Usefulness of the Nasal Allergen Provocation Test in the Diagnosis of Shellfish Allergy
Gelis S1,2, Rueda M3, Pascal M2,4,5, Fernández-Caldas E6,7, Fernández EA6, Araujo-Sánchez G1, Bartra J1,5, Valero A1
1Department of Pneumology and Allergy, Hospital Clínic, Barcelona, Spain
2Institut d’Investigacions Biomèdiques Agustí Pi I Sunyer (IDIBAPS), Barcelona, Spain
3Allergology Department, Hospital Quirónsalud, Barcelona, Spain
4Immunology Department, Hospital Clínic, Barcelona, Spain
5RETICS ARADyAL Network, Instituto de Salud Carlos III, Madrid, Spain
6Inmunotek SL, Madrid, Spain
7University of South Florida College of Medicine, Tampa, Florida, USA
J Investig Allergol Clin Immunol 2022; Vol 32(6)
Background: Shellfish allergy is a major cause of food allergy and anaphylaxis worldwide. Several allergenic proteins have been described in the last few years, but the only diagnostic tool that still enables discrimination between allergic and nonallergic sensitized persons is the oral food challenge (OFC).
Objective: The aim of this study was to evaluate the usefulness of the nasal allergen provocation test (NAPT) as a diagnostic tool in shellfish allergy.
Methods: Forty-five patients with confirmed sensitization to shrimp by a positive skin prick test (SPT) result with a commercial shrimp extract were recruited and classified as sensitized-allergic or sensitized-nonallergic based on current tolerance to shrimp intake, the result of an OFC with a freeze-dried cooked shrimp mixture extract, or a recent history of anaphylaxis induced by shrimp ingestion. These patients and 10 controls not sensitized to shrimp underwent NAPT with a freeze-dried cooked shrimp mixture extract. The response was evaluated using acoustic rhinometry and a visual analog scale.
Results: Significant differences (P=.001) were found between the sensitized-allergic group (18/20 positive NAPT, 90%) and both the sensitized-nonallergic group (2/18 positive NAPT, 11.1%) and controls (0/10 positive NAPT). NAPT enables differentiation between allergic and nonallergic persons with a sensitivity of 90%, specificity of 89%, positive predictive value of 90%, and negative predictive value of 89%.
Conclusions: Our results indicate that NAPT makes it possible to differentiate between sensitized symptomatic patients and sensitized tolerant patients and could be a valuable diagnostic tool when assessing shrimp allergy.
Key words: Nasal allergen provocation test, Nasal allergen challenge, Acoustic rhinometry, Oral food challenge, Shellfish allergy, Shrimp allergy