3 | PATIENTS AND METHODS
Nineteen Italian allergy centers took part in a multicenter
cross-sectional observational clinical survey on crustacean allergy. In
every participating center, doctors consecutively enrolled the largest
possible number of patients with unequivocal crustacean (shrimp) and/or
mollusks (Bivalvia and/ or Cephalopoda ) allergy, between
May 15th and November 15th, 2021. The patients with a history of food
allergy to shellfish confirmed by a positive skin prick test (SPT) with
commercial shrimp extract and/or with prick-prick test (PPT) with fresh
raw or cooked food were carefully interviewed about seafood, crustaceans
and/or mollusks tolerance. Diagnosis of tolerance was based on patient’s
clinical history (i.e., consumption of the culprit food without
problems).
Shellfish-induced allergic reactions reported by patients included both
mild (such as oral allergy syndrome or isolated gastrointestinal
reactions) and moderate-severe reactions (i.e., urticaria/angioedema,
anaphylaxis). Given the observational nature of the study, no
randomization procedure was be implemented during enrollment. The
clinical histories were confirmed by a positive skin prick test (SPT)
with fresh food (either raw or cooked) and/or commercial extracts of
shrimp and mollusks currently available in Italy (Alk-Abello’ s.p.a.,
Allergy Therapeutics Italia, Anallergo, Firma Srl, Roxall Italia,
Lofarma, and Stallergenes Italia Srl) and/or by the detection of IgE
specific for seafood extracts by ImmunoCAP (shrimp, mussel, clam,
octopus or squid), and Pen a 1 (tropomyosin) (Thermo Fisher, Uppsala,
Sweden). In a subset (98 individuals) a more in-depth evaluation was
carried out by the Allergy Explorer-ALEX2® (Macroarray Diagnostics,
Vienna) multiplex platform evaluating a broader profile of seafood
molecules (9), including Pen m 1 (tropomyosin), Pen m 2 (arginine
kinase), Pen m 3 (myosin light chain), and Pen m 4 (sarcoplasmic calcium
binding protein) all from Black-Tiger shrimp (Penaeus monodon ),
Cra c 6 (the troponin-c from brown shrimp, Crangon crangon ), Der
p 10 (tropomyosin), and Der p 11 (paramyosin) both fromDermatophagoides pteronyssinus , as well as of seafood extracts,
including crab, lobster, northern shrimp, white shrimp, squid, mussel,
oyster, clam, and scallop. IgE levels >0.3kUA/L were
considered positive as for manufacturer’s instructions.
The diagnosis of seafood allergy was not confirmed by blinded or open
oral food challenges due both to the severity of several reactions and
the fact that many centers were not sufficiently equipped in terms of
facilities or personnel to manage possible severe allergic reactions.