What are the common allergens found in cashews?

1. What the science names as “the” cashew allergens

Researchers and clinical resources consistently identify Ana o 1, Ana o 2 and Ana o 3 as the principal molecular allergens in cashew kernels; these named proteins are the targets of IgE antibodies in sensitised patients and are highlighted as the major food allergens in cashew nuts ^{[1] [2]}. Immunology reviews and allergen encyclopedias list these same components when describing which cashew proteins are clinically relevant for testing and research ^{[2] [1]}.

2. Protein families that explain severity and cross‑reactivity

The cashew allergenic proteins map to common seed storage families — 13S globulins (legumin group) and 2S albumins — categories known to provoke severe systemic reactions in susceptible people; clinical sources say these proteins are responsible for severe allergic responses to cashews ^{[3] [2]}. Because these protein families are structurally similar across many plant seeds and tree nuts, they underlie the frequent co‑sensitisation and clinical cross‑reactivity seen between cashew and other tree nuts ^[4].

3. Cross‑reactivity: pistachio, pink peppercorn, mango and other Anacardiaceae

Multiple studies report high cross‑reactivity between cashew and botanically related species. Pistachio is repeatedly named as highly cross‑reactive with cashew, and in vitro work shows IgE cross‑sensitisation to other Anacardiaceae species such as pink peppercorn and sumac; clinical reports also list mango and related foods as potential cross‑reactive items ^{[4] [5] [6]}. Some patient groups are mono‑sensitised, but others show co‑sensitisation patterns that can include both closely related (Anacardiaceae) species and more distant tree nuts ^{[4] [5]}.

4. Clinical picture tied to these allergens

Clinical guidance and reviews emphasise that cashew allergy tends to be potent and persistent, with possible severe systemic reactions including anaphylaxis; the protein allergens described above are implicated in these clinical outcomes ^{[7] [2]}. Symptoms can arise rapidly after exposure and may occur via ingestion, skin contact, or inhalation of dust — underscoring that the implicated cashew proteins can provoke reactions without eating whole nuts ^{[8] [2]}.

5. Diagnostic and practical implications

Because Ana o 1–3 are primary targets of patient IgE, blood tests and component‑resolved diagnostics that measure IgE to these proteins (for example Ana o 3) are used to predict cashew sensitisation, though they don’t necessarily predict reaction severity ^{[6] [1]}. Clinical practice therefore combines history, skin tests, specific IgE measurements, and — where appropriate and safe — supervised oral food challenges to establish true allergy ^{[9] [6]}.

6. Labeling, avoidance and hidden exposures

Public‑facing allergy organizations and food‑safety resources stress that cashew proteins can be “hidden” in processed foods (butters, oils, milks, spices) and that strict avoidance is the main current management strategy since there is no cure ^{[10] [9]}. Regulatory and guidance documents list cashew among the major tree‑nut allergens that must be considered on ingredient labels in many jurisdictions, reflecting the clinical significance of these protein allergens ^{[11] [12]}.

7. Areas of ongoing research and uncertainty

Researchers continue to characterise additional cashew allergenic components and patterns of cross‑reactivity; some studies identify putative novel allergens in cashew, pistachio and pink peppercorn that may explain variable patient responses ^{[4] [5]}. Available sources do not mention whether every cashew processing method (e.g., roasting vs raw) consistently increases or decreases IgE reactivity for each Ana o protein — different studies give conflicting findings about processing effects ^[13].

Limitations and caveats: this summary uses only the supplied sources; specific prevalence numbers, individual risk prediction, and therapeutic choices (for example experimental immunotherapy) require consultation of up‑to‑date clinical guidelines and a treating allergist, and available sources do not fully settle how processing alters each cashew allergen’s potency ^{[13] [2]}.