What is the management approach for a patient presenting with fever and rash?

Management of Fever with Rash

Immediately assess for life-threatening conditions—meningococcemia, Rocky Mountain spotted fever (RMSF), and viral hemorrhagic fevers—and initiate empiric treatment without waiting for laboratory confirmation if clinical suspicion is high. 1, 2

Immediate Life-Threatening Exclusions

Petechial/Purpuric Rash Pattern

• Rule out meningococcemia and RMSF first in any patient presenting with petechial or purpuric lesions and fever 2, 3
• For suspected meningococcemia, administer broad-spectrum antibiotics immediately without delay 2
• For suspected RMSF, initiate doxycycline immediately regardless of patient age, even before laboratory confirmation 2
• RMSF typically begins as small pink macules on extremities that spread centrally and become petechial, with palms and soles involvement appearing late (day 5-6) 2
• Hospitalize patients with evidence of organ dysfunction, severe thrombocytopenia, or mental status changes 2

Hemorrhagic Fever Considerations

• Assess for viral hemorrhagic fever risk if travel to endemic areas occurred, and contact regional infectious disease centers for guidance on appropriate testing 1
• Look for nasal bleeding, petechial rash in axillary areas, positive tourniquet test, and hypotension as characteristic signs 4
• Implement appropriate isolation precautions immediately for suspected viral hemorrhagic fevers 1

Systematic Diagnostic Approach

Critical History Elements

• Document when the rash appeared in relation to fever onset, as this provides crucial diagnostic clues 2
• Identify the pattern of spread (centrifugal vs. centripetal) and specifically note involvement of palms and soles 2
• Obtain detailed travel history including specific countries visited, exact dates, activities, accommodations, and exposures to insects, animals, or ill individuals 1
• Assess for tick exposures or outdoor activities in wooded or grassy areas 2
• Review all medications for potential drug reactions 2
• Evaluate for immunocompromising conditions that may alter presentation 2
• Inquire about animal contacts, particularly rodents, as Streptobacillus moniliformis (rat-bite fever) presents with fever and maculopapular rash affecting palms 5

Essential Initial Laboratory Testing

• Perform malaria testing with three thick and thin blood films over 72 hours and/or rapid diagnostic test for any patient who visited a tropical country within the past year 1, 2
• Obtain complete blood count looking for thrombocytopenia (suggests dengue or RMSF), lymphopenia, or eosinophilia 1, 2
• Draw at least two sets of blood cultures before initiating antibiotics 1
• Assess liver function tests, renal function, and urinalysis for proteinuria, hematuria, or hemoglobinuria 1
• Check erythrocyte sedimentation rate and C-reactive protein levels 6

Travel-Related Fever and Rash

• Treat malaria empirically if there is high suspicion and the patient appears ill, even with initial negative tests 1
• For dengue suspicion, perform PCR or NS1 antigen test, and IgM serology if more than 5 days have passed since symptom onset 1
• Consider empiric doxycycline for rickettsial infections if exposure to ticks in game parks with fever, headache, and rash/eschar is suspected 1
• For enteric fever, consider empiric ceftriaxone while awaiting culture results if the patient is clinically unstable with appropriate travel history 1
• Most tropical infections become symptomatic within 21 days of exposure 2
• Consider chikungunya testing with PCR or IgM if travel to endemic areas is reported 1

Rash Morphology-Based Approach

Maculopapular Rash (Most Common Pattern)

• The most common causes are measles, cutaneous drug reactions, varicella, adult-onset Still's disease, and rickettsial disease 7
• Viral diseases among infectious causes and drug reactions among noninfectious causes are the leading etiologies 7
• Consider HIV testing if acute seroconversion illness is suspected, especially with maculopapular rash 1
• In infants and young children, consider exanthematous viral illnesses like roseola (HHV-6) 2

Supportive Care Considerations

• For dengue, provide supportive care with close monitoring of platelet count and hematocrit, and avoid aspirin due to bleeding risk 1
• Alert laboratory staff when suspecting infections that pose occupational hazards, such as brucellosis, viral hemorrhagic fevers, or Q fever 1
• Report notifiable diseases to local health protection units as required 1

Special Population Considerations

Immunocompromised Patients

• Maintain a lower threshold for hospitalization and empiric antimicrobial therapy 2
• These patients may present with atypical or more severe manifestations 2

Pediatric Considerations (MIS-C Context)

• Children with fever, rash, and systemic inflammation without other organ damage may be suitable for outpatient evaluation if well-appearing with reassuring vital signs and close follow-up can be ensured 6
• Perform tiered diagnostic approach with initial screening (complete blood count, metabolic panel, ESR, CRP, SARS-CoV-2 testing) followed by complete evaluation if concerning features present 6