Dietary recommendations for patients allergic to Anisakis simplex

Area of Science:

• Clinical immunology and allergy
• Foodborne parasitic infections
• Gastroenterology

Background:

• Anisakis simplex is a fish parasite causing IgE-mediated allergic reactions, including urticaria, angioedema, and anaphylaxis.
• Dietary recommendations for patients allergic to Anisakis simplex lack consensus.
• This study evaluates dietary strategies for preventing recurrent allergic reactions to Anisakis simplex.

Purpose of the Study:

• To assess the efficacy of different diets in preventing allergic reactions in patients with Anisakis simplex allergy.
• To compare relapse rates and immunological markers across various dietary interventions.

Main Methods:

• Twenty-eight adult patients with a history of Anisakis simplex allergy were assigned to three diets: fish-free, frozen fish (≥48 hours at -20°C), or fresh fish.
• Raw fish consumption was excluded for all participants.
• Follow-up included monitoring relapse rates and changes in total serum IgE and Anisakis simplex-specific IgE over a mean of 13.16 months.

Main Results:

• No anaphylaxis occurred during the follow-up period across all diet groups.
• Urticaria recurrence was lowest in the fish-free diet group (5.8%), followed by the frozen fish group (11.1%), and highest in the fresh fish group (33.3%).
• Significant decreases in total and specific IgE were observed in all groups, with no statistically significant differences between them.

Conclusions:

• Consumption of fish frozen at -20°C for at least 48 hours is safe for patients allergic to Anisakis simplex, posing no risk of severe allergic reactions.
• Long-term decreases in IgE levels may not reliably indicate avoidance of Anisakis simplex exposure.
• A fish-free diet or a diet including properly frozen fish can effectively manage Anisakis simplex allergy.