Are your gloves making you sick? In this article, South African allergy expert Dr Harris Steinman helps us to understand the issues with latex sensitivities and the implications for the food industry.
In the late 1980s to early 1990s, there was a dramatic increase in the recognition of latex sensitivity. This coincided with the increased use of latex gloves, resulting from the AIDS/HIV epidemic. The implementation of preventative measures, including the introduction of powder-free low-allergen latex gloves and their replacement with nitrile and vinyl gloves, has seen a steady decline in the prevalence of latex allergy.
Although healthcare workers were the most commonly affected, probably due to their greater exposure frequency, exposure to natural rubber latex (NRL) from Hevea brasiliensis still constitutes an occupational hazard for workers in other sectors, including the food industry. A Spanish study suggested that latex allergy might be as common among food workers as among healthcare workers.
In the food industry, the occupations involved stretch from farm to fork, and include greenhouse workers, cleaners, food handlers, bakers, chefs, deli-counter operators, food developers, laboratory technicians, and so on.
Contrary to the popular perception that latex gloves are the only cause of exposure to latex, many other consumer and commercial latex-containing products may also be sources of exposure. These include kitchen tools, packaging materials and rubber boots; and for many food-industry workers, sources may be present at home as well, including condoms, elastic, swimming caps, mattresses, duct tape, and even babies’ dummies.
Latex allergens may be transferred from gloves or other sources to other items, including foods and salads. Examples of unusual contact with latex include individuals who have experienced: impaired swallowing, breathing and speaking after eating peeled shrimps, fish and salad or bread, attributed to latex contamination of the food product; contact urticaria, from latex in chocolate-bar wrappers; and anaphylaxis to latex, after eating a cream-filled doughnut contaminated with latex. Direct transfer of latex protein to sliced cheese and lettuce touched by a gloved finger has also been documented.
A common and mistaken belief is that allergy to latex gloves occurs from contact with latex alone. However, latex and latex gloves contain a number of rubber additives and irritant chemicals. Gloves may contain corn starch or casein, to facilitate the donning of gloves. These additional ingredients may also result in allergic, irritant or other types of reactions. Exposure to latex and associated allergens can occur via direct contact or airborne exposure.
Although there are a range of types of reactions to latex, three predominate: Irritant contact dermatitis, allergic contact dermatitis (type IV (delayed) hypersensitivity), and IgE-mediated allergy (type I or immediate hypersensitivity). It is important to appreciate the differences between the three, since latex protein avoidance is critical to those who have latex allergy.
Irritant dermatitis is the most frequently observed reaction to latex products, and accounts for 80% of work-related reactions to latex gloves. The drying action of the corn starch and/or other irritant chemicals found in gloves contributes to this condition, and may be exacerbated by soap and mechanical irritation. The resulting disruption of skin integrity may enhance latex protein allergen absorption, and result in latex allergy.
Allergic contact dermatitis is usually an allergic reaction to chemicals used to make gloves, rather than to proteins from the natural rubber itself. Numerous chemicals are used in the manufacturing process, including antioxidants, emulsifiers, stabilisers, accelerators, stiffeners, colourants and fragrances, and any of these may cause contact dermatitis 24 to 48 hours after exposure.
IgE-mediated allergic reactions to latex proteins include eczema (atopic dermatitis), contact urticaria (hives), rhinitis (runny nose), conjunctivitis, asthma and anaphylaxis (shock). Reactions usually begin within minutes of exposure; but the clinical manifestations vary greatly, depending on the route of exposure, the amount of allergen, the degree of sensitisation, and other individual factors.
Other reactions seen include respiratory irritation, eye irritation, and abnormal pulmonary function tests. These reactions may not be based on an allergy mechanism.
Latex allergy may be confused with protein contact dermatitis, which results from direct contact with fruit and vegetables, e.g. working with garlic, onions, etc.
Latex is not a single allergen, but contains at least 15 proteins that can act as allergens. These include rubber elongation factor, enolase, and lipid-transfer protein. The relevance of this is that these proteins belong to protein families that may occur in other foods; and therefore, being allergic to a particular latex protein may result in cross-reactivity with a similar protein in another food. For example, the latex allergen Hev b 5 shows similarly with a protein in kiwi fruit; Hev b 6.02 is a chitinase protein, and similar chitinase proteins are found in banana, avocado and chestnut, thus giving rise to the latex-fruit syndrome.
The implication of this is that depending which of the latex proteins an individual is allergic to, allergy reactions may also be experienced with the food containing a similar allergen – e.g. a latex-allergic worker may also be allergic to banana, avocado, kiwi or mango, and vice versa. The spectrum of clinical reactions may be very wide; banana, avocado, chestnut and kiwi have been associated with anaphylaxis, whereas potatoes usually elicit mild local reactions.
Diagnosis of occupational latex allergy involves the health professional taking a very good history, followed by skin, patch or blood tests. Respiratory symptoms may require lung tests.
There is no cure or treatment for latex allergy: the only answer is avoidance of latex-containing products. Individuals who have experienced anaphylaxis to latex must take extreme precautionary measures, and may have to change occupations. In some sectors of the food industry, there has been a move to replace latex gloves with alternatives. Several US states, such as Oregon, have banned latex-glove use in the food industry.
For workers experiencing severe symptoms, the diagnosis may be made fairly quickly; for those with chronic symptoms, it may not. But for all workers exposed to latex, the risk of becoming initially sensitised, followed by allergic, remains a risk.
So what to do if gloves are unavoidable:
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