What are the common symptoms of anisakiasis?

Most Common Symptoms of Anisakiasis

The most common symptoms of anisakiasis are acute severe abdominal pain, nausea, and vomiting, which typically occur within hours after consuming raw or undercooked fish. 1

Primary Clinical Manifestations

• Gastrointestinal symptoms:

  • Acute severe abdominal pain (predominant symptom) 1
  • Nausea and vomiting 1
  • Diarrhea (less common) 2

• Allergic reactions:

  • Anaphylaxis (can be severe) 1
  • Urticaria and angioedema 3
  • Erythema 3
  • Bronchospasm 3

Clinical Forms of Anisakiasis

1. Gastric Anisakiasis

• Most frequent clinical presentation 3
• Characterized by severe epigastric pain 3, 4
• Pain onset typically occurs within 1-12 hours after consuming infected fish 3
• Can present with chest discomfort in some cases 4

2. Intestinal Anisakiasis

• Presents as acute abdomen 5
• Often misdiagnosed as appendicitis, stomach ulcers, or ileitis 2
• May require surgical intervention if larvae penetrate through the intestinal wall 2

3. Gastroallergic Anisakiasis

• Hypersensitivity symptoms predominate 3
• Time interval between fish consumption and symptom onset can be up to 26 hours 3
• Combination of allergic and gastrointestinal symptoms 3, 4

Important Clinical Considerations

• Symptoms can be influenced by patient factors:

  • Older patients and males are less likely to develop acute abdominal symptoms 6
  • Patients with gastric mucosal atrophy often have milder or absent symptoms 6
  • Helicobacter pylori-naïve patients tend to have more severe symptoms 6

• Laboratory findings may include:

  • Elevated white blood cell count (more common in symptomatic cases) 6
  • Eosinophilia may be present, though not consistently 6

Common Diagnostic Pitfalls

• Anisakiasis is frequently misdiagnosed due to its nonspecific symptoms 2
• Many cases are only diagnosed during surgery for suspected acute abdomen 5
• The sometimes long interval between fish consumption and symptom onset can make diagnosis challenging 3
• Endoscopic examination is the most reliable diagnostic method, allowing direct visualization and removal of larvae 2