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Latex allergy is an important medical problem for an increasing number of patients. It results when susceptible individuals are exposed to latex rubber proteins. Natural rubber is derived from the sap or latex of the Hevea brasiliensis tree.
The incidence of allergy to latex varies widely, depending on the population being considered. Data on the frequency of latex sensitization in the general population are limited, but it is estimated to be about 3%. Those at risk for latex allergy include patients who have spina bifida.
Latex gloves, adhesive tapes, urinary catheters, dental devices such as bite blocks, endotracheal tubing, tourniquets, face masks, and straps are some of the medical products containing latex. Household items include balloons, condoms, dishwashing gloves, hot water bottles, swim caps, rubber plants, and toys.
The types of adverse reactions to latex can be categorized into three distinct patterns: irritant dermatitis; delayed, cell-mediated contact dermatitis; and immediate type I immunoglobulin E (IgE)-mediated allergic reaction.
The most common adverse reaction is irritant dermatitis, caused by occlusion of the skin under the impermeable latex barrier. The second most common reaction to latex is delayed, cell-mediated or type IV contact dermatitis. This delayed hypersensitivity reaction is to low-molecular weight accelerators and antioxidants contained in the rubber product. The dermatitis appears 1 or 2 days after contact.
Contact urticaria is the most common manifestation of immediate type I IgE-mediated allergic reaction. Other examples include allergic rhinitis, asthma, and anaphylaxis. Reactions can follow direct contact, such as through the airborne latex allergens attached to glove powder.
Contact dermatitis is not always a clear entity in patients who are allergic to latex. They also may develop an eczematous eruption that is atopic dermatitis. Thus, there may be a subacute dermatitis in chronic glove-wearers that has features of both atopic and contact dermatitis.
When latex allergy is suspected, it is important to obtain any history of symptoms following the blowing up of balloons; during dental or medical examinations (especially pelvic and rectal examinations); immediate redness, itching, or hives from rubber gloves; and unexplained hypotension during surgery.
Diagnosis of the IgE-mediated allergy to natural rubber latex depends on demonstration of latex-specific IgE antibodies. Skin testing with latex is the most sensitive, but at present, there are no licensed commercial extracts available in the United States. Measurement of latex-specific IgE antibodies is not as sensitive as skin testing, but this test is available through diagnostic reference laboratories. This serologic test only detects 50% to 70%.
An association between latex allergy and allergy to banana, avocado, and kiwi fruit has been reported. Apricot, chestnut, grape, passion fruit, and pineapple have been implicated less frequently. Latex-sensitive persons should be questioned about reactions to these foods.
Avoiding latex is the best management. Allergen immunotherapy has not been studied in latex allergy. Educating patients and families and providing a list of latex products and latex substitutions is essential. A latex-free operating room should be made available for patients who have latex allergy. Procedures on children who have spina bifida and other high risks always should be carried out in a latex-free environment. Patients who have latex sensitivity should be instructed to obtain Medi-alert bracelets and carry self-injectable epinephrine.