Latex allergy can induce clinical reactions to specific foods

D.H. Beezhold et al.

Glossary:

Anaphylaxis: a general, rather than local, allergic reaction characterized by difficulty breathing, wheezing, a shock-like state, or any combination of these symptoms.

The precise ingredients of natural rubber latex that cause allergic reactions have not all been identified, although some, such as the enzyme rubber elongating factor and the proteins havamine and hevein preprotein, are known. The reaction to these elements is caused, like many allergic reactions, by the antibody immunoglobulin E (IgE), and the symptoms of allergy can range from contact urticaria (hives) all the way up to anaphylactic shock, which can be and has been fatal in some cases. Hay fever-like symptoms such as conjunctivitis and rhinitis are also frequently seen.

Latex-sensitive people seem to have much higher rates of allergy to certain foods than the general public. But no study until now concerned itself with measuring the correlation and finding the reason behind it. This study looked at 47 latex allergy sufferers and compared them with 46 non-sufferers in a battery of reactivity tests with different foods in a controlled environment. As one might expect in a latex allergy study, 41 out of 47 allergic subjects were health-care workers. As other studies have found, the majority were women. Of the 46 controls, 25 were atopic, meaning that they had a genetic predisposition to other allergies mediated by the same IgE antibody that causes latex allergy such as hay fever, asthma and allergic dermatitis. They were not, however, sensitive to latex. The 21 additional controls were not atopic.

Skin prick tests were carried out on the arm using solutions of allergens known to appear in latex, as well as in avocado, banana, chestnut, kiwi, milk, pineapple, potato and tomato. Results clearly showed that latex allergy predisposes people to allergic reactions to one or more of these foods. Seventy percent (33/47) of latex-sensitivepatients reacted to one or more foods, while only 15% (7/46) of the control patients showed any abnormal skin tests.

Avocado caused 25 positive skin reactions among the latex-sensitive group, and was the most common allergen, followed by potato and banana. In addition to positive skin tests, there were 27 reactions with clinical symptoms among the latex-sensitive group, varying from local pruritis (itchy rash) of the hands and mouth, most common with potato, to anaphylactic reactions, most common with banana.

The test demonstrated that latex allergy links to sensitivity to avocado, banana, chestnut and kiwi are true in varying degrees, and revealed a previously undocumented link to tomato and potato. Pineapple and milk sensitivity were not found to be related to latex allergy. Most of the positive skin tests were not accompanied by clinical symptoms of allergy and should not therefore be seen as too alarming, though those test subjects who had them should be monitored in the future to see if reactivity becomes more pronounced. It would appear that food allergies are a consequence oflatex allergy, or at least appear after latex allergy in most cases, though this may be the other way around in a few instances.

Clearly, the danger of anaphylactic food reactions is much greater in latex-sensitive individuals than in the general population or even the wider atopic population. Careful testing for possible food allergies is therefore recommended in cases of demonstrated latex allergy.

Questions for Dr. Beezhold:
1. Does a more serious anaphylactic reaction to latex suggest a more serious anaphylactic reaction to certain foods?
Certainly, there is a good deal of cross reactivity among latex-allergic people with foods that contain similar allergenic proteins, such as banana, avocado, chestnut, and so on. There's a potential for anaphylactic reaction there, though not all latex-allergic individuals have the cross reaction. Among those who do cross react, it's generally true that those who have a severe anaphylactic reaction to latex are more likely to have a severe anaphylactic reaction to similar allergens in food.

2. Can allergies to latex or related plant proteins recede with time if the offending substance is avoided?
There's evidence that if you totally avoid the allergen the level of your anti-latex IgE (immunoglobulin E) which mediates the allergy will subside over time. It doesn't mean that you're free of the allergy, and if you are re-exposed to latex you may at first have a mild reaction gradually becoming more severe as exposures increase.

3. Is it normal for allergy to latex and related proteins to become more severe with time?
If you're exposed continually, then the evidence suggests that it will tend to become more severe each time. What we suspect and are somewhat concerned about is that the potential is always there for latex hypersensitivity to become severe enough to reach dangerous anaphylactic reactions.

4. Does a positive skin test without symptomatic reaction mean it would be wiser to avoid the food that produced it?
It certainly would be wiser. We don't really know what to do with the skin test-positive asymptomatic people.
Certainly the risk of a severe reaction is always there, so it's better not to take chances.

5. Can cooking remove the danger from some foods, and if so, how does it work?
It appears to remove or lessen the danger in some cases. Certainly, there are people who would react to potato in the raw state but who are able to eat it when it's cooked. Other people have commented that they seem to have less of a problem with bananas that are very ripe. This is because the allergenic protein breaks down over time, and that process is compressed into a very short time when food is cooked, which means it's easier to tolerate. This is true of most of the food allergens where there is cross reaction with latex. However, there are some allergens which are heat-stable and cooking doesn't destroy them.

Comment from Dr. Beezhold:

Latex allergy has been fatal. The widely quoted number is 15 deaths reported to the FDC, but there have in fact been several more which haven't yet been recorded as such because of lawsuits. The number might well be higher, except for the fact that so many victims of latex allergy are health-care workers who have become sensitized through constant contact with latex surgical gloves, and they tend to have anaphylactic reactions in places with emergency facilities, or they are sufficiently well-informed about their condition to carry an epipen (a disposable syringe used for emergency injection following exposure to a dangerous allergen) and inject themselves. There are people who are almost incredibly sensitive to latex, and can detect it in the handle of a squash racket, or in a gym floor or carpeting, or in an elastic band in socks or underwear.

For people in this condition, life is radically affected. They have to stay in their house much of the time, only going out on certain occasions and then taking great care of what they touch and where they go, because this substance is everywhere. In the literature there's a mention of 40,000 consumer products that contain latex. Even though a latex substitute exists and is used in some surgical gloves, it is expensive and in some cases less well-suited to the tasks it performs. I don't think that synthetics are about to replace natural rubber latex as long as there are millions of trees churning this substance out; it's tough to compete with the natural product.

Latex allergy can induce clinical reactions to specific foods.

D.H. Beezhold, G.L. Sussman, G.M. Liss, N.-S. Chang

Objective: The purpose of this study was to investigate crossreactivity between latex and foods, to identify crossreacting IgE binding proteins, and to assess the clinical significance.

Methods: Forty-seven latex allergic patients and 46 non-latex allergic patient controls were studied. Allergen sensitization was determined by skin-prick testing (SPT) and allergenic proteins were identified by immunoblot reactivity and amino acid sequence analysis.

Results: Immunological reactivity to foods was found to be common, occurring in 33 latex-allergic individuals but in only seven controls (p0.000001); 100 of 376 (27%) food skin-prick tests were positive in the latex-allergic subjects. Twenty-seven out of 100 positive food SPTs were associated with clinical symptoms. Seventeen patientsmanifested a clinical allergy to at least one food including 11 with anaphylaxis and 14 with local sensitivity reactions.

Positive food skin tests occurred most frequently with avocado (53%), potato (40%), banana (38%), tomato (28%), chestnut (28%), and kiwi (17%). Latex-allergic patients (23%) recognize a protein that had sequence homology to a broad class of plant proteins known as patatins. Crossreactivity between latex and several potato proteins was observed by immunoblot inhibition analysis.

Conclusions: Sensitization to latex has extensive crossreactivity with certain foods and leads to clinical allergic reactions. Potatoes and tomatoes are newly reported crossreacting foods. Plant proteins with structural homology to latex proteins may predispose to food allergy.

By D H. Beezhold and G.L. Sussman, G.M. Liss, N.-S. Chang
Published in Clinical and Experimental Allergy Journal1996;26:416-22,