Abstract
Background: Fish is a leading trigger of food anaphylaxis.
Co-sensitisation to various bony fish species is common due to similar
beta-parvalbumin allergens, leading many fish-allergic individuals
avoiding all types of fish. Cartilaginous fish, like sharks and rays,
predominantly contain alpha-parvalbumin as the major allergen. This
unique allergen profile suggests that cartilaginous fish could be a safe
alternative for bony fish allergic individuals. We aimed to determine
the rate of oral tolerance to gummy shark ( Mustelus antarcticus)
among children with IgE-mediated bony fish allergy and evaluate the
predictive value of raw gummy shark skin prick testing (SPT). Methods:
Children aged 1-18 years with an IgE-mediated bony fish allergic
reaction within the past 3 years underwent medical evaluation and SPTs
to cartilaginous and bony fish species. All participants underwent an
open challenge with 100g cooked gummy shark. Follow-up at 2 weeks and 6
months assessed ongoing tolerance and dietary incorporation. Results:
All 21 children with bony fish allergy tolerated gummy shark during the
challenge, despite seven (33%) children having a positive SPT
(>3mm) to gummy shark (median 5mm). Six months
post-challenge, 7 out of the 21 children (33%) did not incorporate
gummy shark in their diet, citing taste aversion and difficulties
finding a reliable source. There was one reported reaction in the
community to gummy shark following the OFC. Conclusion: Bony-fish
allergic children demonstrated tolerance to gummy shark. SPT to gummy
shark showed limited predictive value in this cohort. Gummy shark may be
a safe alternative in children with bony fish allergy.