AS Symptoms - Mild Fever

Spondyloarthritis (SpA), including ankylosing spondylitis (AS), is a group of chronic arthritis conditions that cause inflammation in the joints. Each person with SpA can have a different set of symptoms, or presentation, of the disease. In addition to the joint symptoms, people with SpA can have extra-articular (beyond the joint) symptoms, including eye inflammation (uveitis), skin rash, and fever.¹

Symptoms of AS often begin in late adolescence or early adulthood (before age 45), although some people experience the onset of symptoms later in life or in childhood. A mild fever may be an early symptom of AS. The most common symptom of early AS is low back pain and stiffness, which is worse in the morning (after a night's sleep) or after periods of inactivity and improves with movement or a warm shower. Other early symptoms may include fatigue, pain in the neck, or heel pain.²

Getting a diagnosis of ankylosing spondylitis can be challenging

Diagnosing AS and other forms of SpA is not a simple or straightforward process. On average, it can take 8-11 years from when symptoms begin to when a person receives a diagnosis.³ One of the reasons diagnoses in the early stages can be so challenging is that early signs, like low back pain or fever, are common and can be caused by a variety of other conditions. If a person's only symptom is a mild fever, doctors may not suspect SpA, as SpA is typically known for joint inflammation. It can be very challenging for a diagnosis of SpA to be made when patients only have non-joint (non-articular) symptoms.¹

Does ankylosing spondylitis cause fever, and why?

The inflammatory response is the immune system's natural reaction when cells are stressed or damaged, or when there is a foreign invader (like a viral, fungal, or bacterial infection). Although inflammation in AS is viewed as having negative consequences, it is a necessary process in the body to recruit defense systems, remove damaged or diseased cells, and trigger repair mechanisms.⁴

The inflammatory response causes a cascade of chemicals to be released in the body. Some of these chemical processes can cause a fever, an increase in the body's temperature. During a fever, the skin may appear pale and an individual may experience shivering. Despite the internal temperature of the body being raised during a fever, the individual may feel chilled. Fevers can also cause the body to sweat, which cools the skin as it evaporates. There are a number of conditions that can cause the body to have a fever, including infections, some types of blood cancer, and chronic conditions like Crohn's disease, a type of inflammatory bowel disease.⁴

In some cases, the pattern of temperature changes in a fever can help doctors determine the cause of the fever. For example, a continuous fever over 100.⁴ degrees Fahrenheit can indicate a viral or bacterial infection. A fever that may occur with SpA is a mild fever and may be initially classified as a fever of unknown origin. Fevers of unknown origin generally last more than three weeks. These types of fevers may also be caused by cancers, certain infections, and autoimmune diseases.⁵

Managing fever

Generally, fevers are treated with non-steroidal anti-inflammatory drugs (NSAIDs), which are available over-the-counter. Common NSAIDs used for fever include aspirin and ibuprofen. NSAIDs can help relieve the symptoms of a fever and help bring the body temperature down.⁶