Airborne Latex

There is a large American literature on "airborne latex protein particles" which it is alleged are liable cause respiratory problems in those who are prone to allergic responses. Taken at face value these reports would appear to be remarkable indeed. Most attempts at the production of powdered natural rubber have failed because of agglomeration.

Rubber articles tend to stick together and for this reason are dusted. In the case of latex gloves, many are dusted with cornstarch powder and its is the corn starch powder which is capable of acting as a carrier for some of the proteins on the surface of rubber articles which cause the respiratory problems. Allergic reactions to flour dust are relatively common; thus one would expect corn powder to have a similar potential for allergic reactions.

Thus, the American literature should really be about cornstarch particles to which latex proteins have adhered. One may be tempted to consider that as "corn" is one of the staple products of American agriculture then American writers are loath to cause offense to that powerful lobby. Thus US researchers appear to favour bending the laws of physics rather than offending their farmers. Another factor which enters into the alleged airborne latex problem is that it appears to manifest itself mainly in the USA and may have much to do with the climate in Central USA and American air-conditioning which leads to ultra-low humidity levels.

Furthermore, at least some individuals are allergic to cornstarch as such. Two recent papers show how individuals may be allergic to starch used to stiffen clothing¹³, or to starch used as a dusting agent¹⁴ for paper bags. A patient with a history of atopic eczema and multiple immediate sensitivities was seen for a persistent dermatitis of the face, hands, and clothing areas of the trunk and arms. Investigation showed a positive prick test to cornstarch, and avoidance of glove powder and starch in clothing cleared what had been a recalcitrant problem. A paper-bag maker developed severe occupational (protein) contact dermatitis within two-three hours after returning to work.

The patient lacked any evidence of urticaria and demonstrated largely negative patch-test results. Following a history of occupational exposure to a cornstarch-based adhesive, the patient was patch-tested to materials with which she had worked, which she contacted, and with which she had attempted treatment. Following patch testing, she was prick-tested to cornstarch, the principal ingredient in the adhesive. Patch testing was negative except for a very mild reaction to the adhesive. Prick testing to cornstarch was more severe than the histamine control. The test site became eczematous and remained so for more than ten weeks. Avoidance of cornstarch and the adhesive was followed by clearing.

Similarly, the presence of casein in gloves may also give false indications of allergy to latex proteins^15-16. Casein is based upon milk from cows and, like flour and other cereal products, is a relatively common source of allergic responses.

As noted earlier, many of the people "who are allergic to latex" are also allergic to a wide range of other common plant and animal products. Thus such sufferers may also be allergic to bananas, peanuts, chestnuts and so on, but there is a general tendency to label such patients as "sufferers of latex protein allergy" rather than as sufferers of allergic reactions to bananas, peanuts, chestnuts and so on. In effect natural rubber latex has become a guise for those who are also allergic to a wide range of common foodstuffs. This is a very important feature of the problem as some of the measures being proposed to tackle the "latex allergy problem" would not be tolerated if it was transmogrified into a banana problem, or a peanut problem, or a chestnut problem. This is especially significant when considered in relation to some of the US governmental pronouncements on the use of latex gloves in non-medical environments, notably in food-handling.

The OSHA has advocated a limitation in the use of latex gloves to that of acting as a medical barrier, stating that such gloves should not be used for food handling and in a wide variety of industrial applications.

Primary prevention involves reducing potential development of allergy by reducing unnecessary exposure to NRL proteins for all workers. Food service workers or gardeners, for example, do not need to use NRL gloves for food handling or gardening purposes.

These are highly questionable restrictions being set by a nominally governmental organization, and are certainly less valid than European concerns about hormone-treated beef which is permissible in North America, but is considered dangerous in Europe. It must be stressed that not all of these strictures are repeated in the FDA Manual. If the OSHA dictate is intended to protect those are already allergic to latex then this would be on a par with Europe banning all products which might have into contact with American beef. The risk of proteins being transferred from gloves to foods must be minuscule in the extreme and is comparable to "memory in water" and is vastly less than that associated with the risk of peanut pollution in food (an issue on which the OSHA appears to be dumb).

Moreover, it must be observed (in case anyone is tempted to consider that it is a matter of degree) that peanut allergy is responsible for a considerable number of fatalities each year, and that some airlines have banned the distribution of peanuts in flight due to the risk of serious reactions in infants exposed to peanut particles in the cabin atmosphere. On the other hand, it may be noted that the FDA appears to be far more lax on the question of the lethal peanut and its potential for airborne manifestations than on natural rubber latex. If one is generous, then one should note that the FDA does not appear to have advocated the use of peanuts as an essential dietary requirement, whereas it did advocate the use of natural rubber latex for universal barrier protection.

References
¹³Guin J.D. and Styles, A., Protein-contact eczematous reaction to cornstarch in clothing. J. Am. Acad. Dermatol., 1999, 40, 991-4.
¹⁴Guin, J.D., Westfall, C., Ruddell, D. and Caplinger, K., Occupational protein contact dermatitis to cornstarch in a paper adhesive. Am. J. Contact Dermat., 1999, 10, 83-8.
¹⁵Ylitalo, L., Cow's milk casein, a hidden allergen in natural rubber latex gloves. J. Allergy Clin. Immunol., 1999,104, 177-80.
¹⁶Moneret-Vautrin, D.A., Cow's milk allergy. Allerg. Immunol. (Paris), 1999, 31, 201-10.