Healthcare workers are living in an age of universal precautions where the use of latex gloves is ubiquitous as protection against blood-borne infection. With increased use has come a surge in the number of health problems related to contact with latex. Natural latex is found in a wide variety of products. We could make a very long list of items—some found in medical settings: blood pressure cuffs, stethoscopes, tourniquets, rubber gloves; others found in the office: rubber bands, parts of furniture, floor mats; and many found at home: tires, pacifiers, balloons, condoms, shoes, and sports equipment. Natural latex has been around for a long time and we have all had contact with it; but the health problems related to natural latex can be attributed largely to the increased use of natural latex in healthcare settings, suggesting that the primary culprit is rubber gloves.

Natural latex comes from the sap of the rubber tree, Hevea brasilienses. There are products that use the name latex but do not contain natural latex. These products use synthetic polymers that do not have the same properties of sensitization. An example would be "latex" paint, which does not contain natural latex.

Exposures

Exposure to latex can occur by contact or by inhalation of airborne particles. Contact exposure, of course, may result from wearing latex gloves. But if someone wearing latex gloves touches objects such as instruments, phones, or specimen containers, they may leave a trail of residual latex allergens on those objects. When other people subsequently touch these contaminated objects, they may be exposed to the latex allergens, even though they didn’t wear latex gloves themselves. Furthermore, the use of creams or lotions on the hands may enhance the contact with latex allergens.

Airborne exposure to latex allergens is primarily a problem arising from the use of cornstarch as a powdering agent. Latex allergens bind to the cornstarch particles, and there is evidence that the combination of latex allergen and cornstarch is more highly immunogenic than latex alone. Airborne exposure may be respiratory or through contact with mucous membranes. Skin contact from airborne exposure is less significant than respiratory and mucous membrane exposure.

Latex contains both IgE-mediated, Gell and Coombs Type I immediate hypersensitivity allergens, and Gell and Coombs Type IV delayed hypersensitivity allergens. Type IV allergens cause delayed hypersensitivity. In the manufacturing process for natural latex products there are several substances, including natural latex itself, that can cause delayed hypersensitivity. These include thiurams, dithiocarbamates, benzothiazoles and phenylenediamines. Type I allergens are proteins containing natural latex. The amount of these allergens present in latex products is greatly affected by the manufacturing process, and, most importantly, by the use of cornstarch as a lubricant to minimize sticking when pulling gloves on and off.

Cross Reactivity

There is cross reactivity between latex allergens and allergens found in several foods. These foods include avocados, bananas, chestnuts, kiwis, and papayas. This cross reactivity is important to note because it may play an important role in diagnosing latex allergy and will play a role in managing latex allergy.

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A variety of symptom complexes and health problems can arise from contact with natural latex. These health problems range from dermatitis and delayed hypersensitivity reactions, to IgE-mediated hypersensitivity reactions, which can lead to acute responses that include a variety of local and/or systemic reactions. The systemic reactions can include swelling, respiratory compromise, or anaphylaxis.

Symptoms related to latex exposure include: pruritis, urticaria, rhinitis, conjunctivitis, shortness of breath, and anaphylaxis. Latex may also cause occupational asthma. Irritant contact dermatitis and delayed hypersensitivity rashes of the hands injure the skin and render the individual more susceptible to infection. There are three main types of reactions to latex: irritant contact dermatitis, delayed hypersensitivity, and latex allergy.

The most common problem noted with the use of latex gloves is irritant contact dermatitis unassociated with any hypersensitivity. Irritant contact dermatitis is characterized by dry, itching, reddened, irritated areas of the hands. It is induced by contact with the latex or chemicals in the glove, and moisture from sweating may play an important role.

Allergic contact dermatitis (delayed hypersensitivity) is characterized by vesiculation—irritated skin with vesicles and oozing. The rash looks very much like the rash of poison oak or poison ivy. Onset is usually 24–48 hours after contact with the allergen.

Latex allergy (immediate hypersensitivity) reactions usually begin within minutes of exposure, but can occur as late as several hours after contact. There is a broad spectrum of reactions ranging from mild, such as redness or urticaria, to severe: rhinitis, conjunctivitis, shortness of breath, angioedema, and anaphlylaxis. Anaphylaxis is rarely the first manifestation of latex allergy.

Diagnosis

The diagnosis of health problems related to latex exposure involves obtaining relevant medical history in conjunction with diagnostic testing. Pertinent history includes atopy, eczema, hay fever, asthma, urticaria, anaphylaxis, and food allergies, particularly to foods mentioned above. Other pertinent information includes frequent historical contact with latex, which is common for healthcare workers, food handlers, or patients subjected to multiple surgical procedures. Any history of urticaria, rashes, rhinitis, conjunctivitis, or shortness of breath shortly after putting on latex gloves is highly suggestive of latex allergy.

There are latex-specific IgE blood tests available for diagnostic testing. The preferred testing methods, however, are use testing or skin-prick testing. Use testing is accomplished by placing the cut-off finger of a latex glove over a test subject’s moistened finger. The latex is left in place for 15 minutes. If there is no reaction, then the entire hand may be tested using a vinyl glove on the opposite hand as a control. Skin-prick testing is accomplished by scratching or pricking the skin through a drop of liquid containing latex proteins. Standardized extracts are available for skin-prick testing and a positive test is demonstrated by redness, swelling, or itching at the test site. There is also a standardized, FDA-approved patch to test for allergic contact dermatitis due to latex. A positive reaction to this test is manifested by itching, redness, swelling, or vesiculation at the site of the patch.

Exposure Control

A latex exposure control program should be part of standard operating procedures. I recommend as a first step to use powder-free, low-protein gloves, even though they are a bit more expensive. Note that the label "hypoallergenic" does not mean that a particular product is free of latex that might cause sensitization. If the product is made of natural latex, there is still a potential for sensitization. Those with diagnosed Type I latex allergy should not use latex gloves, period. There is no guaranteed safe level of exposure for individuals with diagnosed Type I hypersensitivity.

You should, where possible, use an alternative form of gloves. Any glove that meets the ASTM (American Society for Testing and Materials) standards and FDA requirements is an adequate barrier against such pathogens as HIV and hepatitis B. Vinyl gloves are less durable than latex and it is often recommended that they be changed every 30 minutes. Double gloving with vinyl gloves may be used for surgical and other procedures where latex allergy is a problem for the patient or the staff. Nitrile gloves provide a somewhat better barrier against pathogens than latex, but may also cause hypersensitivity problems. Both Neoprene and thermoplastic elastomer (TPE) gloves perform well and are adequate barriers against pathogens; but the cost of these gloves is somewhat higher.