Cashew nut allergy and cross-reactions to citrus seeds
What it found
A woman with a known nut allergy had a severe reaction after drinking a sports drink that contained citrus pectin.
Tests showed her immune system also reacted to lemon seed and citrus pectin, alongside cashew and pistachio.
What they found
Studies in people
Reaction to sports drink
The woman developed anaphylaxis after drinking a sports drink that contained citrus-derived pectin.
Skin prick test results
Skin prick testing showed reactions to the sports drink (6 mm), lemon seed (14 mm), citrus pectin (6 mm), cashew (16 mm) and pistachio (11 mm).
Blood antibody tests
Serum-specific IgE testing confirmed sensitisation to storage proteins in cashew and other nuts, including Ana o 3, Cor a 9, Cor a 14, Jug r 1 and Ara h 3.
Tolerance and other reactions
The patient tolerated citrus fruits but had experienced lipoedema on contact with sliced lemon seeds and mild reactions to factory-made jam.
Advice given
Avoidance of citrus seed kernels and added pectin was recommended.
What the authors conclude
“This case illustrates a rare but clinically significant cross-allergy between cashew nuts, citrus seeds and citrus-derived pectin contaminated with citrus seed allergens.”
Also in their conclusions
- They say this case shows a rare but clinically significant cross-allergy between cashew nuts, citrus seeds and citrus-derived pectin contaminated with citrus seed allergens.
- They advise that clinicians should be aware of such cross-reactivity when evaluating unexplained severe allergic reactions in patients with cashew nut allergy.
How it was done
Cashew nut allergy is becoming more common worldwide and may cause allergic reactions to seeds from plants related to cashews, including citrus.
Doctors described one woman in her twenties with a known nut allergy who developed anaphylaxis after consuming a sports drink containing citrus-derived pectin. They carried out skin prick tests and blood tests for specific IgE antibodies.
What it can’t tell you
- We summarised it from the abstract only.
- This is a single case report, so it cannot show how often this cross-reaction happens in other people with cashew nut allergy.
- It cannot prove that citrus pectin or citrus seeds caused the reaction in this woman, only that her tests showed immune reactions to them.
The paper
- Title
- Cross-reactivity in cashew nut allergy
- Type
- Case report
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Kahrs GE, Lied GA (2026). Cross-reactivity in cashew nut allergy. Tidsskrift for den Norske laegeforening. doi:10.4045/tidsskr.25.0816PubMed 42622389DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error