If there are no cold symptoms and suddenly you have a fever, then it may not be caused by a cold cause. There are many conditions that cause fever because fever is just a symptom and its causes are many. The first, common fever caused by bronchial inflammation, pneumonia, etc., without a cold, is due to a fever caused by an inflammatory reaction. The second one, there may be urinary tract infections, which do not have the symptoms of cold, but also have fever. Thirdly, there are some patients with tumors who develop tumor fever and also have fever. There are also many other causes, such as inflammatory reactions and gout, that can be accompanied by fever, not necessarily fever after a cold.