Latex-Fruit Syndrome is a cross-reactivity phenomenon where individuals allergic to latex develop allergic reactions to certain fruits and nuts due to shared proteins. This reaction is mediated by IgE antibodies that recognize structurally similar allergens between natural rubber latex (NRL) and specific plant-based foods.
Mechanism of Latex-Fruit Syndrome
Latex allergy is triggered by proteins found in natural rubber latex, extracted from the rubber tree (Hevea brasiliensis). The most allergenic latex proteins belong to the Hevein-like family (Hev b 6) and Profilins (Hev b 8).
Cross-reactivity occurs because these proteins are conserved in fruits, vegetables, and tree nuts, leading to immune system confusion (IgE cross-binding).
Key Latex Allergens & Their Cross-Reactive Counterparts
| Latex Allergen | Protein Family | Cross-Reactive Food Allergens | Common Reactions |
| Hev b 1, Hev b 3, Hev b 5, Hev b 6 (Hevein-like proteins) | Chitin-binding proteins | Chestnut (Cas s 3), Banana, Avocado, Kiwi | Severe reactions (Anaphylaxis, Asthma) |
| Hev b 8 (Profilin) | Actin-binding proteins | Hazelnut (Cor a 4), Peanut (Ara h 5), Almond | Mild reactions (Oral Allergy Syndrome – OAS) |
| Hev b 11 (Class I Chitinase) | Chitinase enzymes | Papaya, Chestnut, Tomato | Digestive issues, throat swelling |
| Hev b 12 (Enolase) | Glycolytic enzyme | Coconut, Banana, Latex | Mild respiratory symptoms |
Tree Nuts & Latex Cross-Reactivity
Although tree nuts are not as strongly associated with Latex-Fruit Syndrome as some fruits, certain nuts contain proteins that are structurally similar to latex allergens, particularly Lipid Transfer Proteins (LTPs) and Hevein-like proteins.
| Tree Nut | Cross-Reactive Latex Proteins | Shared Allergen Type | Severity |
| Chestnut (Cas s 3) | Hev b 6 (Hevein-like protein) | Chitin-binding protein | High (Severe Anaphylaxis Risk) |
| Walnut (Jug r 3) | Hev b 12 (Enolase) | Lipid Transfer Protein (LTP) | Moderate |
| Pecan (Car i 3) | Hev b 6-like protein | Lipid Transfer Protein (LTP) | Moderate |
| Hazelnut (Cor a 8) | Hev b 8 (Profilin) | Profilin | Mild (OAS Symptoms) |
Key Tree Nuts at Risk
- Chestnuts have the strongest cross-reactivity due to Hevein-like proteins (Cas s 3).
- Walnuts & Pecans contain LTP proteins (Jug r 3, Car i 3), which are structurally similar to Hev b 6.
- Hazelnuts contain Profilins (Cor a 8), which may trigger mild reactions in latex-allergic individuals.
Symptoms of Latex-Fruit Syndrome
Symptoms range from mild itching to life-threatening anaphylaxis depending on the severity of the reaction.
Mild Reactions (Oral Allergy Syndrome – OAS)
- Itchy mouth, throat irritation.
- Mild swelling of lips, tongue.
- Triggered by hazelnuts, pecans, and walnuts in latex-sensitive individuals.
Moderate Reactions
- Hives, skin rashes.
- Gastrointestinal symptoms (nausea, vomiting, diarrhea).
- Associated with walnuts, pecans, and some fruits (banana, papaya, avocado).
Severe Reactions (Anaphylaxis) Epinephrine (EpiPen®) is the only treatment for anaphylaxis.
- Throat swelling, difficulty breathing.
- Severe drop in blood pressure (anaphylactic shock).
- Most commonly triggered by chestnuts and bananas in latex-allergic individuals.
Who Is at Risk?
- Individuals with Latex Allergy
- Up to 50% of latex-allergic individuals experience cross-reactivity with certain foods.
- Strongest reactions occur with chestnuts, bananas, avocados, and kiwis.
- Healthcare & Latex-Exposed Workers
- Medical professionals, rubber industry workers, hairdressers, and food handlers are at higher risk of latex sensitization.
- People with a History of Multiple Food Allergies
- Those allergic to LTP-containing foods (Rosaceae fruits, tree nuts) may have higher risks of latex-related reactions.
Diagnosis of Latex-Fruit Syndrome
Skin Prick Test (SPT)
- Latex-specific IgE is tested with latex extract.
- Food cross-reactivity is assessed using hazelnut, chestnut, or walnut extracts.
Serum IgE Testing (Component-Resolved Diagnostics)
- Measures specific IgE antibodies to Hev b 6, Hev b 8, Hev b 12.
- Confirms tree nut cross-reactivity risks.
Oral Food Challenge (OFC)
- Gold standard for confirming latex-related food allergies.
- Conducted under medical supervision.
Managing Latex-Fruit Syndrome & Cross-Reactive Tree Nuts
Avoidance Strategies
- Latex-allergic individuals should be cautious with tree nuts (especially chestnuts, pecans, and walnuts).
- Check food labels → Nuts may be present in processed foods, baked goods, or nut-based oils.
- Be aware of hidden latex exposure → Latex gloves, food packaging, and dental supplies.
Emergency Treatment
- Epinephrine (EpiPen®) for severe reactions.
- Antihistamines for mild reactions (itching, OAS symptoms).
- Corticosteroids for prolonged reactions.
Immunotherapy & Emerging Treatments
- Sublingual immunotherapy (SLIT) is being studied for reducing IgE sensitivity to latex and food allergens.
- Potential epitope modification therapies may help desensitize individuals to shared allergens.
Summary of Latex-Tree Nut Cross-Reactivity
| Allergen Source | Key Cross-Reactive Foods | Risk Level |
| Latex (Hev b 6, Hev b 8, Hev b 12) | Chestnut, Walnut, Pecan, Hazelnut, Banana, Avocado, Kiwi | High |
| Chestnut (Cas s 3 – LTP, Hevein-like) | Latex, Peanuts, Bananas | Very High |
| Walnut (Jug r 3 – LTP) | Rosaceae Fruits, Latex | Moderate-High |
| Pecan (Car i 3 – LTP) | Latex, Walnuts, Peaches | Moderate |
| Hazelnut (Cor a 8 – Profilin) | Latex, Grass Pollen | Mild |