Rash Decisions

In the research laboratory, especially where chemicals are involved, gloves are our primary defense in preventing exposure to and contact with harmful agents. Since the introduction of “universal precautions” for safeguarding against blood-borne pathogens, glove use has grown exponentially. In most laboratories, use of the latex examination glove has become the norm. But for some workers, wearing disposable latex gloves may produce allergic reactions. Reports on the prevalence of latex allergy vary greatly. Recent scientific literature indicates rates up to 11 percent for non-health care workers exposed to latex at work.¹ Read on to learn the causes, symptoms, treatment and prevention of latex allergy and associated dermatitis reactions.

What is latex and what is latex allergy?

Natural rubber latex, referred to as “latex,” is the product manufactured from the milky sap extracted from the rubber tree, Hevea Brasiliensis, found predominately in Africa and Southeast Asia. Latex is made up of many chemicals, but the proteins found in the rubber are the culprits leading to the more serious allergic reactions. The manufacturing process can remove most of these proteins. However, due to the huge demand, many poorquality gloves have reached the market. Additionally, the manufacturing processes use organic chemicals, including carbamates, mercaptobenzothiazole and thiurams as acceleration agents, further increasing the potential for allergic reactions for workers wearing latex gloves.

Simply stated, latex allergy is a reaction to the proteins in latex rubber. It is unknown how much exposure is needed to produce an allergic reaction or sensitization, but increasing the exposure increases the risk of developing symptoms. Fortunately, true latex allergy is rare, as you will see. Unfortunately, there are two other types of reactions that can occur and these are much more prevalent.

Different latex reactions

The single most common reaction to latex products is called irritant contact dermatitis (ICD), which is also known as eczema or just dermatitis. As the name indicates, this type of reaction is caused by irritation from wearing and using protective gloves and by exposure to the powders inside them. It is not caused by an allergy to the latex proteins or other chemicals contained in the latex. Frequent use of antiseptic or germicidal agents, or constant washing and drying of the hands, may deplete the natural oils and dry out the skin. The alkaline nature of many soaps acts to strip away the protective acid mantle of the skin. Sweating and rubbing also contribute to skin irritation. Finally, the powders added to gloves for easier donning are one of the leading causes of ICD.

Symptoms of ICD often include dry, itchy, cracked, scaly skin, usually on the hands. Redness, swelling and blistering may also occur. Symptoms are usually limited to the areas covered by the gloves.

Allergic contact dermatitis is sometimes called chemical sensitivity dermatitis (CSD). It is a response to the chemical accelerants in the latex mentioned above, which are referred to as contact sensitizers. Other common contact sensitizers include disinfecting agents and soaps. Technically referred to as Type IV delayed hypersensitivity, CSD appears as a rash with blisters (similar to poison ivy) and usually peaks within 48 hours. People with chronic skin damage are at increased risk, and with repeated contact progression spreads beyond the border of the gloves. Neither chemical sensitivity dermatitis nor irritant contact dermatitis is a true allergy.

True latex allergy, technically named immediate Type I hypersensitivity, can produce severe reactions in workers exposed to latex. Auspiciously, it is much less common than the dermatitis reactions. A Type 1 reaction is a systemic response caused by repeated exposure to a specific allergen (i.e., the latex proteins). Triggered by exposure to some threshold level, a flood of histamine and other factors are released, causing vasodilatation and bronchoconstriction. Symptoms usually begin within minutes of exposure in sensitized persons, but they can occur hours later and be widely varied. Skin flushing, rashes, hives or itching are examples of mild reactions. Severe reactions include itchy swollen eyes, runny nose, sneezing, scratchy throat and asthma (difficult breathing, coughing and wheezing). Very rarely, anaphylactic shock has occurred, but this is seldom the first sign of latex allergy.

Damaged or broken skin can increase the risk for latex allergy, and in many cases, workers contract the dermatitis before developing the latex allergy. Also, a link has been demonstrated between increased susceptibility to latex protein allergy and allergic reactions to certain foods, such as avocados, kiwis, bananas, tomatoes and papayas. Absorption through the skin, the dermal route, is not the only exposure means for latex proteins. Breathing in the particles, the inhalation route, is possible as the proteins can become attached to the powders and then dispersed when the gloves are donned or removed. This can be a concern for any sensitized individual who happens to breathe the airborne particles.

Treatment and prevention

The key to preventing long-term health effects is detecting symptoms early. Seek proper medical attention at the first signs of trouble. Medications are available to treat the symptoms, but complete latex avoidance is the most effective strategy. Special precautions are necessary to prevent subsequent exposures once a worker develops latex allergy.

Workers are often unaware of latex allergy risk in the workplace. This can result in potentially serious health problems. Minimize risk and prevent possible health problems by following these recommendations from NIOSH:²

Use non-latex gloves (such as nitrile, PVC) whenever possible (e.g., working with noninfectious materials, doing routine housekeeping, etc.).
If latex gloves are the best choice, use powder-free gloves with reduced protein (<50 micro-grams/gram extractable protein) and low levels of residual chemical accelerants.
Develop and implement appropriate safe work practices to reduce chances of latex exposure.
Develop and provide training to employees on latex allergy.
Learn to recognize the symptoms of latex allergy.

References

Preventing Allergic Reactions to Natural Rubber Latex in the Workplace, NIOSH (National Institute of Occupational Safety and Health): Publication #97-135, June 1997.
Latex Allergy A Prevention Guide, NIOSH (National Institute of Occupational Safety and Health): Publication #98-113, 1998.