Stomach Flu or Appendicitis: How to Tell the Difference

Overview

Abdominal pain, nausea, vomiting, and diarrhea are common symptoms that can signal very different medical conditions. Two possibilities that are often confused—especially early on—are viral gastroenteritis (often called the “stomach flu”) and appendicitis.

While both can cause gastrointestinal discomfort, they differ significantly in cause, risk, and treatment. Importantly, appendicitis is a medical emergency, while viral gastroenteritis most often improves with supportive care. Because early symptoms can overlap, careful medical evaluation is sometimes necessary.

Key Differences

• Appendicitis
• Medical emergency
• Pain typically worsens over time
• Pain often starts near the belly button and later moves toward the right side of the abdomen
• Usually treated with surgery
• Viral Gastroenteritis (Stomach Flu)
• Infection of the digestive tract
• Commonly causes diarrhea and vomiting
• Most cases improve within a few days
• Treated with supportive care

What Is Appendicitis?

Appendicitis is inflammation of the appendix, a small tubular structure connected to the large intestine. The function of the appendix is not fully understood.

Verified medical evidence shows that:

• Appendicitis commonly causes abdominal pain that worsens over time, often over 24–48 hours.
• Pain frequently begins near the belly button and later moves toward the right side of the abdomen.
• Pain often becomes worse with movement, coughing, sneezing, or walking.
• Common associated symptoms include loss of appetite, nausea or vomiting, and low-grade fever.
• Appendicitis is considered a medical emergency because the appendix can rupture, allowing infection to spread within the abdomen.
• Treatment usually involves surgical removal of the appendix, with antibiotics used in some cases depending on severity.

What Is the Stomach Flu (Viral Gastroenteritis)?

Viral gastroenteritis is an infection of the digestive tract.

High-quality evidence shows that:

• Symptoms commonly include diarrhea, vomiting, nausea, abdominal pain, fever, and fatigue.
• Most cases improve within a few days.
• Treatment focuses on supportive care, such as hydration, rest, and symptom management.
• Antibiotics are not effective against viral infections.

How Symptoms May Overlap—and Differ

Pain Pattern

• Appendicitis: Pain typically worsens steadily and does not improve.
• Viral gastroenteritis: Abdominal pain may be crampy and occurs along with prominent diarrhea and vomiting.

Diarrhea

• Diarrhea is common in viral gastroenteritis.
• Diarrhea is less typical in appendicitis, but evidence shows it can occur in some cases and may complicate diagnosis.

Vomiting

• Vomiting can occur in both conditions.
• Appendicitis may sometimes present with vomiting and diarrhea, which is why it can be mistaken for gastroenteritis early on.

Appendicitis in Children vs. Adults

• Appendicitis can be more difficult to diagnose in children, particularly younger children who may struggle to describe symptoms clearly.
• Older children and adults are often better able to describe pain progression.
• Appendicitis can still be mistaken for gastroenteritis in its early stages at any age.
• In all age groups, worsening or persistent abdominal pain warrants medical evaluation.

How Appendicitis Is Diagnosed

Diagnosis may include:

• A physical examination, focusing on abdominal findings
• Blood tests, such as white blood cell count
• Imaging studies, including ultrasound or CT scans

Evidence shows that early diagnosis reduces the risk of complications.

When to See a Doctor

Prompt medical evaluation is recommended if:

• Abdominal pain continues to worsen over time
• Pain becomes more intense with movement
• Appendicitis is suspected based on symptoms

These recommendations reflect evidence that appendicitis requires timely medical care.

Frequently Asked Questions

Key Takeaway

Viral gastroenteritis and appendicitis can cause similar early symptoms, but appendicitis is a medical emergency. Abdominal pain that steadily worsens—especially when aggravated by movement—should not be ignored. When symptoms are unclear, medical evaluation is the safest course.

APA Reference List

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