Common causes include:
Brucellosis
Chlamydia
Colorado tick fever virus
Coxiella burnetii
Dengue fever
Drug fever
Legionella
Leptospirosis
Leishmaniasis
Mycoplasma
Psittacosis
Tularemia
Typhoid fever
Yellow fever
Faget sign
WES sign
Broselow color zones
Beers criteria
De Winter's T waves
Sgarbossa's criteria
Bezoar
Ottawa ankle rules