There have not been many studies to see whether someone can outgrow seafood allergy unlike peanut allergy where 20% is considered the norm. Can you outgrow peanut allergy?
Seafood allergy includes allergy to either fish or shellfish although the main allergenic proteins differ between these groups. Worldwide prevalence of allergy to fish is reported to be as high as 1.5% for adults and 7% for children, whereas shellfish allergy is reported to affect up to 2% of adults and 5.5% of children.
In the United States, 0.5% of adults and 0.2% of children reported fish allergy and shellfish allergy was reported in 2.5% versus 0.5% respectively. Seafood is therefor a relatively prevalent group of allergens and together with peanut and tree nut accounts for the most severe cases of food-induced anaphylaxis.
A recent study in Canada published in The Journal of Allergy and Clinical Immunology In Practice, studied the rate to outgrow seafood allergy.
Participants were considered allergic to fish/shellfish if they met at least 1 of the following criteria.
- Convincing history and positive skin test result. A convincing history referred to at least 2 mild signs and/or symptoms or 1 moderate or severe sign and/or symptom that was likely IgE-mediated and occurred with 120 minutes of seafood ingestion, skin contact or inhalation. Mild signs/symptoms included itching, hives, flushing, itchy throat or rhinoconjunctivitis; moderate signs/symptoms included swelling, stridor, coughing, abdominal pain, difficulty breathing, voice changes, nausea, vomiting or diarrhea; severe symptoms included wheezing, cyanosis and circulatory collapse
- Specific IgE levels in the blood for fish of at least 20 kU/L
- Positive oral challenge
Participants reported the most common fish and shellfish allergy culprits were salmon (18.4%) and shrimp (50%) respectively.
The resolution rate for fish was only 0.6% and 0.8% for shellfish, per person-year.
Given these results, it is very unlikely a patient will outgrow seafood allergy, whether it be fish or shellfish. Given these low rates, it would not be part of routine clinical practice to challenge these patients especially if their blood allergy IgE is 20kU/L or higher.