Pain in your lower right abdomen has several possible causes, but the most important one to rule out first is appendicitis. That’s because a burst appendix can become life-threatening within hours. Other common causes range from kidney stones and ovarian cysts to muscle strain and inguinal hernias, and telling them apart often comes down to how the pain started, what it feels like, and what other symptoms you have.
Appendicitis: The First Thing to Rule Out
Appendicitis is the most common surgical emergency involving the lower right abdomen, and it follows a recognizable pattern. The pain typically starts around your belly button as a vague, dull ache. It may hover there or come and go for several hours. Then nausea and vomiting develop. After that wave passes, the pain shifts down and to the right, becoming sharper and more focused. This migration from the center of your belly to the lower right side is the hallmark progression.
The spot where appendicitis pain concentrates is called McBurney’s point, roughly two inches inward from the bony hip projection toward your belly button. Pressing on that area and then quickly releasing your hand often triggers a sharp stab of pain (called rebound tenderness). Walking, coughing, or riding over bumps in a car can make the pain worse. If your pain follows this pattern, especially if it’s been steadily worsening over 12 to 24 hours, get to an emergency room. A CT scan can detect appendicitis with about 97% accuracy.
Kidney Stones
A stone stuck in the right ureter (the tube connecting your kidney to your bladder) can cause intense pain in the lower right abdomen that radiates from your back or side down toward your groin. The pain tends to come in waves, building to a peak and then easing before returning. Unlike appendicitis, kidney stone pain rarely stays in one spot. It shifts as the stone moves.
The giveaway is usually urinary symptoms: blood in your urine (even just a pink tinge), burning when you pee, feeling like you constantly need to go, or cloudy, foul-smelling urine. Nausea and vomiting are common with both kidney stones and appendicitis, so the urinary symptoms are what help distinguish the two. Fever or chills alongside these symptoms can signal an infection behind the blockage, which needs urgent treatment.
Ovarian Cysts and Ovarian Torsion
If you have ovaries, a cyst on the right ovary is a frequent cause of lower right abdominal pain. Most ovarian cysts form during your menstrual cycle and resolve on their own without you ever knowing they were there. But when a cyst grows large or ruptures, the pain can be sudden and severe, sometimes with internal bleeding that causes lightheadedness.
A large cyst also raises the risk of ovarian torsion, where the weight of the cyst causes the ovary to twist on itself. Torsion cuts off blood flow to the ovary and causes sudden, intense pelvic pain with nausea and vomiting. It can feel almost identical to appendicitis. The key difference is that torsion pain often starts abruptly during physical activity or after a sudden movement, while appendicitis builds gradually over hours. Torsion is a surgical emergency because the ovary can be permanently damaged if blood flow isn’t restored quickly.
Ectopic Pregnancy
For anyone of childbearing age, an ectopic pregnancy should be considered whenever lower abdominal pain occurs alongside a missed period or vaginal bleeding. An ectopic pregnancy happens when a fertilized egg implants outside the uterus, most commonly in a fallopian tube. If the right tube is involved, the pain localizes to the lower right side.
Diagnosis involves a combination of ultrasound and tracking levels of a pregnancy hormone called beta-hCG. In a normal early pregnancy, this hormone rises by at least 49% over 48 hours. A slower rise, or a small decrease of less than 21% over two days, raises concern for an ectopic pregnancy. This is a time-sensitive diagnosis because a growing ectopic pregnancy can rupture the fallopian tube, causing dangerous internal bleeding.
Inguinal Hernia
Inguinal hernias occur when tissue pushes through a weak spot in the lower abdominal wall near the groin. They’re far more common in men and often appear as a visible or palpable bulge. The pain tends to be more of an aching heaviness than a sharp stab, and it has a clear relationship to physical strain: lifting, coughing, or standing for long periods makes it worse, while lying down brings relief. In men, the bulge can extend into the scrotum.
A hernia that can be gently pushed back into the abdomen is generally not an emergency. But if the bulge becomes firm, painful, and won’t go back in, the trapped tissue may be losing its blood supply. That situation, called a strangulated hernia, requires emergency surgery.
Crohn’s Disease
Crohn’s disease is a chronic inflammatory condition that affects the gut, and in roughly 80% of cases, the inflammation centers on the last section of the small intestine, which sits in the lower right abdomen. During a flare, Crohn’s can mimic appendicitis closely enough that some people are only diagnosed after being taken to surgery for a suspected appendix problem.
What sets Crohn’s apart is its chronic, recurring nature. You’ll typically have weeks or months of diarrhea (sometimes bloody), cramping abdominal pain, fatigue, and unintended weight loss. The pain may come and go over time rather than following the steady escalation of appendicitis. Complications like abscesses, narrowing of the intestine, and abnormal connections between sections of bowel can develop if the disease goes untreated.
Swollen Lymph Nodes in the Abdomen
In children and teenagers especially, a condition called mesenteric lymphadenitis can closely mimic appendicitis. It happens when lymph nodes in the tissue connecting the intestines become inflamed, usually after a viral infection like a stomach bug or upper respiratory illness. The pain is often on the lower right side but tends to be more spread out than the focused tenderness of appendicitis. Fever, nausea, vomiting, and diarrhea can all accompany it.
The important distinction is that mesenteric lymphadenitis typically clears up on its own within a few days to weeks, while appendicitis gets progressively worse. If a child recently had a cold or stomach virus and then develops right-sided belly pain with a low-grade fever, this is a likely culprit, but imaging is often still done to rule out appendicitis.
How Doctors Figure Out the Cause
A CT scan is the gold standard for evaluating lower right abdominal pain in adults. It detects appendicitis with a sensitivity of about 97% and a specificity of 96%, meaning it catches nearly all true cases while rarely producing false alarms. Contrast-enhanced CT (using both IV and oral contrast) performs best, with sensitivity above 99%. Ultrasound is less accurate overall (about 82% sensitivity for appendicitis) but is the preferred first-line imaging for children, pregnant individuals, and anyone being evaluated for ovarian problems, because it avoids radiation exposure.
Beyond imaging, blood work showing elevated white blood cells and inflammatory markers helps confirm whether something infectious or inflammatory is going on. For women of childbearing age, a pregnancy test is a routine part of the workup regardless of whether pregnancy seems likely.
Symptoms That Need Emergency Care
Lower right abdominal pain warrants an ER visit if you notice any of the following:
- Severe pain that makes it hard to stand, walk, or find a comfortable position
- Escalating pain that started mild and has been steadily worsening over hours
- Fever or chills alongside the pain
- Vomiting blood or shortness of breath
- Blood in your urine or stool
- Pain spreading upward toward your chest, neck, or shoulder
- Yellowing skin or eyes
Pain that comes and goes mildly over days or weeks is less likely to be an emergency but still deserves a medical evaluation, especially if it’s accompanied by changes in bowel habits, unexplained weight loss, or fatigue.