What Causes Appendicitis?

Appendicitis is inflammation of the appendix, a tube-shaped tissue attached to the large intestine. A blockage within the appendix resulting in inflammation is the primary cause of appendicitis. Several factors, including impacted stool and swollen lymph nodes, can cause this blockage. Genetic factors may also contribute to appendicitis.

This article will explore the cause and potential risk factors of appendicitis. It will also discuss the early warning signs of appendicitis and the symptoms of a ruptured appendix.

What Is the Main Cause of Appendicitis?

The main cause of appendicitis is an obstruction within the lumen of the appendix. The appendix lumen is the space inside of the appendix that connects to and empties into the large intestine.

The obstruction may be caused by one of the following:

• Fecalith (hard, rock-like stool)
• Appendicolith (calcified deposit of stool)
• Swollen lymphatic tissue
• Scarring within the appendix lumen
• Inflammatory bowel diseases, like Crohn's disease (chronic inflammation of the digestive tract)
• Infection by viruses, bacteria, fungi, or parasites 
• Growths in the appendix or large intestine

Abdominal trauma (such as from an injury) has also been linked to appendicitis, although this is rare. Proposed mechanisms include direct compression of the appendix from the traumatic injury or obstruction from the blood pooling within the appendix.

Very rarely, ingesting fruit seeds, or swallowing foreign objects, like a piece of tongue-piercing jewelry, needle, screw, or pin, have been identified as causes of appendicitis.

You Didn’t Cause Your Appendicitis

Rest assured that it's not your fault if you or your child develops appendicitis (with the extreme exception of purposefully ingesting a foreign object).

Even with increased tension, worry, or anxiety at school, work, or home, no proven evidence exists that acute stressors directly cause appendicitis.

Long-term stress may affect your gut health and immune system functioning, theoretically increasing your risk for appendicitis. Still, this connection between chronic stress and appendicitis is not scientifically proven and needs further investigation.

The same ambiguity goes for diet. While research suggests a diet low in fiber may make a person more vulnerable to developing appendicitis, no direct link has been found. Further research is required.

Who Is at an Increased Risk of Getting Appendicitis? 

Appendicitis is most common in people between 10 and 30 years old.

Appendicitis can occur in children, although it rarely occurs in babies and children younger than 5 years old. Appendicitis becomes more common in school-aged children, and occurrence peaks in the late teens.

Even though it's not common, older adults can also develop appendicitis. That said, appendix rupture is more frequent in older individuals.

Appendicitis happens slightly more often in males than females. A male in the United States has a lifetime risk for developing appendicitis of 8.6%, whereas a female's lifetime risk is 6.7%. (Note that while Verywell Health aims to use inclusive language, when citing a health authority or research, the terms for sex or gender from that source are used.)

Besides age and sex, the following factors can possibly increase your risk of developing appendicitis:

• Low fiber and high sugar intake
• Decreased water intake
• Exposure to air pollution, allergens, or cigarette smoke
• Digestive tract infections
• Having a family history of appendicitis

Some studies have also found a higher incidence of appendicitis in the summer months. Experts suspect that warmer weather could increase a person's risk for dehydration, a poorer diet, and exposure to infectious digestive illnesses ("stomach flu"), allergens, and air pollution.

Is Appendicitis Genetic?

Genetic factors may play a role in the development of appendicitis. Scientists are starting to explore and identify possible gene mutations (changes in DNA) that may be involved.

This role of genetics is supported by the fact that if you have a family history of appendicitis, your risk of getting appendicitis increases. This risk increases the more family members you have with such a history.

Older studies have found that a family history of acute appendicitis increased the odds of acute appendicitis twofold to threefold, including in children.

Is Appendicitis Rare or Common?

Appendicitis is one of the most common causes of acute (sudden and significant) abdominal pain in adults and children.

Every year in the United States, appendicitis is diagnosed in around 250,000 people. Moreover, appendicitis is also a worldwide health concern. In 2019, there were 17.7 million new cases of appendicitis globally.

All said, while appendicitis is a common cause of acute abdominal pain, many health conditions can mimic it. Examples include stomach flu and diverticulitis (infection of a pouch in your colon lining).

Preventing Appendicitis Isn’t Always in Your Control

There is no surefire way to prevent appendicitis.

Eating a fiber-rich diet may be a helpful preventive strategy, although experts aren't sure why. Fiber-rich foods promote healthy gut bacteria, which might minimize appendix inflammation.

A high-fiber diet is rich in fruit and vegetables. Apples with skin, prunes, peas, and green beans are exceptionally high in fiber. Beans and breakfast cereals are other good fiber sources.

Early Warning Signs of Appendicitis

Abdominal pain is the most common early warning sign of appendicitis.

The pain is typically felt around the navel (belly button) before moving to the lower right side of the abdomen.

The movement of pain classically occurs over 12 to 24 hours. How badly it hurts will vary. The pain may be mild and intermittent to start before becoming sharp, severe, and constant.

Other appendicitis early warning symptoms include:

• Nausea or vomiting
• A change in bowel habits (e.g., diarrhea or constipation)
• Loss of appetite
• Low-grade fever

Seeking medical attention immediately if you are experiencing appendicitis symptoms is essential.

An inflamed appendix can rupture, generally within 48 to 72 hours after symptoms begin, although sometimes sooner. When the appendix ruptures, an abscess (pocket of pus/bacteria) or peritonitis (a life-threatening infection of the abdominal lining) may develop.

Summary

The leading cause of appendicitis is a blockage within the appendix. Many factors, including impacted stool, swollen lymph nodes, foreign objects, or a digestive tract infection, may cause this blockage.

A family history of the disease can also increase your risk for appendicitis. While there is no definitive way to prevent appendicitis, prompt diagnosis and treatment can lower your risk for appendix rupture and complications.