Cysts cause pain through several distinct mechanisms: pressure on nearby nerves, inflammation of surrounding tissue, and in some cases, rupture or twisting that triggers sudden, severe pain. A small cyst often causes no discomfort at all, but once it grows large enough to press against nerves, organs, or other structures, the pain can range from a dull ache to something sharp and debilitating.
Pressure and Nerve Compression
The most common reason a cyst hurts is simple mechanical pressure. As a cyst fills with fluid or semi-solid material, it expands and pushes against whatever surrounds it. When that happens to include a nerve, the result is pain, numbness, tingling, or weakness in the area the nerve supplies. A ganglion cyst on the wrist, for example, can compress the median nerve and cause carpal tunnel symptoms, or press against a tendon sheath and trigger a finger that catches when you bend it. Patients with wrist ganglions often report pain and tenderness that gets worse with movement because the cyst shifts position and creates friction against tendons and joint surfaces.
Baker’s cysts behind the knee follow the same principle. The tibial nerve sits close to the surface in the back of the knee, making it especially vulnerable. A large Baker’s cyst can compress this nerve and cause pain, numbness, or weakness radiating down the lower leg. In rarer cases, the cyst presses on the popliteal artery deeper in the knee, restricting blood flow and causing cramping pain with walking.
This pressure-based pain tends to build gradually. You might notice it only during certain movements at first, then find it becoming constant as the cyst enlarges.
Inflammation and Infection
Not all cyst pain comes from pressure alone. The cyst wall itself can become inflamed, triggering the body’s immune response and flooding the area with chemicals that activate pain receptors. This is why an inflamed cyst feels hot, swollen, and tender to the touch even if it hasn’t grown much larger.
When bacteria enter the picture, the pain escalates dramatically. An infected cyst essentially becomes an abscess: a red, swollen, pus-filled pocket that throbs and hurts even at rest. The key difference between a cyst and an abscess is speed and severity. A cyst grows slowly and is usually painless until it reaches a certain size. An abscess develops quickly, causes intense pain almost immediately, and can produce symptoms beyond the local area, like fever and fatigue. Skin cysts, Bartholin’s cysts near the vaginal opening, and dental cysts are all prone to infection, and the shift from mild discomfort to sharp, constant pain can happen within days.
What Happens When a Cyst Ruptures
A ruptured cyst can cause some of the most intense pain people experience. The reason goes beyond just the tearing of the cyst wall. When a cyst breaks open, its internal contents spill into surrounding tissue, and those contents are often chemically irritating. Dermoid cysts, for instance, contain sebaceous material (a waxy, oily substance) and sometimes hair fragments. If this material leaks into the abdominal cavity, it can cause chemical peritonitis, a painful inflammatory reaction across the lining of the abdomen.
Ovarian cyst rupture is one of the most common scenarios. The pain is typically sudden and severe, often on one side of the pelvis, and may come with nausea and vomiting. If the cyst was filled with blood (a hemorrhagic cyst), rupture can also cause internal bleeding, which adds to the pain and can become a medical emergency.
Ovarian Torsion: The Most Severe Scenario
Ovarian cysts create a unique risk that cysts elsewhere in the body don’t: torsion. This happens when the weight of a cyst causes the ovary to twist on the ligaments that hold it in place, cutting off its blood supply. The fallopian tube often twists along with it.
The sequence is predictable and escalating. First, the veins draining blood away from the ovary get pinched, causing the ovary to swell with trapped blood. Then, as swelling increases, the arteries bringing fresh blood in get compressed too. Without blood flow, the ovarian tissue begins to die. This process produces severe, often one-sided pelvic pain that can be sharp or dull, constant or coming in waves. Nausea and vomiting are common. Left untreated, torsion can lead to permanent loss of the ovary, hemorrhage, and infection of the abdominal lining.
Torsion is most likely with larger cysts because their extra weight makes the ovary more prone to rotating. Sudden changes in position or physical activity can be the trigger.
Why Pain Gets Worse Over Time
A cyst that’s been present for weeks or months can gradually sensitize the surrounding nerves, making the area more reactive to pain than it would normally be. Chronic irritation causes sensory nerve fibers in the area to sprout and multiply, effectively turning up the volume on pain signals. This is why a cyst that was mildly uncomfortable for months can start to feel significantly more painful even without a dramatic change in size. The cyst hasn’t necessarily gotten worse; your local pain-sensing system has become more efficient at detecting it.
This also explains why some people report lingering tenderness even after a cyst is drained or removed. The nerve sensitization takes time to reverse.
When Cyst Pain Signals Something Serious
Most cyst pain is manageable and resolves with treatment or on its own. But certain patterns indicate something more urgent is happening. An ovarian cyst is more likely to cause significant pain if it becomes large, bleeds, breaks open, interferes with blood supply to the ovary, or causes the ovary to twist. Sudden, severe pelvic pain with nausea and vomiting is the hallmark of torsion or rupture with internal bleeding, both of which need prompt evaluation.
For cysts anywhere on the body, rapidly increasing pain, redness, warmth, and swelling suggest infection. A cyst that was stable for months but suddenly becomes exquisitely tender has likely become inflamed or infected and needs attention sooner rather than later.
What Pain Relief Looks Like
For cysts that are simply causing pressure-related discomfort, treatment focuses on either shrinking or removing the cyst. Many ovarian cysts resolve on their own within one to three menstrual cycles. Ganglion cysts sometimes shrink if the joint is rested. When they don’t resolve, aspiration (draining the fluid with a needle) or surgical removal are the standard options.
For infected cysts or abscesses, incision and drainage provides the most immediate relief. Pain and discomfort after the procedure are normal for about a week as the tissue heals, but the intense throbbing pain of the infection itself typically drops significantly once the pressure is released. Warm compresses and over-the-counter pain relief can bridge the gap for mild to moderate cyst pain while you’re waiting for a procedure or monitoring whether the cyst resolves on its own.