Allergies To Rubber Affect 12.5 Percent Of Health Care Workers

Tests show that 2.5 percent of the group are already having allergic reactions to proteins from the gloves, but another 10 percent are "sensitized" to the proteins: they have special antibodies linked to allergies and specific for the rubber proteins, but no allergy symptoms yet.

"They have produced IgE antibodies, and when these antibodies re-encounter rubber proteins under the right circumstances, they can set off a potentially serious allergic reaction," says Robert G. Hamilton, Ph.D., associate professor of medicine, who led what is believed to be the first definitive U.S. prevalence study of allergies to rubber proteins.

Hamilton presents his group's results, funded by the National Institutes of Health, on March 15 at the annual meeting of the American Academy of Allergy, Asthma and Immunology.

Hamilton has been a leader in efforts to reduce hospital use of products containing rubber, sometimes called latex, for health care professionals and patients. He is concerned that the potentially life-threatening consequences of this allergy are still very underappreciated. Reactions can range from a localized skin rash or sneezing to respiratory distress or death.

"These reactions become progressively worse with repeated exposures, so it's important to identify both those who are sensitized and those who already have allergy symptoms," says Hamilton. "By stopping exposure, we should be able to stop the sensitized but asymptomatic group from developing symptoms."

Examination and surgical gloves are believed to be the main risk factors for health care workers, but other stretchable rubber objects, such as balloons or condoms, can cause a reaction. Rubber proteins from the gloves can be absorbed through direct skin contact. They also can attach to corn-starch donning powder inside the gloves and enter the body through inhalation when the gloves are pulled off and the powder becomes airborne.

Hamilton's group studied 168 Hopkins anesthesiologists, first identifying those already allergic with "real life" exposure: wearing a glove and inhaling the powder after removal. Two-and-a-half percent had clinical symptoms.

He also gave subjects a "skin-prick" test with a rubber extract and a blood test to see if IgE antibodies specific for rubber proteins were present.

Twelve-and-a-half percent were positive, meaning that a full 10 percent have become sensitized but are not symptomatic yet.

Performance data for the extract Hamilton used in the skin test, which his team developed, are undergoing review by the Food and Drug Administration. Approval for nationwide distribution is possible within a few months, which would make the extract the basis of the first characterized latex skin test reagent in the United States.

A task force to study use of the gloves and other products containing rubber at Hopkins has led to the use of alternative gloves made from vinyl and nitrile.

Co-authors on the study were Robert Brown, M.D., and James Schauble, M.D.