningococcemia are usually pale to pink macules
and/or papules typically located around a painful joint or pressure point. Nodules may
develop in the lower extremities. The lesions of chronic meningococcemia develop during
periods of fever and fade when the fevers dissipate. These lesions (in contrast to those of acute
meningococcemia) rarely demonstrate the bacteria on Gram stain or histology (5,8).
Polymerase chain reaction (PCR) testing of skin biopsy specimens may prove to be a valuable
method of diagnosis for this rare entity (21).
RSMF
RMSF, the most lethal rickettsial disease in the United States, is caused byRickettsia rickettsii
(22–25). Infection occurs approximately seven days after a bite by a tick vector (Dermacentor or
Rhicephalus). Two hundred fifty to twelve hundred cases of RMSF are reported annually (26).
Patients who have frequent exposure to dogs and live near wooded areas or areas with high
grass may be at increased risk of infection. RMSF is more common in men and is most
prevalent in the southern Atlantic and southern central states. North Carolina and Oklahoma
are the states with the highest incidence, accounting for over 35% of the cases. Over 90% of
patients are infected between April and September. During this season, there are increased
Figure 1 Purpuric skin lesions on an infant with meningococcal septicemia.Source: Courtesy of the CDC Public
Health Image Library.
24 Engel et al.