Persistent Low-Grade Fever and Its Possible Causes

Slightly elevated body temperature over a prolonged period?

Hello Doctor, I have been experiencing slightly elevated body temperature since before my vacation, particularly feeling uncomfortable when it reaches around 37.5 to 37.8 degrees Celsius, while my usual temperature is about 36.9 to 37.2 degrees.
I also have symptoms resembling dizziness due to lack of oxygen, and sometimes I have a reduced appetite.
Recently, I've been experiencing dry mouth and throat, which can become severe enough to wake me up at night, and drinking water doesn’t seem to help much.
Over the past month, I have visited various specialists, including ENT, urology, infectious diseases, and gastroenterology.
Initially, the ENT specialist diagnosed me with a urinary tract infection, and I thought I would be fine after taking the medication, but my temperature has remained above 37 degrees.
When I visited the infectious disease specialist, blood tests indicated an issue with one of my immune-related values, but I didn’t note the exact name; I only remember that the standard value was either 160 or 1600.
During my visit to the infectious disease specialist, I also had my weight measured, and I have lost 6 kilograms over the past six months since my last measurement.
Recently, I have been experiencing a scratchy and swollen throat, and this morning when I visited the ENT specialist, the doctor suggested it might be due to allergies.
I would like to ask if the slightly elevated body temperature could be related to my immune system.
I haven’t yet seen an immunologist, and I have been very worried about not being able to find the cause of my elevated temperature during this time.
I’m not sure which other specialty I should consult.
I hope the above description can help deduce possible causes.
Thank you very much, Doctor, for your assistance.

Niming, 10~19 year old female. Ask Date: 2020/03/01

Dr. Gao Jiankai reply Internal Medicine

Hello, thank you for your message.
If you are experiencing unexplained elevated body temperature or mild fever and have already consulted the specialties mentioned in your message without finding a solution, it would indeed be advisable to visit a Rheumatology and Immunology department to evaluate potential immune function issues.
When you visit the Rheumatology and Immunology department, please remember to inform the physician about your symptoms of dryness affecting your sleep.
This will help them narrow down the scope of examinations and potentially expedite the identification of the problem.
The Allergy, Immunology, and Rheumatology Department at Changhua Hospital, Ministry of Health and Welfare, is here to support you.

Reply Date: 2020/03/01

More Info

Persistent low-grade fever can be a perplexing and concerning symptom, especially when accompanied by other symptoms such as dizziness, decreased appetite, and dryness in the throat. Your experience of having a temperature ranging from 36.9 to 37.8 degrees Celsius, along with the sensation of dizziness akin to hypoxia, suggests that there may be underlying issues that need to be addressed.

Firstly, it is important to understand that a low-grade fever, defined as a body temperature between 37.2 and 38.3 degrees Celsius, can arise from a variety of causes. These can include infections (both acute and chronic), inflammatory conditions, autoimmune disorders, and even malignancies. In your case, the initial diagnosis of a urinary tract infection (UTI) could have been a contributing factor to your symptoms, but the persistence of the fever after antibiotic treatment raises the question of whether there are other underlying issues at play.

The mention of an abnormal immune marker during your blood tests is particularly noteworthy. While you did not capture the exact name of the marker, the value you referenced (160 or 1600) suggests that there may be an autoimmune component or an ongoing inflammatory process. Autoimmune diseases, such as lupus or rheumatoid arthritis, can manifest with persistent low-grade fevers, fatigue, and other systemic symptoms. It would be prudent to follow up with an immunologist or a rheumatologist to further investigate this aspect.

Additionally, the symptoms of throat dryness and itchiness could indicate an allergic reaction or an environmental factor contributing to your discomfort. Allergies can cause systemic symptoms, including low-grade fever, especially if there is an underlying allergic rhinitis or sinusitis. It may be beneficial to explore allergy testing or consult an allergist to rule out this possibility.

Weight loss, as you mentioned, is another critical factor to consider. A 6-kilogram weight loss over six months warrants further investigation, as it can be indicative of a chronic illness or a metabolic disorder. It is essential to assess your nutritional intake, stress levels, and any changes in lifestyle that may have contributed to this weight loss.

Given the complexity of your symptoms and the various specialists you have consulted, it may be beneficial to adopt a more integrative approach. Consider keeping a detailed symptom diary that tracks your temperature, dietary habits, stress levels, and any other relevant factors. This information can be invaluable when discussing your case with healthcare providers.

In conclusion, persistent low-grade fever can stem from a multitude of causes, including infections, autoimmune disorders, allergies, and metabolic issues. It is crucial to continue seeking answers through thorough medical evaluations and possibly revisiting specialists who can provide insights into your immune system's status. Do not hesitate to advocate for yourself and request further testing or referrals as needed. Your health is paramount, and understanding the root cause of your symptoms is essential for effective treatment and management.

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