Latex Fruit Syndrome

Latex fruit syndrome is the association of natural rubber latex allergy with IgE-mediated reactions to certain plant foods, mainly banana, avocado, kiwi and chestnut. It arises from cross-reactive proteins.

Pathophysiology. Latex proteins (Hev b 6.02 hevein, and Hev b 2, Hev b 5, Hev b 7) share epitopes with class I chitinases in banana, avocado, kiwi and chestnut, and with patatin like proteins in potato and tomato. IgE made after latex exposure binds these food proteins.

About 30 to 50% of latex allergic patients have an allergic reaction to one of these foods, and some patients present first with the food allergy.

Latex allergy is commonest in healthcare workers, people with spina bifida or urogenital anomalies, patients with many operations, and rubber industry workers.

• Contact urticaria, itching and swelling after glove or balloon contact
• Rhinitis, conjunctivitis and asthma from airborne latex particles
• Anaphylaxis during surgery or examination with latex devices
• Oral itching, urticaria, angio oedema or anaphylaxis after banana, avocado, kiwi or chestnut
• Reactions to other foods: potato, tomato, bell pepper, papaya, mango, fig, melon
• Delayed hand dermatitis from glove chemicals (a separate type IV allergy)

• History: latex exposure, occupation, previous surgery, and food reactions.
• Specific IgE to latex and to Hev b 5 and Hev b 6.02: Hev b 6.02 positivity points to cross-reactive food disease. Test specific IgE to the suspect foods.
• Skin prick test with latex extract and fresh food (prick-to-prick): latex extract may not be available in all centres.
• Glove provocation test in a controlled setting when results are uncertain.
• Patch testing for rubber accelerators if hand dermatitis is delayed.

Differential diagnosis.

• Irritant contact dermatitis from gloves
• Allergic contact dermatitis from thiurams and carbamates (type IV)
• Pollen food allergy syndrome
• Primary food allergy
• Other perioperative allergens (chlorhexidine, neuromuscular blockers)
• Idiopathic anaphylaxis

• Latex avoidance: use nitrile or other latex free gloves and devices, and a latex safe environment for any procedure. Schedule the patient first on the operating list.
• Food avoidance: avoid foods that have caused reactions. Test and challenge other related foods rather than avoiding all of them.
• Mild reactions: cetirizine 10 mg orally once daily in adults (children 1 to 5 years 2.5 mg twice daily; 6 to 11 years 5 mg twice daily).
• Anaphylaxis: adrenaline 0.5 mg intramuscularly (children 0.01 mg/kg, maximum 0.5 mg) into the anterolateral thigh, repeated after 5 minutes if no improvement, plus oxygen and intravenous fluids, and observation for at least 6 hours.
• Adrenaline auto injector for systemic reactions: 150 microgram for 7.5 to 25 kg, 300 microgram for 25 to 50 kg, 500 microgram for over 50 kg, with a written action plan and training.
• Occupational disease: reduce exposure (powder free, low protein or latex free gloves), reassign if needed, and review for asthma.
• Medical alert: a bracelet or card stating latex allergy, and a note in the hospital record.
• Latex immunotherapy is not routine.

Special groups.

• Children with spina bifida: avoid latex from birth, since sensitisation is frequent.

Monitoring. Review every 12 months. Check auto injector dose and expiry. Spirometry in occupational asthma.

Referral and escalation. Refer to allergy and occupational health for suspected latex allergy. Emergency for anaphylaxis during any procedure.