Fish allergy tolerance 16 months after diagnosis.

Fish allergy is generally thought to be persistent, and approximately 80% of patients with fish allergies do not develop tolerance even 10 years after diagnosis. There have been no reports of rapid tolerance development in patients with severe fish allergies. We report the development of tolerance 16 months after the diagnosis of fish allergies. A 13-month-old boy was diagnosed with rosefish allergy () and Japanese jack mackerel allergy (). To find out which species of fish he could consume safely, he underwent several oral food challenge (OFC) tests. It was determined that he could consume tuna, salmon, cod, sardine, chub mackerel (), and Japanese amberjack () without eliciting signs of allergy. He continued to eat the fish that did not produce allergic reactions three to four times a week. The titer of serum allergen-specific immunoglobulin E (IgE) to fish had decreased in a subsequent ImmunoCAP-specific IgE blood test performed 16 months after the diagnosis of the rosefish allergy. Following this test result, he underwent OFCs with rosefish and Japanese jack mackerel, both of which turned out to be negative, and it was determined that he had developed tolerance to fish. In this case, the repeated OFCs were useful in identifying fish species that were safe for consumption. In addition, the decrease in allergen-specific IgE was useful in predicting the development of tolerance. We hypothesize that proactive consumption of available fish species may lead to this rapid induction of tolerance to fish allergens.