Differentiation of Latex Allergy From Irritant Contact Dermatitis

Latex allergy is an all-encompassing term used to describe hypersensitivity reactions to products containing natural rubber latex from the Hevea brasiliensis tree and affects approximately 1% to 2% of the general population.¹ Although latex gloves are the most widely known culprits, several other commonly used products can contain natural rubber latex, including adhesive tape, balloons, condoms, rubber bands, paint, tourniquets, electrode pads, and Foley catheters.² The term latex allergy often is used as a general diagnosis, but there are in fact 3 distinct mechanisms by which individuals may develop an adverse reaction to latex-containing products: irritant contact dermatitis, allergic contact dermatitis (type IV hypersensitivity) and true latex allergy (type I hypersensitivity).

Irritant Contact Dermatitis

Irritant contact dermatitis, a nonimmunologic reaction, occurs due to mechanical factors (eg, friction) or contact with chemicals, which can have irritating and dehydrating effects. Individuals with irritant contact dermatitis do not have true latex allergy and will not necessarily develop a reaction to products containing natural rubber latex. Incorrectly attributing these irritant contact dermatitis reactions to latex allergy and simply advising patients to avoid all latex products (eg, use nitrile gloves rather than latex gloves) will not address the underlying problem. Rather, these patients must be informed that the dermatitis is a result of a disruption to the natural, protective skin barrier and not an allergic reaction.

Allergic Contact Dermatitis

Allergic contact dermatitis to rubber is caused by a type IV (delayed) hypersensitivity reaction and is the result of exposure to the accelerators present in rubber products in sensitive individuals. Individuals experiencing this type of reaction typically develop localized erythema, pruritus, and urticarial lesions 48 hours after exposure.³ Incorrectly labeling this problem as latex allergy and recommending nonlatex rubber substitutes (eg, hypoallergenic gloves) likely will not be effective, as these nonlatex replacement products contain the same accelerators as do latex gloves.

True Latex Allergy

The most severe form of latex allergy, often referred to as true latex allergy, is caused by a type I (immediate) hypersensitivity reaction mediated by immunoglobulin E (IgE) antibodies. Individuals experiencing this type of reaction have a systemic response to latex proteins that may result in fulminant anaphylaxis. Individuals with true latex allergy must absolutely avoid latex products, and substituting nonlatex products is the most effective approach.

Latex Reactions in Medical Practice

The varying propensity of certain populations to develop latex allergy has been well documented; for example, the prevalence of hypersensitivity in patients with spina bifida ranges from 20% to 65%, figures that are much higher than those reported in the general population.³ This hypersensitivity in patients with spina bifida most likely results from repeated exposure to latex products during corrective surgeries and diagnostic procedures early in life. Atopic individuals, such as those with allergic rhinitis, eczema, and asthma, have a 4-fold increased risk for developing latex allergy compared to nonatopic individuals.⁴ The risk of latex allergy among health care workers is increased due to increased exposure to rubber products. One study found that the risk of latex sensitization among health care workers exposed to products containing latex was 4.3%, while the risk in the general population was only 1.37%.¹ Those at highest risk for sensitization include dental assistants, operating room personnel, hospital housekeeping staff, and paramedics or emergency medical technicians.³ However, sensitization documented on laboratory assessment does not reliably correlate with symptomatic allergy, as many patients with a positive IgE test do not show clinical symptoms. Schmid et al⁴ demonstrated that a 1.3% prevalence of clinically symptomatic latex allergy among health care workers may approximate the prevalence of latex allergy in the general population. In a study by Brown et al,⁵ although 12.5% of anesthesiologists were found to be sensitized to latex, only 2.4% had clinically symptomatic allergic reactions.

Testing for Latex Allergy

Several diagnostic tests are available to establish a diagnosis of type I sensitization or true latex allergy. Skin prick testing is an in vivo assay and is the gold standard for diagnosing IgE-mediated type I hypersensitivity to latex. The test involves pricking the skin of the forearm and applying a commercial extract of nonammoniated latex to monitor for development of a wheal within several minutes. The skin prick test should be performed in a health care setting equipped with oxygen, epinephrine, and latex-free resuscitation equipment in case of anaphylaxis following exposure. Although latex skin prick testing is the gold standard, it is rarely performed in the United States because there is no US Food and Drug Administration–approved natural rubber latex reagent.³ Consequently, physicians who wish to perform skin prick testing for latex allergy are forced to develop improvised reagents from the H brasiliensis tree itself or from highly allergenic latex gloves. Standardized latex allergens are commercially available in Europe.