What causes persistent low-grade fever in adults?

Persistent low-grade fever in adults is a very common phenomenon in daily life. If such a low-grade fever persists over a prolonged period, it may lead to certain complications. There are numerous potential causes of persistent low-grade fever in adults—so what exactly accounts for this condition?

What Causes Persistent Low-Grade Fever in Adults?

1. Post-infectious low-grade fever

Observed in a minority of patients following recovery from acute infectious diseases, this type of low-grade fever may persist for several weeks and is associated with incomplete restoration of thermoregulatory center function.

2. Streptococcal infection

A sustained low-grade fever may occur after upper respiratory tract infection. Laboratory tests often reveal elevated antistreptolysin O (ASO) titers and an increased erythrocyte sedimentation rate (ESR). Treatment typically includes penicillin combined with low-dose corticosteroids.

3. Organic low-grade fever

Examples include tuberculous low-grade fever. Chronic infectious foci—such as those in the sinuses, tonsils, liver/biliary system, or urinary tract—may also cause persistent low-grade fever. Other conditions—including hyperthyroidism, connective tissue disorders, malignancies, and leukemia—can likewise present with sustained low-grade fever. During episodes of low-grade fever, it is advisable to drink ample warm water to replenish body fluids and promote metabolism, since elevated body temperature significantly increases fluid loss. To prevent dehydration, timely fluid replacement is essential.

In daily life, individuals should also engage in regular physical exercise, consume more fresh fruits and vegetables, and drink plenty of warm water—these habits support healthy metabolism and facilitate the elimination of toxins from the body. Additionally, personal hygiene must be maintained; hands should be washed before meals to prevent pathogen entry and subsequent illness. We hope this information proves helpful to you.