Brazilian purpuric fever (BPF) is an illness of children caused by the bacterium Haemophilus influenzae biogroup aegyptius which is ultimately fatal due to sepsis.

At this time, young children between the ages of 3 months and 10 years were contracting a strange illness which was characterized by high fever and purpuric lesions on the body.

In documented BPF cases, the symptoms include high fever (101.3 °F/38,5 °C or higher), nausea, vomiting, severe abdominal pain, septic shock, and ultimately death.

The physical presentation of children infected with BPF include purpuric skin lesions affecting mainly the face and extremities, cyanosis, rapid necrosis of soft tissue, particularly the hands, feet, nose, and ears.

In a study conducted by Barbosa et al., a 60 kilodalton hemagglutinating extracellular product was suggested to be the major pathogenic factor linked to the hemorrhagic manifestations of BPF.

[citation needed] A positive BPF diagnosis includes the clinical symptoms (mainly the fever, purpuric lesions, and rapid progression of the disease), isolation of Haemophilus Influenzae Biogroup aegyptius from blood, and negative laboratory tests for Neisseria meningitidis.

If the conjunctivitis is found to be caused by H. aegyptius Biogroup III then prompt antibiotic treatment preferably with rifampin has been shown to prevent progression to BPF.

Although BPF is susceptible to many commonly used antibiotics, including ampicillin, cefuroxime, cefotaxime, rifampin, and chloramphenicol, by the time it is diagnosed the disease has progressed too much to be effectively treated.