NEW ORLEANS - Latex allergy is a growing concern for many people, especially health care workers (HCWs) and high-risk children, such as those with spina bifida.
"Latex allergy has been called the next major health concern of the decade," Erin Warshaw, MD, said here at the 57th Annual Meeting of the American Academy of Dermatology. Warshaw is chief of dermatology at the Minneapolis Veteran's Administration Hospital and assistant professor at the University of Minnesota.
Most physicians are aware of reactions to latex examination gloves, but don't think about other latex items that may trigger a reaction, such as electrode pads, ventilator tubing and bellows, stethoscope tubing, carpet backing, rubber bands and erasers, etc.
There are two types of products: natural latex products, made by dipping formers in a liquid emulsion of latex, and dry rubber latex, made by molding pressed, dried sheets of rubber. Natural latex products, such as gloves, condoms and balloons, contain the highest amount of antigens, causing the most severe reactions. Dry rubber latex, such as pacifiers, bottle stoppers and tires, usually only cause problems in highly sensitive individuals.
To make gloves, condoms, etc. glass or porcelain formers are dipped into latex emulsion and then dipped in leaching baths. The longer products are in the leaching baths the more latex proteins, which trigger the reactions, are removed. Cheaper gloves have spent less time in the leaching baths, and have a high allergy content.
Allergic individuals have more problems with powdered gloves than non-powdered because cornstarch absorbs the natural latex proteins and aerosolizes them. "This is important especially if you have a patient with prominent respiratory symptoms. They not only have to avoid latex next to their skin, but co-workers may need to change to non-powder gloves," she said.
Endotoxin, which is produced by gram-negative bacteria, can contribute to a reaction. "It has been documented to be a significant contaminant of these cornstarch slurries into which the gloves have been dipped," she explained.
Sensitized patients have specific natural rubber IgE receptors on the surface of mast cells. When these are cross-linked by the latex proteins, they produce a cascade of events in the mast cell that results in degranulation.
Route of exposure may be important, spina bifida patients are primarily exposed during surgery or catheterization, so their mucosa are exposed, where as HCWs are exposed through the cutaneous route by wearing gloves.
Cutaneous exposure, such as when wearing gloves, usually results in urticaria, dermatitis and pruritus. Airborne exposure can result in rhinitis, conjunctivitis and asthma. Mucosal exposure, which occurs during surgery, can result in systemic reactions like anaphylaxis.
Physicians tend to think about the cutaneous manifestations, but when evaluating a patient for latex sensitivities, ask about airway mucosal and systemic reactions, Warshaw recommended.
Reactivity cannot be measured in all individuals, she added. Many patients do not realize they are at risk.
Less than 1% of the general population is sensitized to latex. Prevalence is higher among blood donors, and that may be because health care workers tend to donate more blood.
Those who are at risk include anyone who has had multiple surgical procedures; those with spina bifida; and children born with congenital urologic abnormalities. Thirty percent to 60% of patients with spina bifida are at risk. "Any child who is exposed to multiple surgeries is at increased risk, but spina bifida patients are more likely to be allergic," Warshaw said. The reasons for this are unclear.
Anyone who is occupationally exposed is also at risk for developing sensitivities. The biggest group is HCWs (6%-21%), but also glove manufacturers, hairdressers and food handlers. "Anyone who wears latex gloves on a regular basis," she said.
Eight Steps to Reducing Risk in the Office
About 50% of latex allergy patients are atopic. Anyone who is atopic with preexisting hand eczema is at higher risk for developing sensitivities. Tiny breaks of the skin in eczema may increase the absorption of latex proteins, increasing the risk of sensitization. "Having multiple risk factors act synergistically. If you have a health care worker who is exposed and is also atopic, they are going to be at much higher risk for latex allergy then for these risks added," she explained.
Many fruits and foods have been associated with latex allergy. These include avocado, banana, kiwi, chestnuts, mangoes and passion fruit. Probably this relationship is a cross-reaction between plant proteins. More research is needed so physicians can advise patients about whether or not they need to avoid these foods.
On clinical exam, urticaria wheal is the most sensitive finding. Bright red erythema in the glove area could indicate an allergy. "Unfortunately, most people who come for evaluation have minimum skin findings," she said.
There are three clinical tests for diagnosing latex allergy. The RAST, skin prick and use test. The RAST test is an approved test, has no risk of anaphylaxis and is easy to do - just send the patient to the lab. However, it is insensitive and non-specific; a positive result is helpful, a negative does not rule out latex allergy. The test is also operator dependent, Warshaw said, so you want to use a lab that performs a lot of these.
There is no standardized, approved solution for skin prick tests, although there are "recipes" for making them, which involve placing latex gloves in saline and diluting the mixture. There have been reports of practitioners who did not dilute the solution sufficiently, and the patient had bad outcomes, she warned. It might be a good idea to refer testing to a specialist, who will have epinephrine and a crash cart ready.
The use test works the way it sounds. Patients wear a piece of latex, such as the fingertip of a glove to test for a reaction. The amount of latex and the time of exposure are incrementally increased during the test. The use test is sensitive and specific but can also cause anaphylaxis. It is not standardized, and no glove is approved for this use.
Corticosteroids and antihistamines can help during an acute phase. Don't use barrier creams when wearing gloves, they can make the symptoms worse, Warshaw said.
Patients should carry an EpiPen (epinephrine auto injectable device, Dey Laboratories) and a medical alert bracelet identifying that they have a latex allergy.
Most important, patients with latex allergy must avoid latex. "Obviously, that is easier said then done," she said.
At home, they need to find substitutes for home products, including condoms and diaphragms, if they are sexually active. Natural skin condoms do not protect against HIV, but polyurethane condoms are available in the United States.
Many non-latex gloves are available, but there are concerns about the barrier protections of vinyl because vinyl gloves may tear over an extended period or if the individual does repetitive motions, such as twisting caps on and off when handling IV tubing. These tiny breaks permit transmission of infectious materials, such as HIV.
"I hear health care workers say all the time, `Oh, but I use hypoallergenic gloves," she said. "Everyone grasps onto this term. It is misleading." Products were labeled hypoallergenic if they passed a test that looked for type 4 allergy; most reactions to latex are type 1. "As long as they have a low accelerator content, they can call the glove hypoallergenic, but it is still made of latex." Eight Steps to Reducing Risk in the Office
Because of this misperception, the Food and Drug Administration (FDA) has banned the use of "hypoallergenic" on medical latex products as of September 1998. The FDA also requires a new caution label on all medical latex-containing products. It will take years for hospitals and warehouses to use current stocks, however, so tell patients that hypoallergenic products are not okay and that some medical latex products will not be labeled immediately.
"Latex safe" means that in direct contact with latex-allergic patients, non-latex gloves and products are used. If latex gloves are used elsewhere in the facility, they must be powder free and have a low allergen content. Any dry, molded rubber products, such as stethoscope tubing and wheelchair tires, that come into direct contact with the patient should be covered. Latex-safe operating room (OR) and crash carts are available. Most U.S. children's hospitals have latex-safe ORs for those with spina bifida or congenital abnormalities that require multiple corrective procedures.
In addition, a latex-safe diet is served, which means cross-reactive foods are not served, and food preparers do not wear latex gloves.
Physicians can take steps in the office to reduce the risk for staff and patients. Putting information in the waiting room to inform patients about latex allergy. Many people don't associate their symptoms with rubber products, she said.
Tell staff that latex balloons in the office are not a good idea if someone has a birthday or celebration; Mylar balloons are fine. Also, consider the following: use non-latex gloves; switch to non-latex vial stoppers and syringes, and; switch to plastic adhesive strips.
Think of using non-latex office supplies if you have a lot of high-risk patients, pediatrics, health care workers, etc. Two that are most important - rubber bands and rubber erasers - because the latex can be aerosolized.
For more information:
- Warshaw E. Latex allergy: evaluation and management. Session FOC 815. Presented at the 57th Annual Meeting of the American Academy of Dermatology. March 19-24. New Orleans.
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Copyright 2000, SLACK Incorporated. Revised 15 September 2000.