A case of a one-year-old girl with cashew nut allergy diagnosed as pectin allergy based on anaphylaxis after ingestion of fruit gummies

Abstract

Pectin is a common food ingredient. Cross-sensitization between cashew and pectin has been reported but not well recognized.

A one-year and 10-month-old girl was referred to our hospital because of anaphylaxis of unknown cause. She had been diagnosed with cashew and walnut allergy at the age of one year and 3 months based on acute urticaria after ingestion of a mixed nuts snack and positive specific IgE to the nuts. Six months later, she was rushed to the emergency room because of generalized urticaria and lethargy after ingestion of fruit gummies not containing nuts. The food components of the gummies were found to be pectin, starch syrup, sugar, and several fruit extracts, which had been eaten without symptoms except for pectin. We suspected pectin allergy and performed a prick-to-prick test and basophil activation tests using individual allergen extracts contained in the snack. Both tests revealed positive reactivities to pectin, not to the other allergens tested, and a diagnosis of pectin allergy was made.

In some cashew nuts allergic patients, a complication of pectin allergy has been reported. Since the prevalence of cashew nut allergy has been increasing in recent years and pectin allergy should be suspected when unexplained anaphylaxis develops in a cashew nut-allergic patient.