Persistent Low-Grade Fever: Causes and When to Seek Help

Low-grade fever issue

Hello Doctor, I remember that about five or six years ago, I experienced episodes for a few months where I would feel warm and have headaches (my temperature was always between 36-37.5°C without fever).
Since then, I have had similar experiences every year.
I undergo routine health check-ups annually, including blood and urine tests, abdominal ultrasound, and chest X-rays, and everything has been normal.
Last August, I had an endoscopy that showed mild gastritis.

Recently, over the past two to three months, I have noticed that I feel warm about twice a month (still without fever, around 36°C).
Today is the third day I have felt this way, and this afternoon, my ear temperature reached a maximum of 37.9°C, but after lying down, it dropped to 37.5°C.
I consulted with a gynecologist, and it doesn't seem to be related to premenstrual temperature changes.
I also do not have any other cold symptoms.
However, I have been feeling more anxious and a bit fatigued in recent days.

Could you please advise if I might have any underlying condition? What tests should I consider? I feel worried and tense.
Thank you!

Amy, 30~39 year old female. Ask Date: 2022/04/20

Dr. Liao Yaopan reply Family Medicine

Hello, with unexplained fever and elevated body temperature, the primary concern should be to rule out any potential infectious issues.
If such concerns are excluded, differential diagnosis for autoimmune rheumatic diseases and even neoplastic conditions should be considered.
Please note that online consultations are not equivalent to in-person visits and cannot provide diagnoses or treatment recommendations.
Changhua Hospital cares about you.

Reply Date: 2022/04/20

More Info

Persistent low-grade fever can be a perplexing and concerning symptom, especially when it lasts for an extended period without a clear diagnosis. In your case, you've experienced episodes of feeling warm, headaches, and fluctuating temperatures over the years, with recent spikes reaching up to 37.9°C (100.2°F). While this may not constitute a fever in the traditional sense (which is generally defined as a temperature of 38°C or higher), it can still be indicative of an underlying issue that warrants further investigation.

Possible Causes of Persistent Low-Grade Fever
1. Infections: Chronic infections, such as tuberculosis, endocarditis, or even certain viral infections, can lead to persistent low-grade fevers. These infections may not always present with classic symptoms, making them harder to diagnose.

2. Autoimmune Disorders: Conditions like lupus, rheumatoid arthritis, or other autoimmune diseases can cause prolonged low-grade fevers. These diseases often have a variety of symptoms, including fatigue, joint pain, and skin rashes.

3. Malignancies: Certain cancers, particularly lymphomas or leukemias, can present with low-grade fevers as one of their symptoms. This is often accompanied by other signs such as unexplained weight loss, night sweats, or fatigue.

4. Chronic Inflammatory Conditions: Conditions such as Crohn's disease or ulcerative colitis can also lead to persistent fevers, especially during flare-ups.

5. Medications: Some medications can induce fever as a side effect. If you've started any new medications recently, this could be a factor.

6. Psychogenic Causes: Stress and anxiety can manifest physically, sometimes leading to symptoms like low-grade fever. Your mention of feeling tense and fatigued could suggest that psychological factors might be contributing to your symptoms.

When to Seek Help
Given your history and the persistence of your symptoms, it is advisable to consult with a healthcare professional if you haven't already. Here are some steps you can take:
1. Comprehensive Evaluation: Since you have undergone various tests without a definitive diagnosis, consider seeking a second opinion or consulting a specialist, such as an infectious disease expert or a rheumatologist, who can provide a fresh perspective on your symptoms.

2. Detailed Symptom Diary: Keep a detailed record of your symptoms, including temperature readings, associated symptoms (like headaches or fatigue), and any potential triggers (such as stress or dietary changes). This information can be invaluable for your healthcare provider.

3. Further Testing: Depending on your healthcare provider's assessment, additional tests may be warranted. These could include blood cultures, imaging studies (like a CT scan), or even a biopsy if a malignancy is suspected.

4. Mental Health Support: If stress and anxiety are contributing to your symptoms, consider speaking with a mental health professional. They can help you develop coping strategies and address any underlying issues.

5. Lifestyle Modifications: Ensure you are maintaining a healthy lifestyle, including a balanced diet, regular exercise, and adequate sleep. These factors can significantly impact your overall health and may help alleviate some of your symptoms.

Conclusion
Persistent low-grade fever can be a sign of various underlying conditions, and while it may not always indicate a severe illness, it is essential to approach it with caution. Given your history and the complexity of your symptoms, working closely with healthcare professionals to explore all potential causes is crucial. Remember, your health and well-being are paramount, and seeking help is a proactive step toward finding answers and relief.

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