Appendicitis: Symptoms, Causes & Treatment

Appendicitis is inflammation of the appendix, a small pouch attached to the large intestine, and it most often causes pain in the lower right abdomen along with nausea, vomiting, and fever. It usually develops when the appendix becomes blocked, leading to infection and inflammation.

Appendicitis symptoms often begin with pain around the belly button, which then shifts to the lower right side of the abdomen and gradually becomes more intense. Appendicitis is diagnosed based on symptoms, a physical exam, and tests such as blood work, an ultrasound, or a CT scan.

Appendicitis treatment usually involves surgery to remove the appendix, along with medications such as antibiotics and pain relievers to support recovery. Without prompt treatment, appendicitis can lead to complications like rupture, abscess, and infection, which may become life-threatening.

Appendicitis symptoms

The main symptoms of appendicitis are:

• Abdominal pain and tenderness

• Nausea and vomiting

• Loss of appetite

• Fever

• A general feeling of being unwell

• Diarrhea

• A frequent urge to urinate, in some cases

Symptoms of acute appendicitis usually appear within 24 hours, and pain is one of the earliest and most common signs. During the first few hours, the pain usually starts around the belly button, although in some cases it may affect the whole abdomen.

After about 12 to 48 hours, the pain often moves to the lower right side of the abdomen, where it becomes more severe and more typical of appendicitis, according to the NHS. The pain also tends to get worse when the abdomen is pressed, when coughing, and sometimes when walking.

Symptom quiz

If you’re worried you might have appendicitis, select your symptoms from the list below:

This test is only a tool and does not replace a consultation with a surgeon or your primary care provider.

Confirming a diagnosis

Appendicitis is usually diagnosed by a surgeon or primary care provider based on your symptoms and a physical exam. In many cases, they will also order tests, such as an ultrasound or CT scan, to help confirm the diagnosis.

One way to check for possible appendicitis is to lie on your back and press gently on the lower right side of your abdomen with one hand, then quickly let go. If the pain suddenly gets worse when you release the pressure, it may be a sign of appendicitis.

If appendicitis is suspected, you should go to the emergency room right away so the diagnosis can be confirmed and the right treatment started as soon as possible.

Main tests

The main tests recommended for appendicitis are:

• Complete blood count (CBC): helps measure the number of white blood cells in the blood, which can help confirm the presence of inflammation in the body

• C-reactive protein (CRP) test: a blood test that may be elevated in cases of inflammation and infection

• Abdominal ultrasound: helps identify an inflamed appendix

• Computed tomography (CT scan): allows a more detailed view of appendix enlargement and inflammation

In some cases, the provider may also order other tests, such as a urine test, especially when the symptoms are not typical of appendicitis.

Possible causes

In most cases, appendicitis is caused by a blockage in the appendix, a small part of the large intestine, often due to hardened stool. When this happens, bacteria inside the appendix can multiply, leading to inflammation and infection.

The blockage can also be caused by intestinal parasites or, less commonly, by conditions such as intestinal tumors.

Treatment options

Treatment for appendicitis is usually done with:

1. Surgery

Surgery to remove the appendix, known as an appendectomy, is the main treatment for acute appendicitis. This surgery is often done laparoscopically, which is a less invasive technique and usually helps with recovery after surgery.

2. Medications

Medications such as antibiotics and pain relievers are usually prescribed to support treatment when surgery is done to remove the inflamed appendix.

3. Diet

Diet changes are important after surgery to remove the appendix because they help support bowel function and recovery after the procedure. Especially during the first few days after leaving the hospital, a light and easy-to-digest diet made up mainly of clear liquids is recommended.

Potential complications

The main complications of appendicitis are:

• Appendix perforation: also called suppurative appendicitis, this happens when the appendix ruptures and releases bacteria into the abdomen. Symptoms that may suggest a perforated (burst) appendix include feeling very unwell, a higher fever, abdominal swelling, and shortness of breath.

• Abdominal abscess: this happens when the infection gets worse and causes a buildup of pus around the inflamed appendix.

• Fistula formation: in some cases, appendicitis may lead to a fistula, which is a small channel connecting the inflamed appendix to the skin, especially when there is an abscess.

Complications of appendicitis are more common when treatment is delayed and can put a person’s life at risk. Because of this, if appendicitis is suspected, it is important to seek emergency care as soon as possible for evaluation.

How many days does appendicitis take to get worse?

Appendicitis may take more than two days to progress to complications such as a perforated appendix or abscess formation. However, the risk usually increases with each day that passes without treatment.

Although it is rare, there are milder cases in which inflammation of the appendix becomes persistent or keeps coming back, which is known as chronic appendicitis. In these cases, the condition may progress more slowly.

Is appendicitis during pregnancy dangerous?

Appendicitis during pregnancy is dangerous because the appendix can rupture, spreading bacteria inside the abdomen and causing serious infection for both the pregnant person and the fetus. 

Appendicitis during pregnancy causes the same symptoms, and surgery is typically recommended for treatment. An appendectomy is not generally considered harmful to fetal development.

According to the American College of Obstetricians and Gynecologists (ACOG), medically necessary surgery should not be delayed during pregnancy, regardless of trimester.

A pregnant person with intense and constant right-sided abdominal pain should go to the hospital right away.