Sublingual immunotherapy for allergy to shrimp: the nine-year clinical experience of a Midwest Allergy-Immunology practice.

Background: Diet restrictions and fear of adverse reactions put a significant burden on the nutrition, growth and life style of children and adults with food allergies. While various disease-modifying options are pursued, there are so far no published clinical data on immunotherapy for crustaceans. The efficacy and safety of desensitization to crustaceans by means of sublingual immunotherapy is assessed for the first time in this study with a view of validating it as a clinical-practice modality.

Methods: Charts of a Midwest Allergy-Immunology practice from the period January 2014-June 2023 were reviewed to identify patients with allergy to shrimp treated with sublingual immunotherapy and to retrospectively evaluate their responses to oral challenge.

Results: Sixty-six patients were identified who had been treated by sublingual immunotherapy for either systemic or localized reactions to shrimp. Demographics and relevant comorbidities were consistent with those of the atopic population. Sublingual immunotherapy with serially diluted mixtures was initiated at 64-320 ng/dose and was gradually escalated to 0.5 mg/dose three times a day. The sublingual immunotherapy course ranged from 5 to 72 months (average: 51 months), following which, 18 patients underwent shrimp oral challenge. No systemic reactions occurred upon challenge; no patient required epinephrine. Tolerance of target dose equal to or exceeding 42 g shrimp was achieved in 11 patients (61%), seven of whom had originally presented with systemic reactions to crustaceans. Seven patients (38%) developed one or more of the following localized reactions: oral itching, nasal symptoms, localized perioral hives, localized hives at pressure points, nausea, vomiting, abdominal pain upon exposure to a cumulative dose of 39.2-148.2 g of shrimp during the 4 h of the challenge. Five of these patients had originally presented with systemic reactions to crustaceans. Five of the 7 patients who developed localized symptoms during the challenge were subsequently placed on routine exposure to 12-20 g shrimp every other day. Two patients continued sublingual immunotherapy but declined routine exposure to shrimp every other day because they had no intention to incorporate crustaceans to their routine diet. On repeat challenge 6-9 months after original challenge, all five patients who had routine exposure to 12-20 g shrimp every other day tolerated the procedure to target dose without any symptoms.

Conclusions: Desensitization to shrimp by sublingual immunotherapy appears to be safe and effective as shown in this study. Whether the immune modification induced by sublingual immunotherapy is permanent resulting in sustained tolerance, or the achieved degree of desensitization depends on regular exposure is not known; therefore, following challenge, regular consumption three-four times per week was recommended.