Latex Sensitivity Redefines an Industry

June 1, 2000
Dentistry`s effort to minimize concerns over allergic reactions includes staff members developing a better awareness of latex products.

Dentistry`s effort to minimize concerns over allergic reactions includes staff members developing a better awareness of latex products.

Tito Aldape

Dentistry has specific concerns about latex sensitivity. The issue of latex sensitivity in dental offices, however, is also part of a larger issue involving many facets of an evolving industry. Here is an overview of how latex sensitivity is shaping the glove business.

In recent years, health-care professionals and the general public have become increasingly concerned with the hazards of blood-borne pathogens, and their mode of transmission. As a result, an increased use of barriers against infection and disease transmission has become necessary. Latex medical gloves provide a primary form of barrier protection for the user. However, also in recent years, some have voiced concerns about the potential relationship between latex medical gloves and latex sensitivity.

Many protective gloves used in medical, laboratory, household, and industrial applications are made of natural rubber latex (NRL). NRL is a highly durable and flexible material that provides a high measure of protection against many blood-borne pathogens and environmental contaminants.

Latex is a milky substance taken from the rubber tree, Hevea brasiliensis, by tapping its bark. Latex is used in the manufacture of many products, including many medical devices. It has been estimated that these products contain 2 to 3 percent latex proteins. Such proteins originate from the rubber tree and are found in raw latex. They may be eluted from a variety of manufactured products such as medical gloves, catheters, condoms, and other medical devices, as well as from nonmedical rubber products such as household gloves, baby pacifiers, and toy balloons.

The latex proteins that are the greatest concern are those proteins that may have the potential to cause allergic sensitization and/or allergic reactions. Unfortunately, not all potentially allergenic proteins in NRL have been identified, and there is no consensus among scientists about which allergenic proteins are the most important.

The study of latex allergy and its possible relationship to the use of NRL gloves is relatively new. The earliest reported medical journal article identifying a possible connection between NRL gloves and latex allergy was published only 20 years ago. Scientists still do not fully understand why the immunological systems of certain people - a relatively small minority - become sensitized to latex, or why an even smaller number of them start exhibiting allergic symptoms when exposed to latex.

Ficus benjamina, a member of the Moraceae family, is a tropical, non-flowering green plant widely used for ornamental purposes in private and public buildings, including offices and hospitals. It is known to be an occupational allergen among plant-keepers, but sensitization is also increasingly found in non-occupationally exposed atopic and non-atopic people. The allergen of Ficus benjamina is located in the plant sap, a type of latex. This finding is significant because there is evidence to suggest that there may be cross-reactivity between the latex proteins of the Ficus benjamina and the latex proteins from the rubber tree Hevea brasiliensis, a member of the Euphorbiaceae family.

The phenomenon of cross-reacting allergies has been known for many years. A cross-reaction occurs when a person sensitized to one allergenic protein experiences an allergic reaction to another protein to which the person is not truly sensitized. This cross-reaction is believed to occur because the proteins have such similar molecular structures that the person`s immune system cannot distinguish between them. Latex has been found to be cross-reactive with many other potentially allergic substances. These include fruits such as avocados, bananas, chestnuts, kiwis, papayas, and peaches. Latex is also believed to cross-react with grass pollens and dust mites.

Latex allergy is a hypersensitivity response to allergens in natural latex products. The pathogenesis of latex sensitivity is not fully known or fully understood. Also, the immune mechanism of latex allergy is not fully understood. It has been suggested that an awareness of the course of events leading to latex allergy may be of importance in understanding the disease and may be helpful in its effective management.

The related article describes reactions that may occur within the dental setting.

Only a physician can diagnose a latex sensitivity condition and prescribe a long-term management program. It is strongly recommended that a physician be consulted if an adverse reaction is experienced through the use of a latex product (latex medical gloves), and that contact with latex products be avoided until a physician resolves the concern.

Some reports suggest that systemic allergic reactions upon exposure to latex have occurred during surgical and other invasive procedures, both in children and adult patients. Allergic reactions are reported to be even more frequent in patients with histories of spina bifida. Other reports claim that atopic individuals have an increased risk of developing a latex hypersensitivity. It appears that genetic predisposition is one of the key factors in determining rates of sensitization to latex in varied populations and patient groups.

Every day, medical gloves must meet more stringent regulatory and quality guidelines, set forth by FDA and ASTM, respectively (see Infection Control Today, July 1999). There are growing demands on the medical glove supplier to provide higher quality products and have greater substantiated data to support product quality.

Medical glove suppliers must be fully aware of the concerns and needs their customers have with regard to latex sensitivity. They must also be committed to providing their customers with superior latex gloves, and to offering superior synthetic medical glove alternatives. It is just as important for health-care institutions purchasing medical gloves to partner with a responsive and well-informed medical glove supplier. The relationship between supplier and buyer has never been more critical, as the decision to purchase medical gloves requires a thorough understanding of:

Y End-user needs

Y Technical glove data

Y Appropriate applications for glove use

Y Glove types

Y Vendor accessibility.

Today, the medical glove supplier is charged with a formidable task of meeting the growing hand protection and barrier protection needs of all glove wearers.

Tito Aldape is vice president of QA/RA and scientific affairs at Microflex Corp.

References available upon request.

Identifying reactions to latex

Adverse reactions associated with the use of latex typically manifest themselves in three distinct forms:

- Irritation

- Delayed hypersensitivity (Type IV or chemical allergy)

- Immediate hypersensitivity (Type I, IgE - mediated immediate hypersensitivity or protein allergy)

* Irritation, also known as irritant contact dermatitis, is a non-allergic response to a wide range of irritants. These can include residual processing substances used in the manufacture of NRL gloves. The condition is usually reversible. Symptoms of this condition include reddening of the skin, or a rash on the skin that tends to be dry and itchy. The onset of this non-allergic response typically occurs within minutes to hours of contact with the gloves and normally only affects the areas of the body that were in direct contact with them.

It is important to note that this condition can be caused by a variety of factors, including chemicals used in the manufacture of gloves. These same chemicals are found in a variety of other products and are definitely not exclusive to natural latex products. Sometimes, irritant reactions aren`t caused by the gloves at all but are the result of exposure to other irritating substances, such as skin-cleansing agents, disinfecting agents, and preservatives.

The use of powder-free latex examination gloves or 100 percent synthetic examination gloves may help alleviate adverse reactions associated with an irritation.

* Delayed hypersensitivity (Type IV), also known as allergic contact dermatitis and chemical allergy, is predominantly an allergic response to residual accelerating and/or processing agents used in the manufacturing process of latex products.

The severity of this type of response is extremely varied. It typically affects the skin and can be characterized by a red rash, small blisters, dry thickened (leathery) skin, crusting, scabbing sores, and peeling. The onset of this response is delayed, typically occurring between six and 48 hours after contact. A wide area of the body may be affected, resulting in a condition that is not limited to the areas that came into direct contact with the NRL gloves.

The use of a powder-free latex examination glove with a reduced protein label claim, or a 100 percent synthetic alternative powder-free examination glove, may help alleviate adverse reactions associated with residual accelerating/processing agents.

* Immediate type sensitivity (Type I), also known as an Immunoglobulin E (IgE) mediated hypersensitivity and protein allergy, is an allergic response to residual water extractable proteins found on finished latex devices made of NRL. These proteins originate from the rubber tree (Hevea brasiliensis) and are considered to be significant antigens associated with this type of allergic condition.

The severity of this type of response is extremely varied and can be serious. It is typically characterized by local or generalized urticaria, rhinitis, conjunctivitis, asthma, or anaphylaxis. The onset of this response is immediate, typically occurring within a few minutes to one hour after contact. The areas of the body affected by the NRL gloves are undefined and not limited to the areas coming into direct contact with the product. As a result, there is a potential for other parts of the body beyond the area of contact to be affected.

Studies have shown that users of latex products who suffer from immediate onset hypersensitivity (Type I) are often atopic, and already exhibit allergic responses to a number of other substances/chemicals. Studies also indicate a potential for systemic involvement. Contact with any latex product must be avoided by one who suffers from immediate type sensitivity to latex. Anyone who suspects he or she may have a Type I allergy to latex should consult a physician.

The use of a 100 percent synthetic medical glove may help alleviate adverse reactions associated with latex proteins.

Only a physician can diagnose a latex sensitivity condition and prescribe a long-term management program.