Latex Allergy

Latex allergy is an immune reaction to proteins in natural rubber latex from the Hevea brasiliensis tree. Two main mechanisms exist: type I immediate hypersensitivity (IgE to latex proteins, called Hev b antigens), which causes urticaria, rhinitis, asthma and anaphylaxis, and type IV delayed hypersensitivity to rubber additives (thiurams, carbamates and mercaptobenzothiazole), which causes allergic contact dermatitis. Irritant dermatitis from gloves is common but not allergic.

Prevalence is 1 to 2% in the general population, 8 to 12% in healthcare workers and 30 to 60% in children with spina bifida or other conditions with repeated surgery and bladder catheterization. Powdered gloves carry latex proteins in aerosol on the cornstarch powder, and the switch to powder-free low-protein gloves has reduced sensitization.

Risk factors: atopy, repeated exposure through mucosal surfaces, multiple operations, rubber industry work and a history of hand eczema. About 30 to 50% of latex-allergic patients react to foods that share epitopes (banana, avocado, kiwi, chestnut, papaya, mango, tomato and potato), called the latex-fruit syndrome. Severe reactions happen during surgery, dental treatment and gynecological examination. Complications: anaphylaxis, occupational asthma, chronic hand dermatitis and career loss.

• Within minutes of contact: itching, redness and wheals at the contact site, rhinoconjunctivitis, wheeze, and sometimes generalized urticaria
• Anaphylaxis: angioedema, stridor, hypotension and collapse, 20 to 60 minutes after mucosal contact or during surgery
• Delayed type: eczematous eruption 12 to 72 hours after glove use
• Oral itching and swelling after eating the cross-reacting fruits
• Red flags: wheeze or collapse after contact with gloves, balloons or catheters, and unexplained anaphylaxis under anesthesia

1. History of reaction timing and the exposures involved.
2. Serum specific IgE to latex (value of 0.35 kU/L or more is positive, sensitivity about 75 to 90%).
3. Skin prick test with a standardized latex extract, performed with resuscitation equipment available (sensitivity over 90%).
4. Basophil activation test or component-resolved diagnosis (Hev b 5, 6.01 and 8) when results conflict.
5. Controlled glove use test or provocation test only in specialist units with emergency support, for uncertain cases.
6. Patch testing to rubber additives for delayed reactions.
7. Tryptase within 1 to 2 hours of a perioperative reaction, with a baseline level later.

Differentials: irritant glove dermatitis, other allergens in gloves, anaphylaxis to anesthetic agents, chlorhexidine allergy and idiopathic urticaria.

1. Avoidance: latex-free gloves (nitrile, neoprene), catheters, tourniquets and equipment. Powder-free low-protein latex gloves for staff in the same area. A latex-safe environment in healthcare settings, with the allergic patient scheduled first on the list.
2. Anaphylaxis: epinephrine 0.5 mg IM (0.5 mL of 1:1000) into the anterolateral thigh (children 0.01 mg/kg, maximum 0.5 mg), repeated every 5 minutes as needed. IV crystalloid 20 mL/kg, oxygen, chlorphenamine 10 mg IV (children 0.2 mg/kg) and hydrocortisone 200 mg IV (children 4 mg/kg), salbutamol 5 mg nebulized for wheeze, and observation for at least 6 hours.
3. Self-treatment: epinephrine auto-injector 0.3 mg IM for patients over 30 kg (0.15 mg for 15 to 30 kg), two devices carried at all times, with training and a written action plan. Medical alert identification.
4. Mild symptoms and rhinitis: cetirizine 10 mg orally once daily, and fluticasone furoate nasal spray 27.5 micrograms, 2 sprays per nostril daily.
5. Allergic contact dermatitis: mometasone furoate 0.1% ointment once daily for 2 weeks and glove substitution (non-thiuram nitrile gloves).
6. Latex-fruit syndrome: avoid or cook cross-reacting foods when they cause symptoms.
7. Premedication does not reliably prevent reactions, and is no substitute for avoidance.
8. Allergen immunotherapy is not used routinely, since severe reactions limit its safety.
9. Occupational disease: notify and arrange work modification, and change to a latex-free role when needed.

Follow-up yearly with repeat specific IgE if clinically needed. Counsel on informing every dentist, surgeon and nurse before any procedure.