Preventing glove allergies

Answered by Nelson Schlatter, technical applications chemist, Ansell Protective Products, Indianapolis.

Some workers may have a type I latex allergy, which is caused by allergenic proteins that are added to the latex by the rubber trees that make natural rubber latex. Type I allergies can have systemic effects such as coughing, sneezing and rashes on the face, as well as local effects on the skin under the gloves.

These proteins are important in stabilizing the latex as a free-flowing liquid, but they have no further purpose after that liquid has been mixed with other ingredients, applied to hand forms and converted into gloves. Newly made gloves are leached, which removes much of the leftover protein.

Manufacturers have been successful in improving the leaching procedure to reduce the residual amounts of allergenic proteins in gloves. Newer gloves are, therefore, much less likely to cause workers to develop allergies. But it is impossible to remove the proteins entirely. They still may trigger reactions in workers who already have become allergic. Workers who know or suspect they have a latex allergy should consider switching to a synthetic alternative such as nitrile, neoprene or vinyl gloves.

Allergic reactions to nitrile and neoprene are less common than allergic reactions to natural latex. They are commonly type IV reactions, which are caused by a different biological pathway and which can affect only the skin under the gloves. As is the case with latex gloves, the rubber itself is unlikely to cause reactions. For nitrile and neoprene gloves, the usual culprits are additive chemicals called accelerators. Accelerators bear this name because of their effects on the chemical reactions that change liquid rubber formulations into tough rubber films. Accelerator-free nitrile and neoprene gloves are available for use by people who are highly sensitive to these additives.

Allergic reactions to vinyl gloves are almost nonexistent. Most of the time, the problem is contact urticaria, which is a simple skin irritation caused by perspiration and lack of ventilation inside the glove.

Contact urticaria may occur with other types of gloves as well; the risk cannot be avoided when gloves are sealed to keep chemicals out. Sweat-absorbing fabric liners can reduce that risk, with the liners either built into the gloves or worn as separate items under disposable gloves. Adding liners, however, makes the hand protection thicker and reduces the dexterity, which is one of the primary reasons for wearing thin disposable gloves.

Leakage is another possible cause of skin reactions. Although thin vinyl gloves exhibit resistance to many chemicals when tested in the laboratory, reports indicate that when the gloves are donned and worn for about an hour, they will begin to leak. The "allergies," therefore, may be a reaction to the chemicals being handled.

In the unlikely circumstance that workers actually are allergic to vinyl gloves, they should change to natural or synthetic (neoprene or nitrile) gloves, which use entirely different additives. Workers who are allergic only to plastics additives are unlikely to react to rubber additives.