Perioperative Care of Patients with Latex Allergy - Statistical Data Included

AORN Journal, July, 2000 by Blanca Rosa Davis

Latex is a natural elastic product from the milky sap of the rubber tree Hevea brasiliensis. The tree is native to South America but is widely cultivated throughout the tropics. It produces a milky juice, which is the major source of commercial rubber.(1) The trees are tapped for latex by cutting spiral grooves in the bark and inserting a spout with a cup for collection of the latex. Ammonia is added to promote liquefaction and prevent spoilage. By placing the latex into a centrifuge, a concentrated product is obtained. Latex is made heat stable and elastic by vulcanization (ie, heating in the presence of sulfur). Other chemicals (eg, accelerators, antioxidants) are added for strength, stretch, and durability.(2)

LATEX ALLERGY

The proteins present in natural rubber latex products are thought to be the cause of latex sensitivity and allergic reactions. Immediate hypersensitivity was first reported in 1979, with only sporadic cases until 1990. In the late 1980s, there were 450 incidents of anaphylactic reactions from the latex cuff used on barium enema catheters that resulted in 15 deaths. These reactions caused the US Food and Drug Administration (FDA) to issue an Emergency Alert in 1990, which led to a recall of latex-containing barium enema catheters that year.(3)

The allergic response. Latex contains hundreds of proteins, natural rubber products, and enzymes that are involved in the biosynthesis of robber molecules. Protein fractions in latex are responsible for anaphylaxis, a reaction that can lead to death. Allergic reactions involve the immune system. During an allergic reaction, an antigen interacts with antibodies and produces a massive release of histamine at a local or whole body level.(4) In latex reactions, the latex protein is the antigen.

Types of reactions. Types of reactions to latex products includes dermatitis, contact dermatitis, and immediate hypersensitivity resulting in anaphylaxis. Dermatitis is a chemical irritation, however, and is not a true allergic response. For most affected people, the skin is irritated, dry, and crusty, and symptoms resolve when the contact with latex stops.

Contact dermatitis, or delayed hypersensitivity, occurs between six and 48 hours after contact with an allergen. The affected area becomes dry, crusty, and leathery, with eruptions of sores and blisters. Repeated latex exposure causes the dermatitis to extend beyond areas of latex contact. Many people with delayed hypersensitivity have a history of atopy. This is an inherited tendency toward certain allergies, characterized by symptoms such as hay fever, hives, or asthma, which are produced on exposure to an exciting antigen.

The most severe allergic response is immediate hypersensitivity and anaphylactic reaction. This is an allergic response mediated by immunoglobulin E (IgE) for latex antibodies found in the circulation. On the skin, this can present as hives that migrate beyond the point of contact with latex. Systemic allergic symptoms include itching, watery eyes, swelling of the lips or tongue, shortness of breath, wheezing, dizziness, abdominal pain, nausea, tachycardia, hypotension, shock, and, potentially, death.(5)

Latex rubber has been found to contain more than 240 different polypeptides. Nearly 60 of these show reactivity specific with latex IgE. These polypeptides also can be found in various plants and fruits, which is thought to be why latex allergic individuals have cross-sensitivity to some foods. The most common and prevalent of these cross-reactions are to bananas, avocados, kiwis, and chestnuts.(6) Papaya, mango, melon, potato, tomato, carrot, and celery also are documented as having the potential to cause moderate reactions, and passionfruit, apricot, fig, peach, pear, cherry, pineapple, and hazelnut are responsible for low intensity reactions in latex-sensitive individuals.(7)

During a latex-associated anaphylaxis study conducted from October 1988 through September 1992 for the FDA, researchers explored the prevalence of reactions, number of injuries, and deaths that occurred. During this period more than 1,100 cases of latex anaphylaxis were voluntarily reported. The most frequently reported reactions were due to the use of latex examination gloves and barium enema catheters.(8)

Natural rubber is derived from latex and should be distinguished from synthetic rubber, which is derived from petrochemicals. Synthetic rubber does not contain allergy-inciting plant proteins, but it is virtually identical to natural rubber and its physical properties.(9) When managing latex-allergic patients, nonlatex gloves, made of synthetic rubber, must be substituted for latex-containing gloves. There are several gloves available that, according to the manufacturers, do not contain latex. Some of the materials used include neoprene, styrene butadiene, and polyvinylchloride. The FDA imposes the same quality control standards on all gloves, regardless of manufacturing material.(10)

Latex routes of exposure. Latex protein sensitivity is increasing not only among certain high-risk groups, but also within the general population. People especially at risk for developing latex allergy are patients with repeated medical exposure and those who are occupationally exposed.