A cyst is a non-cancerous, closed sac that forms within the body’s tissues, containing a distinct membrane and usually filled with fluid, pus, or other semi-solid material. While most simple cysts are painless and go unnoticed, their presence can sometimes lead to a systemic reaction. The direct answer to whether a cyst can cause a fever is yes, but this symptom indicates the cyst has progressed into a more serious condition.
How Cysts Lead to Fever
Fever develops when the cyst becomes compromised, allowing bacteria to enter the sac and triggering a massive immune response. This contamination often transforms the cyst into a painful, pus-filled abscess, representing a localized infection. When bacteria colonize the cyst’s contents, the body dispatches white blood cells to the site. This releases inflammatory molecules called cytokines into the bloodstream. These cytokines travel to the brain’s hypothalamus, which acts as the body’s thermostat, causing it to reset at a higher temperature. If the infection is severe or the abscess is large, the number of circulating inflammatory markers increases substantially, leading to a higher fever and systemic illness.
Recognizing Signs of Cyst Infection
The onset of fever is accompanied by localized and systemic symptoms indicating an infection. Locally, the area around the cyst exhibits pronounced inflammation, becoming visibly red and warm to the touch. The cyst itself becomes significantly more painful and tender, often developing a throbbing sensation as pressure builds. It may also swell rapidly and, in some cases, spontaneously drain a thick, foul-smelling discharge (pus). Systemic symptoms include generalized malaise, fatigue, body aches, and chills.
Specific Types of Cysts That Become Infected
Certain types of cysts are more susceptible to infection and resulting fever due to their location or contents. Pilonidal cysts, which form near the tailbone, often involve trapped hair and debris, creating an environment for bacterial growth. An infected pilonidal cyst rapidly progresses to a painful abscess, making fever a common symptom.
Epidermoid cysts, which are skin cysts filled with keratin, can become infected if the lining is breached, such as by squeezing or a break in the skin. These cysts quickly become tender, swollen, and red, leading to a fever that signals the need for treatment. Bartholin’s cysts, located near the vaginal opening, also frequently become infected due to their proximity to high-bacteria areas, easily forming a painful abscess that causes localized swelling and fever.
A fever associated with an ovarian cyst usually signals a complication, such as a rupture or ovarian torsion, where the ovary twists and cuts off its blood supply. In this case, the fever is a reaction to the internal inflammation or tissue damage, rather than a direct bacterial infection of the cyst itself.
When to Seek Medical Attention
Any fever that develops alongside a known cyst should be treated as a medical urgency, signifying a spreading infection or serious internal complication. Seek immediate medical attention if your temperature rises above 100.4°F (38°C). Further warning signs include rapidly increasing pain, red streaking extending from the cyst site, or signs of shock like dizziness and a rapid heart rate. Medical intervention typically involves diagnostic imaging to confirm the extent of the abscess and rule out deeper complications. Treatment usually consists of antibiotics and, most often, an incision and drainage procedure to relieve pressure and remove the pus. Do not attempt to drain an infected cyst at home, as this can force bacteria deeper into the tissue and worsen the systemic infection.