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Understanding Latex Allergy And Glove Chemistry

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					    Understanding Latex Allergy And Glove Chemistry
By Edward Lehrman, MD (written ~August 29, 1996)

Selecting The Right Glove: Understanding Latex Allergy And Glove Chemistry
Over the past few years, there has been an increasing incidence of allergic reactions among
health care workers to latex medical gloves. Current estimates on the prevalence of latex
allergy among health care workers range as high as 17%. This is thought to be largely due to
the institution of universal precautions in response to the AIDS epidemic, and the resultant
dramatic increase in glove usage. A large body of literature on this subject has built up in the
allergy, immunology, and nursing journals, but there have been relatively few publications in
the surgical literature, so many surgeons and surgical subspecialists remain relatively
ignorant in this area. This review will summarize the most important findings from this
literature from the point of view of the glove user (the surgeon and nurse). A major theme of
this monograph is that a latex glove, like all medical devices, has benefits as well as risks.
There are potential side effects from this device, and the surgeon needs to consider these in
making his or her choice of surgical glove. I hope to cover:
           1. What characteristics should we look for in a glove?
           2. What types of allergic reactions can occur?
           3. Basic information about rubber (natural latex and synthetic) and how gloves are made
You should understand what it is that you are putting against your skin. It is important to
consider the risk of allergic sensitization when selecting gloves rather than just choosing the
lowest cost item available, or simply relying on the hospital purchasing department to make
the appropriate choice for you. I am going to focus on sterile gloves for use in surgery, but
remember that non-sterile examination gloves for use in the office are important to evaluate
as well.



What glove characteristics should we look for?
There are several important considerations. First, gloves offer barrier protection both for the
health care worker and the patient to guard against contact with blood, other body fluids, and
microorganisms. Latex has been in use for about 100 years, and has proven barrier
protective capability. In a series of studies, Korniewicz and co-workers9,10,11 have shown that
vinyl gloves have higher leakage rates than latex (less barrier effectiveness), and are
therefore less suitable for surgery. They reported that although both vinyl and latex
examination gloves provide protection to the user, latex gloves maintain their integrity longer
under in-use conditions. The barrier effectiveness of synthetic rubber gloves is not as well
established at this time as for latex. 18
Second, a glove needs to be comfortable. One should be able to don it (slip one’ s hand into
it) easily, and then be able to perform surgery as if you weren’ t even wearing a glove at all.
Again, latex excels - the synthetic materials are frequently stiffer than latex, and less
comfortable to wear.
Third, cost is important. Latex gloves are usually less expensive than synthetic rubber
gloves.
So latex has substantial benefits as a material for surgical gloves. What are the risks?



Latex Allergy
A latex glove contains natural latex, cornstarch powder frequently (added to help the surgeon
don the glove), and numerous chemicals, some of which will be discussed below. These are
foreign matter, and the human immune system sometimes responds. There are 3 major
types of reactions.
   1. Irritant dermatitis - This is skin irritation that does not involve the body’s immune response. It
      is not an allergic response. Some causes include: frequent hand washing and inadequate drying,
      aggressive scrubbing technique or detergents, mechanical abrasive effect of glove powder,
      climatic irritation (cold climates can cause dry, chapped skin and hot weather can cause
      excessive sweating), and emotional stress. Even though this is not an allergic reaction, irritant
      hand dermatitis can cause breaks in the skin which can allow easier entry of the sensitizing
      latex protein or glove chemicals, and in turn lead to latex allergy. Fay 5 provides a review of
      irritant dermatitis and its management.

   2. Delayed cutaneous hypersensitivity (type IV allergy) - This is a contact (hand) dermatitis
      generally due to the chemicals used in latex glove production. It is mediated via T -cells. The
      skin reaction is typically seen 6-48 hours after contact. The reaction is local and limited to the
      skin that has contacted the glove. While not life threatening, those with type IV allergy are at
      increased risk to develop type I allergy. One route of sensitization, for example, is that latex
      proteins are more easily able to enter the body through the broken skin barrier.
   3. Immediate reaction (type I allergy) - These are systemic allergic reactions caused by
      circulating IgE antibodies to the proteins in natural latex. Symptoms include hives, rhinitis,
      conjunctivitis, asthma due to bronchoconstriction, and in severe cases anaphylaxis and
      hypotension. Symptoms occur soon after exposure to latex (within about 30 minutes). There
      are several routes of exposure that can lead to type I sensitivity: cutaneous, mucosal,
      parenteral, and aerosol (from inhaling latex glove powder).
There are several groups of people known to be at increased risk for latex allergy: patients
who have had multiple hospitalizations and been exposed numerous times to latex medical
products (especially patients with spina bifida), health care workers, and workers in the
rubber industry. Current estimates are that 8-17% of health care workers become sensitized.
The recent emphasis on universal precautions, with a concomitant marked increase in glove
usage, is largely blamed for the increase in allergy among health care workers. Atopic
individuals (those with other allergies or asthma) are at significantly greater risk to develop
latex allergy than the general population. It is estimated that as many as 25-30% of atopic
health care workers may become sensitized.
Another major issue is the cornstarch powder that has long been used in latex gloves.
Researchers have shown in several papers 3,4 that cornstarch powder binds the latex protein
in the surgical glove, which allows the antigen to reach both the wearer’ s skin more easily
(when the hand becomes moist during surgery) and the patient’ s skin. Also, when the
surgeon both dons and removes the glove, cornstarch powder is released into the air, and
this becomes a significant source of aerosolized latex protein that can sensitize health care
workers via inhalation. In a separate study done at the Mayo Clinic, 19 latex aeroallergen
concentrations varied from 10 to 208 ng/m 3 in areas where powdered latex gloves were used
compared to 0.3 to 1.8 ng/m3 in areas where powdered latex gloves were never or seldom
used. Donald Beezhold has also written that body sweat inside latex gloves may make latex
proteins soluble, allowing absorption through skin and sensitizing the wearer.4 He has
reported that the amount of free latex protein that can be extracted from powdered latex
gloves is consistently higher than the amount that is liberated from non-powdered gloves. 4,12
He has suggested that cornstarch powdered latex gloves should be eliminated. 2
Here is another thing to remember: not all latex gloves are created equal. There are
significant (sometimes astounding) differences between manufacturers and product lines in
the amount of free latex protein that can be liberated from the glove and the number and
types of chemicals used in glove production. Also, gloves can be soaked after production to
try to leach out the protein and chemicals, and once more there will be differences between
manufacturers in how effectively these are removed. There is literature that clearly shows
that some brands of gloves are more allergenic than others. 21



How are gloves made?
Now on to some material about rubber in general and how gloves are made. 1,14,15,20 This will
be brief - a more detailed review at a level that a physician or nurse can understand is the
article by Truscott.   20   In order to make a surgical glove, in addition to latex, one needs water,
vulcanizing agents, accelerators, activators, blockers, retarders, anti-oxidants, preservatives,
odorants, colorants, stabilizers, and processing aids. In other words, you need a veritable
chemical soup.
Natural latex is a polymer - that is, it is a long molecule composed of many repeating smaller
molecular units. The basic unit of the polymer is called isoprene (synthetic rubbers use
different chemicals as the basis for creating the polymer). Charles Goodyear first discovered
a process that made rubber commercially useful. The story is that he accidentally dropped a
mixture of rubber and sulfur into a fire. This produced a material that was no longer sticky,
and had many desirable physical characteristics. Goodyear named this process
vulcanization, after Vulcan, the Roman god of fire and craftwork. Vulcanized rubber is
stronger yet also more elastic than the starting material. The sulfur cross-links the polymer
chains in the latex. You can stretch vulcanized latex, but the polymer chains then snap back
so the product returns to its original shape.
Nowadays, latex gloves are not produced with sulfur and fire. But sulfur is still very important
as the primary vulcanizing agent. Accelerators are chemicals that speed the cross-linking
process, either by donating sulfur atoms or because they are soluble within the natural
rubber and help to draw the sulfur into the rubber by binding with sulfur. The major
accelerators (and these are very important because they all can cause type IV allergy) are:
thiurams, mercaptobenzothaizoles (usually abbreviated MBTs), and carbamates.
A second group of chemical sensitizers is the anti-oxidants. These are added to decrease the
rate of rubber degradation. A wide variety of chemicals are available - glove manufacturers
primarily use substituted phenols.
It is important to realize that different gloves will have different chemicals in differing
concentrations in the final product. Also, since latex is a natural product, there will be some
variation in the protein content from one lot to the next.
One brief comment about the word hypoallergenic - ignore it. The FDA proposed regulations
in the summer of 1996 (which are not yet finalized as of this writing) that manufacturers not
be permitted to use this term, since there is no established safe level below which latex
protein or glove chemicals might not be harmful.
Gloves are created by dipping forms (which look like hands) into vats of liquid latex and
admixed chemicals. The latex glove then hardens on the mold - it is formed with what will
ultimately be the inside of the glove (touching your skin) on the outside of the mold. Then the
gloves, still on the mold, go through one or more rinses to leach out protein and residual
chemical (better rinsing equals less residua). Finally, the finished product is stripped off the
mold, packaged, and sterilized.



Conclusions
Clearly, we need gloves that provide excellent barrier protection, surgeon comfort, and
acceptable cost. I would add that the literature indicates that the ideal glove, if it is latex,
should be powder free, very low in extractable latex protein, and have the smallest
concentration and the fewest number of residual chemicals from manufacture           6,18   Even when
considering glove selection from the cost side alone, the cost at the time of purchase is only
one part of the equation. As Fay 7 points out, failed (torn) gloves cost the hospital money for
replacement and waste removal, and one needs to consider the very real costs of providing
the more expensive synthetic gloves for workers who become sensitized to latex or the major
costs of disability payments for those who become so seriously sensitized that they are
occupationally disabled.8,18 The risk of serious allergic reactions in patients who are already
sensitized to latex must not be overlooked.
Alternately, the surgeon might consider that perhaps the ideal surgical glove is a synthetic
rubber, such as polychloroprene (Neoprene) or one of the copolymers that contain styrene
and butadiene. But there are pitfalls to this approach as well. The barrier properties of
nonlatex synthetic rubber gloves are not as clearly defined. The cost of the synthetics is
greater. The user still needs to pay attention to the chemical composition of the glove,
because dangerous type IV reactions are possible. And the surgeon who chooses synthetic
rubber gloves should be prepared to potentially sacrifice on glove comfort, dexterity, and grip
because the fit, feel, and elasticity of the synthetic materials differ from natural rubber latex.
Glove choice should also be appropriate to the situation. One should consider wearing non-
latex gloves (such as vinyl) when the superior barrier protection of latex is not needed. So,
for example, a very short (less than 10-15 minute) procedure with minimal prospect for blood
or body fluid contact might be one for which a vinyl glove could be considered an acceptable
choice. Non-latex gloves may also be appropriate for the nurse who preps the surgical site
prior to the start of surgery if the patient’ s skin is intact, making body fluid contact highly
unlikely.
In addition, here are a few common sense reminders. 13 Prior to use, medical gloves should
not be stored under conditions of excess heat or light, nor be near sources of ionizing
radiation, since this will cause more rapid rubber degradation. Health care workers should be
sure to remove gloves promptly when completing a procedure, and then wash his or her
hands after glove use to minimize skin contact time with potential allergens. Also, health care
workers should avoid touching their eyes, noses, or mouths while wearing latex or
immediately upon removing a latex glove, in order to avoid potential latex sensitization via
these mucosal routes.
References
 1. "Barrier protection, the hands on experience: clinical reference manual." Ansell Perry
    Corporation.
 2. Beck, W. & Beezhold, D. Starch glove powder should follow talc into limbo. Journal of the
    American College of Surgeons 178: 185-186, 1994.

 3. Beezhold, D. & Beck, W.C. Surgical glove powders bind latex antigens. Archives of Surgery
    127: 1354-1357, 1992.

 4. Beezhold, D., Kostyal, D., & Wiseman, J. The transfer of protein allergens from latex gloves: a
    study of influencing factors. AORN Journal 59: 605-613, 1994.

 5. Fay, M.F. Hand dermatitis. AORN Journal 54 (3): 451-467, 1991.

 6. Fay, M.F. Gloves: problems, pitfalls, and prevention. Infection Control and Sterilization
    Technology 2 (1): 23-28, 1996.
 7. Fay, M.F. & Dooher, D.T. Surgical gloves: measuring cost and barrier effectiveness. AORN
    Journal 55 (6): 1500-1519, 1992.

 8. "Guidelines for latex glove users." Occupational Health and Safety Branch, Ontario Ministry
    of Labor. Toronto, Canada.

 9. Korniewicz, D.M., Laughon, B.E., Butz, E., & Larson, E. Integrity of vinyl and latex procedure
    gloves. Nursing Research 38 (3): 144-146, 1989.

 10. Korniewicz, D.M., Laughon, B.E., Cyr, W.H., Lytle, C.D., & Larson, E. Leakage of virus
     through used vinyl and latex examination gloves. Journal of Clinical Microbiology 28 (4): 787-
     788, 1990.

 11. Korniewicz, D., Kirwin, M., Cresci, K., & Larson, E. Leakage of latex and vinyl exam gloves
     in high and low risk clinical settings. American Industrial Hygiene Association Journal 54 (1):
     22-26, 1993.

 12. Patterson, P. Allergy issues complicate buying decision for gloves. OR Manager, June 1995.
 13. Reis, J. Latex Sensitivity. AORN Journal 59 (3): 615-621, 1994.

 14. "Rubber." Microsoft Encarta, 1993.
 15. "Rubber, natural and synthetic." Compton’s Interactive Encyclopedia, 1994.

 16. Sosovec, D. Hand care protocol. Baxter Healthcare Corporation.

 17. Sussman, G.L. & Beezhold, D.H. Allergy to Latex Rubber. Annals of Internal Medicine, 122
     (1): 43-46, 1995.

 18. Sussman, G.L. & Beezhold, D.H. Safe use of natural rubber latex. Allergy and Asthma
     Proceedings 17 (2): 101-102, 1996.
19. Swanson, M.C., Bubak, M.E., Hunt, L.W., Yunginger, J.W., Warner, M.A., & Reed, C.E.
    Quantification of occupational latex aeroallergens in a medical center. Journal of Allergy and
    Clinical Immunology 94: 445-451, 1994.
20. Truscott, W. The industry perspective on latex. In Fink, J. (ed). Immunology and Allergy
    Clinics of North America 15 (1), 1995.
21. Turjanmaa, K., Laurila, K., Makinen-Kikjunen, S., & Reunala, T. Rubber contact urticaria.
    Contact Dermatitis 19: 362-367, 1988.

				
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