Fever and Rash

Petechial, purpuric, and macular skin eruptions are associated with several important systemic infections.

Because many of these infections are due to meningitis-causing organisms or present with a headache as well as a rash, a lumbar puncture frequently is a necessary part of the routine evaluation of these illnesses.

Initial therapy of the severely ill patient with fever and a disseminated rash must include coverage for the more common and life-threatening diseases that can present in this way, including meningococcemia, pneumococcemia, and Rocky Mountain spotted fever.

Unless the initial history and physical examination strongly suggest a particular diagnosis, a reasonable empiric regimen is ceftriaxone, 2 g IV q12h, plus doxycycline, 100 mg IV or PO q12h. Antimicrobial coverage can be altered once the results of additional studies (e.g., cultures and susceptibility tests) are available.

Specific considerations

Neisseria meningitidis septicemia (meningococcemia) should be considered in any febrile patient with a petechial, purpuric, or macular rash because of its high mortality and potentially rapid course. The diagnosis can frequently be made from a Gram stain of petechial scrapings, a peripheral blood buffy-coat specimen, or cerebrospinal fluid (CSF) if concomitant meningitis is present. The treatment of choice for confirmed meningococcemia is penicillin G, 300,000 units/kg/day (maximum, 24 million units/day), divided into q2h doses. Antimicrobial susceptibility testing should be performed; PCN-resistant strains require cephalosporin administration. Chloramphenicol can be used in the severely beta-lactam-allergic patient.

Encapsulated bacteria such as Streptococcus pneumoniae and Haemophilus influenzae may produce a clinical presentation similar to that of meningococcemia, primarily in asplenic patients

Rocky Mountain spotted fever due to Rickettsia rickettsii typically begins with fever, chills, headache, and myalgias. A characteristic macular rash develops 1-5 days later. With time, the rash may become petechial. Treatment with doxycycline, 100 mg IV or PO q12h for 14 days, or chloramphenicol, 1 g IV q6h for 14 days, is recommended

Ehrlichiosis, due to Ehrlichia chaffeensis and other Ehrlichia species, may present with a rash and be clinically indistinguishable from Rocky Mountain spotted fever. Treatment consists of doxycycline, 100 mg IV or PO q12h. Chloramphenicol is not effective

Other infections associated with macular, maculopapular, or petechial rashes include typhoid fever (rose spots), endocarditis, disseminated gonorrhea, and disseminated candidiasis in the neutropenic host.

Noninfectious causes include drug reactions [e.g., trimethoprim-sulfamethoxazole (TMP/SMX)] and collagen vascular disease (e.g., systemic lupus erythematosus). Self-induced disease must be considered in patients with persistent, refractory skin lesions.