What are the possible causes of a persistent low-grade fever for three consecutive days?

Low-grade fever is defined as a body temperature ranging from 37.3°C to 38.5°C. Mild low-grade fever generally does not cause significant harm to the body; however, identifying its underlying cause is crucial. So, what are the possible reasons for persistent low-grade fever lasting three consecutive days? Below, we address this question.

What Causes Persistent Low-Grade Fever for Three Consecutive Days?

This scenario is commonly associated with the common cold—particularly upper respiratory tract infections caused by bacterial or viral pathogens—which may result in prolonged low-grade fever. In such cases, it is advisable to consult a physician to identify the specific infectious agent and initiate targeted anti-inflammatory and antimicrobial therapy to alleviate symptoms. During this period, patients should maintain a light, nutritionally balanced diet and avoid spicy, greasy, raw, or cold foods that may irritate the digestive system.

Common infectious causes of low-grade fever include bacterial infections, viral infections, tuberculosis, and infections caused by mycoplasma or chlamydia. Non-infectious conditions may also contribute—for example, rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, and ankylosing spondylitis. Management should focus on both symptom control and addressing the underlying etiology.

Additionally, indoor air should be kept fresh and well-ventilated, with appropriate temperature and humidity levels. Other non-infectious factors—including hyperthyroidism, connective tissue disorders, peptic ulcer disease, or malignancies—may also lead to persistent low-grade fever. Therefore, patients are strongly advised to undergo thorough evaluation to determine the precise cause and receive condition-specific treatment.

The above outlines potential causes of persistent low-grade fever lasting three consecutive days. We hope this information is helpful to you.