DESCRIPTION

• Petechiae
  • Small hemorrhages (<3 mm in size) into the superficial layers of the skin
  • Manifest as a reddish purple, macular, nonblanching skin rash
• Purpura
  • Larger skin hemorrhages (>3 mm in size)
  • Often macular but may be raised or tender

EPIDEMIOLOGY

• Most patients (70–80%) presenting with fever and petechiae have defined or presumed viral infections, which are often caused by enteroviruses, adenovirus, or parvovirus B19.
• A minority of children presenting with fever and petechiae have an invasive bacterial disease, most commonly Neisseria meningitidis.
  • Infants and toddlers are at greatest risk of having an invasive bacterial infection with fever and petechiae.
  • Teenagers and young adults are most commonly affected by outbreaks of meningococcemia, presenting with fever and petechiae.
• Streptococcal pharyngitis may cause fever and petechiae in a well-appearing child.
• Other etiologies, such as acute leukemia, idiopathic thrombocytopenic purpura (ITP), and Henoch-Schönlein purpura (HSP), are responsible for a minority of cases of fever and petechiae.

GENERAL-PREVENTION

• Vaccine recommendations
  • All children should complete the Streptococcus pneumoniae and Haemophilus influenzae type B immunization series that begins at 2 months of age.
  • Routine childhood immunization with quadrivalent meningococcal conjugate vaccine (protects against serogroups A, C, Y, and W) is recommended for all children at 11 to 12 years of age and a booster dose at 16 to 18 years of age.
  • Infants and children at high risk for meningococcal disease, such as those with asplenia or terminal complement deficiencies, should receive meningococcal conjugate vaccine as early as 2 months of age.
  • Children ≥10 years at high risk for meningococcal disease should also receive a serogroup B vaccine, which is approved for ages 10 to 25 years and is administered in a 2 or 3 dose schedule depending on the formulation.
  • Annual immunization against influenza viruses is recommended for all children >6 months of age.
• Chemoprophylaxis is recommended for close contacts of patients with meningococcal disease. Ideally, treatment should begin within 24 hours; rifampin is the drug of choice in most children (dosing <1 month of age: 5 mg/kg PO every 12 hours × 2 days, ≥1 month of age: 10 mg/kg [maximum 600 mg] PO every 12 hours × 2 days). Alternatives include ciprofloxacin, ceftriaxone, and azithromycin.

PATHOPHYSIOLOGY

Petechiae may result from several different mechanisms:

• Disruption of vascular integrity—due to infections, vasculitis, or trauma
• Platelet deficiency or dysfunction—typically thrombocytopenia due to sepsis, disseminated intravascular coagulation (DIC), ITP, or leukemia
• Factor deficiencies, although these are more likely to manifest as ecchymoses or deep bleeding

ETIOLOGY

Petechiae, when accompanied by fever, most often have an infectious cause. Multiple organisms are associated with fever and petechiae. Less commonly, fever and petechiae may be caused by other entities such as acute leukemia, ITP, HSP, and bacterial endocarditis.

• Bacterial
  • N. meningitidis
  • S. pneumoniae
  • H. influenzae type B
  • Staphylococcus aureus
  • Streptococcus pyogenes
  • Escherichia coli
• Viral
  • Enterovirus
  • Adenovirus
  • Influenza
  • Parainfluenza
  • Parvovirus B19
  • Epstein-Barr virus (EBV)
  • Rubella
  • Respiratory syncytial virus
  • Hepatitis viruses
• Rickettsial diseases
  • Rickettsia rickettsii
  • Ehrlichiosis