Endometriosis is a condition where tissue resembling the uterine lining grows outside the uterus, often in the pelvic region. This misplaced tissue responds to hormonal changes, causing bleeding and irritation within the abdominal cavity. While many symptoms are associated with this chronic condition, a common question is whether it can directly cause a fever. A high, systemic fever is not a typical symptom of the primary disease, but the underlying biological processes and rare complications can lead to temperature elevation.
Endometriosis and the Inflammatory Response
Endometriosis lesions, which are patches of tissue growing outside the uterus, create chronic, localized inflammation within the pelvis. These lesions shed and bleed during the menstrual cycle, causing irritation to surrounding tissues and organs. This continuous inflammatory process triggers the immune system to release signaling molecules called cytokines into the surrounding fluid and bloodstream.
This heightened immune activity can sometimes result in a low-grade temperature elevation, typically below 100.4°F (38°C). This is a distinct physiological reaction from the high-grade fever that signals an acute, systemic infection. Many people with endometriosis report feeling flu-like symptoms, sometimes called “period flu,” during a flare-up. This low-grade increase is a consequence of the ongoing inflammation, not a sign of a full-blown infectious fever.
Acute Complications That Lead to High Fever
Although endometriosis rarely causes a high fever, the condition can lead to acute complications resulting in a significant temperature spike above 100.4°F (38°C). A high fever is a serious warning sign, typically indicating a secondary medical emergency requiring immediate attention. One such complication is the rupture of an endometrioma, a cyst filled with old blood that forms on the ovary.
If an endometrioma bursts, the contents spill into the pelvic cavity, causing severe pain and an intense inflammatory reaction known as peritonitis. This event can quickly lead to infection and a high fever. Another serious issue is the formation of a pelvic abscess, a localized collection of pus caused by a bacterial infection. This infection can develop near endometrial implants and trigger a high, sustained fever and chills.
In rare cases, deep-infiltrating endometriosis can affect other organ systems, leading to severe secondary infections. Tissue growths can press on the ureters, the tubes that carry urine from the kidneys to the bladder, obstructing flow. This obstruction can cause urine to back up, leading to a severe kidney infection, or pyelonephritis, which commonly presents with a high fever, back pain, and significant illness. In these scenarios, the fever is a symptom of the acute infection or complication, not the primary endometriosis disease process.
Other Illnesses That Co-Occur with Endometriosis
When someone with endometriosis develops a high fever, it is often due to a common illness or infection unrelated to their underlying condition. Since fever is a general symptom of many different ailments, it should not be automatically attributed to an endometriosis flare-up. A high temperature may simply be a sign of a common viral infection, such as influenza or a cold, or a bacterial infection that anyone could contract.
A fever can also arise from a co-occurring gynecological or urinary condition. Urinary tract infections (UTIs) are frequent, and their pain can be confused with the pelvic pain of endometriosis. Furthermore, Pelvic Inflammatory Disease (PID) can occur, and this condition, which is different from endometriosis, is characterized by pelvic pain, discharge, and a noticeable fever. Attributing a fever to endometriosis without medical consultation risks missing the correct diagnosis and delaying treatment for a potentially serious, separate infection.
When to Contact a Healthcare Provider
A high fever, typically 100.4°F (38°C) or higher, should never be ignored, especially when it occurs alongside severe pelvic pain. This combination of symptoms is a red flag that points to an acute complication, such as a ruptured cyst or a serious infection. Other signs warranting immediate medical attention include severe nausea, persistent vomiting, fainting, or sudden, excruciating abdominal pain that is much worse than typical flare-up pain.
Determining the source of the fever is necessary, as it usually signals a distinct issue or complication requiring specific treatment, such as antibiotics or emergency surgery.