Chronic low grade fever

What is a low grade fever?

Fever means that the body temperature is above what is considered normal. Fever is actually one of the most common health complaints in the world, since it activates as soon as there is something wrong inside the body. A fever is the body’s natural defensive mechanism, a part of the immune response to foreign agents; microorganisms like bacteria and viruses.

A fever is not just any elevated body temperature. It is often accompanied by the bouts of cold or chills, increased heart rate and muscle tone, as well as fatigue.

The experts do not seem to agree on any single normal body temperature, and we now know that there's a normal range rather than any single normal number (See: Why is my body temperature fluctuation so much? for more information), but it is safe to say that 98°F is considered by most to be normal. Anything above that is typically considered an elevated body temperature.

Low grade fever is a body temperature of 100.4°F to 102.2°F. This fever is persistent in nature, it can go on for quite a while, during which time a person does not necessarily have to experience chills and fatigue.

Causes of chronic low grade fever

Sometimes a low grade fever is a sign of an mild infection passing through the body, being fought off by the immune system. However, if it persists, it is considered chronic low grade fever. There are many conditions that can cause chronic low grade fever. It is important to realize that low grade fever alone is not a sign of any of those diseases and conditions, unless there are other symptoms as well.

Rubella, measles and mumps are infectious diseases that cause swelling and inflamed salivary glands, as well as low grade fever. Chickenpox, characterized by red rash, also causes low grade fever.

Low grade fever can also result from wound infection, bacterial infections such as scarlet fever, strep throat and others.

Viral infections and viral diseases also cause low grade fever. Those conditions may include mononucleosis, hepatitis, flu, common cold, as well as serious diseases like HIV/AIDS, chikungunya, dengue fever and such.

Low grade fever may indicate tuberculosis, pelvic inflammatory disease, leukemia, rheumatoid arthritis, typhoid, myositis, allergies, chronic sinusitis, chronic abscess and a wide range of autoimmune diseases.

Certain medications, including some antibiotics, can also induce an elevated body temperature. 

In infants, a low grade fever may well be a sign of teething, or the upcoming eruption of new milk teeth. 

Finally, it's good to know that intense psycholigical stress may also induce low grade fevers, and if the stress is itself chronic, this can mean that a person's temperature stays increased for a long time as well.

Low grade fever with no other symptoms is one of the most difficult symptoms to diagnose and treat, because it can obviously be linked with so many conditions and diseases, making it very hard to pinpoint a specific one. However, if other symptoms are present, doctors can diagnose the problem more easily and quickly. In order to make the diagnosis, doctors will not rely only on physical exam and will order a wide range of tests.