Latex Allergy

Urticaria after wearing latex gloves. Source: CDC.

Signs and Symptoms

Example of a skin reaction to latex. Source: Chris Wheatley

Anaphylactic reactions to latex have been reported in persons who had previously only experienced irritant or allergic contact dermatitis. One theory is that underlying dermatitis breaches the skin's protective barrier, facilitating increased latex protein absorption and increasing the likelihood that the person will become sensitized to latex. Contact dermatitis may also be caused by a wide range of chemicals used in glove manufacturing; in particular, the accelerators.

Causes

Direct skin contact with latex may cause a type I, or immediate hypersensitivity, IgE-mediated reaction within 30 to 60 minutes of exposure. Urticaria may be local or generalized, and the spectrum of progression is notably unpredictable--some persons have experienced anaphylactic reactions after having minimal or no previous symptoms. It is possible to have used latex gloves for years and to suddenly have a progression to systemic symptoms.

Certain fruits such as bananas, chestnuts, kiwi fruit, avocado and tomato show cross-reactivity, perhaps because of resemblance to a latex protein component. These foods have been responsible for anaphylactic reactions in latex-sensitive persons, while many other foods, including figs, apples, celery, melons, potatoes, papayas and pitted fruits, such as cherries and peaches, have caused progressive symptoms beginning with oral itching. Persons with a history of reactions to these foods are at increased risk of developing latex allergy, and those who are sensitive to latex should avoid foods to which they have had previous reactions. While food cross-reactions remain an evolving area of knowledge, it is clear that the elimination of all of these foods would cause significant dietary restriction and is therefore not recommended categorically for latex-allergic persons.

Diagnosis

Diagnosis of latex allergy is made by the history and by immunologic testing; a thorough medical history is the cornerstone of diagnosis. The patient should be asked about their occupation, and other factors for high risk should be explored. Also, the history should determine whether previous reactions have occurred in an occupational or other setting and, if so, what type of reactions occurred. Reactivity to foods, symptoms following use of a rubber condom or diaphragm, or symptoms associated with pelvic examination should raise the suspicion of latex sensitivity.

Standardized extracts for skin prick testing are not available in the United States. Therefore, because such testing may cause anaphylaxis, it should only be conducted by centers with experience in preparing extracts. FDA-approved in vitro tests to measure latex-specific IgE are available. The low specificity of these tests, which have a false-negative rate of at least 20 percent and, thus, unclear positive predictive value, limits clinical usefulness. Negative serologic testing with a strongly positive history would suggest the value of skin prick testing to confirm the diagnosis.

Treatment

Acute systemic reactions to latex should be treated in the same manner as any anaphylactic reaction. The airway, breathing and circulation are assessed, oxygen is provided, and epinephrine and steroids are administered. Diphenhydramine (Benadryl) may be used for urticaria. In the course of resuscitation, all latex contact is avoided. Fluids and nebulized medications for bronchospasm may be required. Treatment should be continued with monitoring after symptoms resolve. It is unfortunate that for the exquisitely latex-sensitive person, the hospital and emergency department settings may be the most fraught with danger. Growing awareness of the magnitude of health risk posed by latex allergy may improve this paradoxic situation.

Prevention

Workplace decisions should be made to reduce cumulative exposure to latex, including the widespread purchase of nonpowdered, low-protein latex and nonlatex gloves. New ways of treating latex have resulted in powder-free gloves that are actually easier to don than powdered gloves. Some newer glove products have very low solubilized and aerosol titers of proteins, but wide variation remains between brands. For health care workers and patients who are allergic to latex, nonlatex gloves must be used. The National Institute of Occupational Safety and Health (NIOSH) has just published an advisory document on natural latex rubber in the workplace. It recommends that nonlatex gloves be used for all activities that are not likely to involve contact with infectious materials (e.g., food preparation, routine housekeeping and maintenance).

Persons with latex hypersensitivity should carry an epinephrine auto-injection kit and wear Medic-Alert identification. Carrying extra pairs of nonlatex gloves for emergency medical or dental care is also advisable. The Spina Bifida Association of America produces a list of latex products and latex-free substitutes in both community and hospital settings. This detailed list is helpful in preparing hospital protocols or finding nonlatex replacements for materials.

Chances of Developing Latex Allergy

Natural rubber latex has been in widespread use for over a century. Reports of immediate hypersensitivity to latex have increased dramatically since the first case was reported in 1979. Sixteen deaths occurred in association with the use of a latex barium enema tip, leading to the recall of the device in 1991 by the U.S. Food and Drug Administration (FDA) and an increase in awareness of the risk of a life-threatening type I allergy associated with natural latex devices.^[2] Ten to 17 percent of health care workers have already become sensitized, and over 2 percent have occupational asthma as a result of latex exposure.

Other persons at high risk of sensitization include those with cumulatively prolonged exposure to latex. Among those who have undergone repeated surgeries, particularly early in life--especially those with myelomeningocele (spina bifida) or urogenital abnormalities--the prevalence of latex allergy may be greater than 60 percent. Workers in the latex manufacturing industry are also at risk, with one glove manufacturing plant reporting a 3.7 percent prevalence of occupational asthma caused by latex allergy among its employees, based on positive results of skin prick testing and spirometric data. Among workers at a latex doll manufacturing plant, the prevalence of latex sensitization was also shown to be significant.

High-exposure areas, such as operating rooms and labor and delivery suites where powdered latex gloves are used, contain sufficiently elevated concentrations of aerosolized latex to produce significant symptoms in sensitized persons.

Interesting Facts

Since 1985, the establishment of policies of "universal precautions" and the increased barrier requirements resulting from the epidemic of human immunodeficiency virus infection and acquired immunodeficiency syndrome have resulted in an exponential increase in the use of latex gloves. In 1987, 1 billion latex gloves were imported into the United States; in 1988, 8 billion gloves were imported. The use of latex condoms has also increased. It appears that the increase in total exposure to latex and variations in manufacturing have led to a true increase in the number of persons with latex sensitivity.

Latex products are derived from the latex sap of commercially grown rubber trees, Hevea brasiliensis. The sap is extracted and heated while chemical preservatives, primarily ammonia, are added to enhance the rubber's structural qualities. Latex contains low-molecular-weight soluble proteins, which are the cause of IgE-mediated allergic reactions. At least 10 different proteins have been implicated.^[3] Added accelerators and antioxidants may also be significant mediators of type IV or allergic contact dermatitis, and may cause or exacerbate irritant contact dermatitis.

Latex products are made either by pouring the rubber into molds or by forming a coating in a dipped process, as is done with gloves, balloons and condoms. Dipped, or very soft, rubber products appear to have the highest content of latex proteins and, therefore, have the greatest allergenic potential. Cornstarch powder is applied to latex gloves during the manufacturing process to prevent stickiness and give the gloves a smooth feel. Latex protein particles have been shown to adhere to the surface of these cornstarch particles and to aerosolize on removal of the gloves.

References

1. ↑ Brehler R, Kütting B. Natural rubber latex allergy: a problem of interdisciplinary concern in medicine. Arch Intern Med. 2001 Apr 23;161(8):1057-64. Abstract | Full Text | PDF
2. ↑ Kokoszka J, Nelson R. Latex anaphylaxis. Dis Colon Rectum. 1993 Sep;36(9):868-72. [http:/pubmed.gov/8375231 Abstract]
3. ↑ Yeang HY, Arif SA, Yusof F, Sunderasan E. Allergenic proteins of natural rubber latex. Methods. 2002 May;27(1):32-45. Abstract