Appendicitis is the inflammation of the appendix, a finger-shaped pouch that projects from your colon on the lower right side of your abdomen. Appendicitis causes pain in your lower right abdomen. However, the pain often begins near your belly button, then moves lower. Appendicitis usually requires prompt surgery to remove the appendix before it ruptures. The appendix doesn’t seem to have a specific purpose. Appendicitis can occur at any age but tends to be more common between the ages of 10 and 30.
What are the symptoms of appendicitis?
The major symptoms of appendicitis include:
- Pain that usually begins around your belly button and then moves lower right abdomen
- Loss of appetite
- Nausea and vomiting soon after abdominal pain starts
- Abdominal swelling
- Fever of 99.9°F to 102°F (37.8°C to 38.9°C)
- Inability to pass gas
- Feeling of fullness in your abdomen
As the inflammation worsens, appendicitis pain typically increases and spreads to your right lower abdomen. For some people, pain begins in the lower abdomen rather than around the navel. Anyone with these symptoms should see a doctor or go to the emergency room right away.
What are the causes and risk factors of appendicitis?
The exact cause of appendicitis isn’t clear. Appendicitis is thought to occur when the appendix becomes blocked, often by stool, a foreign body, infection, or cancer. The blockage leads to increased pressure, problems with blood flow, and inflammation. Appendicitis may also occur if the wall of the appendix is damaged by infection or other injury or disease.
Factors that may increase your risk of appendicitis include:
- Blocked or impacted stool in the appendix
- Enlarged lymphatic tissue in the appendix
- Parasitic infections
- Trauma to the abdomen
- Family history of appendicitis
- Age: People between the ages of 10 and 30
- Sex: Males have a slightly higher risk
- Abdominal infections
At what age do people usually get appendicitis?
Appendicitis is most common in people between the ages of 10 and 30, with the peak incidence occurring in the early teens and late teens through the 20s. According to studies:
- Approximately 80% of people with appendicitis are younger than 30 years old
- The peak incidence occurs between ages 10 and 19
- The median age of diagnosis is 28 years old
- Incidence rates begin to decline after age 30
- Appendicitis is rare in children younger than 5 years old
- Rates increase through childhood and peak in the late teens/early 20s
- Incidence declines in the 30s and 40s
- Appendicitis is uncommon after age 50
While appendicitis can happen at any age, it primarily affects adolescents, teens, and young adults in their 20s. Although less common overall, appendicitis rates are also higher in males than females for all age groups.
Appendicitis Incidence by Age Group
| Age Group | Incidence Rate (per 100,000 people) |
|---|---|
| 0-4 years old | 23.0 |
| 5-9 years old | 62.6 |
| 10-14 years old | 104.9 |
| 15-19 years old | 169.6 |
| 20-24 years old | 199.9 |
| 25-29 years old | 164.2 |
| 30-34 years old | 110.8 |
| 35-39 years old | 75.0 |
| 40-44 years old | 46.5 |
| 45-49 years old | 30.6 |
| 50-54 years old | 25.0 |
| 55-59 years old | 23.5 |
| 60-64 years old | 26.1 |
| 65-69 years old | 27.7 |
| 70-74 years old | 27.6 |
As seen in the table, incidence rates for appendicitis begin low in early childhood, rapidly increase through the 10-14 and 15-19 age groups, peak in the early 20s, and steadily decline after age 30. Rates are lowest in seniors over age 70.
Does appendicitis occur more frequently in males or females?
Appendicitis is more common in males than females across all age groups. According to research:
- The lifetime risk of appendicitis is 8.6% for males and 6.7% for females
- The male to female ratio is approximately 3:2
- In children younger than 10 years old, the male to female ratio is close to 1:1
- During the teen years, the male to female ratio increases to 1.4:1
- In young adults, the ratio is 1.5-1.9 males for every female
- After age 50, differences between sexes decrease
The reason males have a higher rate of appendicitis compared to females is not fully understood. Differences in diet, activity levels, or anatomical factors may play a role. The hormonal differences between males and females, especially at younger ages, may also contribute to the higher risk seen in males.
Appendicitis Incidence Rates by Sex
| Age Group | Males (per 100,000) | Females (per 100,000) |
|---|---|---|
| Under 5 years | 27.5 | 18.9 |
| 5-9 years | 75.3 | 50.6 |
| 10-14 years | 124.2 | 86.1 |
| 15-19 years | 200.9 | 140.1 |
| 20-24 years | 240.6 | 161.7 |
| 25-29 years | 191.5 | 139.2 |
| 30-34 years | 128.7 | 94.6 |
This table highlights the higher rates of appendicitis in males compared to females across childhood, adolescence, and young adulthood. The difference is smallest in early childhood and increases through the teen years, peaking in early adulthood.
How does the incidence of appendicitis vary by race and ethnicity?
Some research indicates appendicitis rates may vary between racial and ethnic groups. However, results have been mixed.
According to a 2016 study of U.S. hospitalization rates:
- Non-Hispanic Black patients had the highest rate of appendicitis (11.3 per 10,000)
- Non-Hispanic White patients had an intermediate rate (9.1 per 10,000)
- Hispanic patients had the lowest rate (7.0 per 10,000)
However, other studies have found:
- Appendicitis rates were similar between White, Black, and Hispanic patients
- Pacific Islander and Asian patients had lower rates compared to Whites
- Native American patients had higher rates than Whites
Overall, the research is mixed and more studies are needed looking at potential racial, ethnic, and cultural differences in appendicitis rates. Factors like diet, access to medical care, and anatomical differences may contribute to variances seen between groups. But currently, no consistent significant differences have been found across multiple studies.
How has the incidence of appendicitis changed over time?
The incidence of appendicitis increased steadily from the late 1800s through the mid-1900s. But since around the 1950s, the rate has been declining in the United States and other developed countries.
- From the late 1880s to the mid-1900s, appendicitis rates rose over 200%
- Experts are unsure why rates increased so sharply during this time period
- After peaking in the 1940s-1950s, the incidence of appendicitis began to decline
- From 1970 to 1984, rates decreased by around 37%
- From 1980 to 1997, rates declined by 25%
- Rates continued falling approximately 1-2% per year from the 1990s to 2010s
Some reasons for the declining rates over the past 50-60 years may include:
- Improved sanitation and hygiene reducing infections that can lead to appendicitis
- Changes in diet, such as increased fiber consumption
- Less obstruction and blockages due to intestinal parasites
- Possibly the use of antibiotics treating early appendicitis infections before progression
While appendicitis is becoming less common over time, it remains a fairly frequent condition, especially in adolescents and young adults. But due to declining rates, appendicitis is now less common in the 21st century compared to previous decades.
Conclusion
Appendicitis is most common between the ages of 10 and 30, with peak incidence rates occurring in the late teen years through the 20s. Incidence is lowest at the extremes of age, in early childhood and in seniors over 70 years old. Males have a slightly higher lifetime risk of appendicitis compared to females, especially during the teen and young adult years, although the exact reasons are unclear.
Some studies indicate potential differences in appendicitis rates between racial and ethnic groups, but results have been mixed. After rising over 200% from the late 1800s to mid-1900s, the incidence of appendicitis has declined steadily over the past 50-60 years, likely due to improved hygiene, diet, and other factors. But appendicitis remains fairly common in adolescents and young adults in the 21st century.
