Causes

Fever is a common symptom of many medical conditions:

• Infectious disease, e.g. influenza, common cold, HIV, malaria, infectious mononucleosis, orgastroenteritis
• Various skin inflammations, e.g. boils, pimples, acne, or abscess
• Immunological diseases, e.g. lupus erythematosus, sarcoidosis, inflammatory bowel diseases
• Tissue destruction, which can occur in hemolysis, surgery, infarction, crush syndrome,rhabdomyolysis, cerebral hemorrhage, etc.
• Drug fever
  • directly caused by the drug, e.g. lamictal, progesterone, or chemotherapeutics causingtumor necrosis
  • as an adverse reaction to drugs, e.g. antibiotics or sulfa drugs.
  • after drug discontinuation, e.g. heroin or fentanyl withdrawal
• Reaction to incompatible blood products
• Cancers, most commonly renal cancer and leukemia and lymphomas
• Metabolic disorders, e.g. gout or porphyria
• Thrombo-embolic processes, e.g. pulmonary embolism or deep venous thrombosis

Persistent fever which cannot be explained after repeated routine clinical inquiries, is called fever of unknown origin.