The occurrence of allergy to natural rubber latex is a singular event in the annals of medicine. Because of unique advantages in flexibility, strength, elasticity and barrier properties, latex gloves have been widely used in medicine since the turn of the century. Latex is also a common component of many other medical devices, including drains, catheters and wraps, and it is an ingredient in adhesives used for dressings and tapes. While allergic contact dermatitis due to sensitization to rubber chemical additives has been appreciated for over 40 years, rubber latex itself was long considered immunologically inert.
The abrupt transformation of latex into a potent antigenic protein has been a source of considerable consternation and doubt. However, the broad scope of this problem is documented and beyond contradiction. In children with spina bifida or other conditions who undergo early, frequent instrumentation, latex allergy has reached epidemic levels. Studies of exposed health care workers from several different countries are remarkably consistent in finding between 8 and 17 percent who are at risk for allergic reactions.1 The frequency of reports of severe and anaphylactic reactions occurring during skin testing, during medical procedures and with inadvertent contact outside of the medical setting all suggest an unusual propensity of this antigen to evoke potentially catastrophic responses. Management of latex allergy presents additional challenges. Traditional instructions given to patients for avoiding discretely encountered allergens (such as penicillin) appear less effective when applied to latex, given the ubiquitous nature of latex products. Patients with latex allergy are also prone to food allergies in a wide range of cross-reactive tropical fruits, nuts and vegetables, and the onset may be heralded by an anaphylactic event.2
As the article by Reddy in this issue of American Family Physician amply attests, physicians not only care for latex-allergic patients but also are members of a high-risk group themselves.3 Occupational latex exposure, particularly from powdered latex gloves, constitutes a major risk factor for latex allergy. Initial reactions of contact urticaria progress to asthma and anaphylaxis with troubling frequency.4 Recent findings indicate that nearly one half of latex-allergic health care workers undergoing a challenge test with latex gloves show evidence of an asthmatic reaction despite no previous history of occupational asthma; these findings underscore the importance of controlling exposure in the medical setting.5
In the absence of a high index of suspicion, the diagnosis can easily be missed. It is not unusual for patients to dismiss early manifestations of latex allergy as unimportant, particularly if the trigger is not easily recognized. Young women may be too embarrassed to report allergic reactions to condoms or to diaphragm contraceptives unless directly questioned. Health care workers may not perceive the importance of changes in their reactions to latex gloves or may conceal symptoms for fear of jeopardizing their jobs. Physicians too may “mis-attribute” latex-induced symptoms to drug reactions or “mis-perceive” hysteria or malingering in patients with early latex-induced asthma. Careful appraisal is warranted of any report of reactions to latex gloves or of other latex products, of food allergies that progress to include tropical fruits or vegetables, or of any previous anaphylactic attack.
The central precept of latex allergy treatment is avoidance. Unfortunately, the lack of content labeling of medical devices makes determining which are safe a daunting task.6 Moreover, quantities of latex proteins carried by glove-donning powder are sufficient to generate aero-allergen levels capable of triggering allergic reactions and promoting atopic sensitization even in the absence of direct contact.7 Substitution of non-powdered low-allergen gloves results in a dramatic reduction in latex aerosols, indicating that powdered gloves are the primary source of latex aero-allergen.8
For this reason, the American College of Allergy, Asthma, and Immunology and the American Academy of Allergy, Asthma, and Immunology have recently issued a joint statement calling for an end to the use of powdered latex gloves. Although cost considerations are frequently cited as an objection to converting to low-allergen gloves, a recent report from the Mayo Clinic9 documented substantial savings after such a conversion.
For those who are already allergic to natural latex rubber, treatment with antihistamines should not be considered a safe alternative to avoidance and, in fact, use of antihistamines may delay detection of acute reactions. Early initiation of anti-asthmatic therapy, particularly inhaled corticosteroids, is encouraged, but affected workers should return to work only after all workers in their geographic area or work unit are using non-latex or non-powdered gloves. Family physicians are well advised to adopt office policies offering this same measure of safety both for patients and for health care workers.