Suddenly felt very cold, then developed a fever.

Generally, fever refers to an elevated body temperature. Suddenly feeling very cold followed by a fever may be caused by exposure to cold, the common cold or influenza, leukemia, and other conditions, which require symptomatic treatment under medical guidance.

1. Exposure to Cold

When the body is exposed to cold, blood vessels constrict, slowing blood circulation and causing body temperature to drop. In response, the body raises its temperature through fever as a defense against potential viral or bacterial invasion. Under a doctor's guidance, medications such as acetaminophen tablets or ibuprofen sustained-release capsules can be taken for treatment.

2. Common Cold or Influenza

The common cold or influenza often causes symptoms including fever, headache, sore throat, and cough. Under medical supervision, treatments may include cold remedy granules or compound paracetamol and amantadine tablets.

3. Leukemia

Leukemia involves abnormal cells; when these atypical cells appear in the bloodstream, they can act as a source of heat, leading to fever. Under a doctor’s guidance, medications such as imatinib tablets or fludarabine phosphate tablets may be prescribed. Additionally, treatments such as chemotherapy or hematopoietic stem cell transplantation may be recommended under medical supervision.

Moreover, sepsis could also be a possible cause. Patients are advised to ensure adequate rest and nutrition, drink plenty of water to support recovery, maintain sufficient sleep, and avoid staying up late.