Many common infectious diseases may initially manifest as fever without local symptoms, i.e., fever may be ahead of other signs and symptoms of the disease for hours or days.
For example, osteomyelitis in infants can manifest only fever, before they appear sore when pressed. In children with measles, fever for 24 hours may be ahead of cough and runny nose. With pneumonia, fever may occur 6 to 12 hours earlier than cough and often 24-48 hours earlier than wheezing in the lungs.
For a number of infectious diseases characterized by the development of fever a few days before the onset of other symptoms. So, childhood rubella can manifest itself only with fever for 4-5 days before the rash appears.
The prodromal period of a number of infectious diseases is characterized by fever of various durations, for example, with infectious mononucleosis (4–5 days), Q fever (5–6 days), lymph node syndrome with mucous-skin changes (up to 2 weeks), and chickenpox (1— 3 days). In some acute infectious diseases, fever may be the only symptom. According to McMillan, fever without local symptoms can manifest viral infections such as ECHO, Coxsackie, influenza, parainfluenza and adenovirus infection.
In differential diagnosis, the possibility of non-infectious acute diseases, such as appendicitis, pancreatitis, pulmonary embolism, acute rheumatic fever, serum sickness, etc. should be taken into account. , can proceed as acute febrile diseases.
In addition, heat diseases (thyroid crisis, atropine poisoning, heat stroke) can be incorrectly regarded as diseases accompanied by fever.