The presence of latex can induce false-positive skin tests in subjects tested with penicillin determinants

Latex allergens are ubiquitous, and exposure may occur from different sources in the medical environment and in daily life. The observation that subjects with latex allergy were skin test positive to major and minor determinants of penicillins led our group to carry out an investigation to try to explain these findings. A group of 20 subjects with a history of allergy to latex and with positive skin tests for, but good tolerance of, penicillins was studied. The presence of latex contaminants was studied by RAST and RAST inhibition. Sixteen of the subjects were positive to at least one of the penicillin determinants used, and 14 (87%) of these were positive to at least two determinants. Repetition of skin tests using the container without a stopper changed the skin test results to negative in almost all cases, indicating that some trace contaminants had still been present. RAST-inhibition studies showed that in all penicillin determinants there were trace amounts of latex allergens varying between 3 and 0.03 micrograms/ml. These results indicate that skin tests with penicillin in subjects allergic to latex may give false-positive results and lead to such patients being falsely diagnosed as allergic to betalactams when penicillins are stored in containers with rubber stoppers.

Anaphylaxis in children: a 5-year experience

OBJECTIVES

To identify the causative agents, presenting signs and symptoms, and course of disease in children diagnosed with anaphylaxis. Design. Five-year retrospective chart review.

SETTING

Urban children's hospital pediatric emergency department, operating suite, and inpatient units.

PARTICIPANTS

Fifty-five cases of anaphylaxis in 50 patients 1 to 19 years of age.

INTERVENTIONS

None.

RESULTS

The most common inciting agents in this population were latex (27%), food (25%), drugs (16%), and venoms (15%). Thirty-two cases (58%) occurred outside of the hospital, including 3 of 11 severe cases. Nineteen (35%) had histories of prior allergy to the causative agent. Most agent exposures were intravenous (38%), oral (27%), or dermal (20%). The most common systems involved were respiratory (93%), skin (93%), cardiovascular (26%), and neurologic (26%). Features distinguishing the 11 patients requiring intensive care included latex agents (45%), nonenteral route of exposure (91%), and presence of cardiovascular symptoms (45%). Of the 17 patients with known past anaphylaxis, only 5 had epinephrine self-administration devices available, and 3 had used them.

CONCLUSIONS

(1) Most patients with anaphylaxis present with skin or respiratory symptoms. (2) Severely ill children more commonly have nonenteral and/or latex exposures that occur in the hospital. (3) Most children with anaphylaxis have no stated histories of prior reaction to the causative agent. (4) Those patients who have had past episodes of anaphylaxis infrequently have epinephrine self-administration devices available for use.

Glove powder--a risk factor for the development of latex allergy?

Studies are described which compare the prevalence of sensitisation against latex proteins in medical personnel in different hospitals. The objective of these studies was to find out whether the use of powdered or unpowdered gloves could be related to the prevalence of latex allergy. Employees of one of the investigated hospitals (Germany) were using only powdered latex gloves, and in the other two hospitals (Great Britain) low protein powder-free latex gloves were used. Methods by which latex allergy can be avoided are suggested.

Cost of latex device-related occupational illness, workmen's compensation and legal issues

In the United States, health care workers who become sensitised to latex face substantial problems. Their careers may prematurely come to an end, leaving them with a long struggle to achieve adequate compensation. This paper outlines some of those problems, and the actions necessary by employers, employees and worker disability groups to prevent future problems.

Setting standards for product selection: allergy prevention

It is axiomatic to state that if products made of natural rubber latex were not used in health care settings then there would be no problems of acquired hypersensitivity from such products. Although synthetic materials are available they do not currently possess the same technical qualities of elasticity and comfort, nor do they deliver the desired degree of protection against biological agents as gloves made out of natural rubber latex. Selection of gloves either for non-sterile procedures or sterile surgical use should be based on this understanding, and gloves with minimal levels of extractable latex proteins should be used.

Perioperative collapse: prevalence of latex allergy in patients sensitive to anaesthetic agents

The evidence in the literature suggests that the prevalence of latex allergy in the general population is approximately 1%. With increasing awareness of transmission of HIV and other infections such as hepatitis B, the use of latex gloves and condoms has escalated in recent years. As cheaper latex gloves of variable and doubtful quality flood the market, health care workers and patients are being increasingly sensitized by these latex products. A retrospective study investigated the prevalence of latex allergy in a cohort of 26 patients who suffered perioperative anaphylactoid reactions. 84% of these patients were hypersensitive to at least 1 anaesthetic-related agent. 7.7% were also allergic to latex (p = 0.028). Atopy is a strong predisposing factor (p = 0.006). An accurate preoperative history of atopy and past reactions to latex will identify most at-risk patients. Prick test and RAST to latex will confirm the latex allergy. Anaesthetists, surgeons, allergists and other health practitioners should be aware of this problem.

Cost implications of allergy and recent Canadian research findings

The cost to hospital's managing latex allergy problems, and of instituting a co-operative response to the problem is estimated, and compared with the estimated cost of ignoring the problem. The costs and benefits of the interventional strategies, i.e. complete elimination of powdered latex gloves in favour of powder free latex gloves, are described in detail. It is demonstrated that the chosen interventional strategy not only reduced overall costs, but surprisingly, also reduced glove purchase costs.

Allergenic proteins in different brands of latex and synthetic medical examination gloves

The steady increase in anaphylactic reactions to latex medical gloves has raised increasing awareness in the medical community. Even gloves claimed to be hypo-allergenic still may contain substantial amounts of IgE-binding proteins. We have studied non-powdered latex and synthetic examination glove extracts for their allergenicity using the immunoblot technique. Protein levels varied considerably among glove extracts and the amount did not always correlate with the presence of allergenic proteins. IgE binding proteins were found in 2 of the 7 powder-free latex glove brands. Synthetic glove extracts did not contain allergens. The study demonstrates that immunoblot analysis is a useful technique in order to select gloves with a minimal risk to raise IgE antibodies.

Type I allergies to latex and the aeroallergenic problem

Between 1989 and 1995, a 12-fold increase in latex allergy was documented amongst our patients. Similar findings have been noted elsewhere. Increase in type I allergies to latex has become an international problem. The issues associated with latex allergy are described, including those posed by the ubiquitous nature of latex in medical equipment, and in commonplace domestic objects. The potential for allergic patients to cross react to a variety of fruits or plants is an added problem for sensitized patients. This paper concludes that the universal introduction of powder-free surgical gloves with low protein content would be a very important measure in the prevention of acquired latex allergy.

Surgical glove hazards: a commentary

Surgical contaminants of many kinds, including glove powder, cause granuloma formation. This is particularly well documented in the peritoneal cavity, but has been demonstrated in most anatomic sites. In addition, systemic manifestations result from the absorption of the latex protein antigens onto the starch powder on the surgical gloves, which is aerosolized when the gloves are donned or removed.

Endotoxin and particulate matter on surgical gloves

Because of the continual need to protect of health care workers, gloves are increasingly used. Most gloves purchased are powdered. Besides having deleterious effects on wound healing, glove powder can act as a vehicle for latex allergens, endotoxin, and possibly bacteria. Few tested gloves had undetectable levels of endotoxin, and only one was free from particulate matter. Since powder particles can become airborne and are thus easily spread, concerns for health care professionals and patients arise. To reduce risks for exposure, glove-selection criteria must include low or undetectable levels of latex allergens, endotoxin, and particulate matter.

New developments in latex allergy

There are several new developments in studies of latex allergy. It appears that many of the allergens to latex are defense proteins that the plant uses to respond to pathogens. Rubber elongation factor, hevein preprotein, hevamine, patatin, and glucanase have been identified as allergic proteins. In addition, processing and leaching of natural rubber latex devices results in a very low allergen content. Powdered rubber gloves appear to be a major contributor to airborne latex allergens. The replacement of low allergen-containing latex gloves for high allergen-containing gloves markedly reduces the levels of latex allergens in the clinical setting. By decreasing the inhalation and contact with latex allergens, we would expect a reduction in latex sensitization in the hospital.

Latex anaphylaxis in a myasthenic child undergoing thymectomy

Anaphylactic shock occurred in a 9-year-old myasthenic boy after induction of anesthesia for thymectomy. Resuscitation was successful. Subsequent skin testing identified latex as the cause. Although the patient was not in a high-risk group for latex allergy, detailed questioning confirmed that sensitivity had developed during repeated exposures in previous anesthesia and dental care. Six months later, after taking steroids and antihistaminic drugs prophylactically and avoiding all latex-containing products, the boy underwent uncomplicated thymectomy. The possibility of latex allergy should be borne in mind when dealing with patients previously exposed to repeated medical care. Adequate, latex-free equipment should be available in operating rooms to deal with patients who are allergic to latex.

Occupational asthma due to latex in health care workers

Immediate hypersensitivity reactions ranging from mild urticaria to life threatening anaphylaxis after exposure to natural rubber latex have been reported frequently in health care workers while occupational asthma due to latex exposure is less well studied. The results of specific challenge tests and immunological tests in four health care workers with work related respiratory and skin disorders induced by the use of latex gloves are described. Occupational asthma was confirmed in three subjects by specific challenge tests. All had a positive skin test reaction to the latex extract; specific IgE antibodies were detected in only one subject. The fourth subject had a negative specific inhalation and skin test reaction to the latex extract. Peak expiratory flow monitoring at work and away from work showed a pattern consistent with work related asthma. These findings confirm that latex is a cause of occupational asthma in health care workers.

A nurse with anaphylaxis to stone fruits and latex sensitivity: potential diagnostic difficulties to consider

BACKGROUND

There have been several recent reports describing a cross-reactivity between latex and antigens derived from a number of fruits, including those of the stone fruit family. The relationships between the allergic reactions to the antigens from these plant products are still being defined.

OBJECTIVE

To characterize the IgE reactivity of a patient who had anaphylactic reactions following the ingestion of several members of the stone fruit family (ie, plum, peach, and nectarine) and had a positive clinical history for latex allergy.

METHODS

The patient's serum was tested for the presence of specific IgE for latex, stone fruits, and a panel of other foods reported to be cross-reactive with latex. Prick testing was also performed with freshly prepared extracts from the implicated fruits. Finally, the immunochemical relationship between this patient's fruit and latex sensitivity was investigated by RAST inhibition.

RESULTS

The patient had strongly positive skin tests to the freshly prepared fruit extracts but the in vitro food-specific IgE tests were equivocal or very low positive. In vitro latex-specific IgE tests were strongly positive. The stone fruit extracts were shown to be inhibitors of the patient's latex specific IgE by RAST inhibition.

CONCLUSION

Skin testing with freshly prepared fruit extracts was more sensitive than the in vitro tests with this patient. The inhibition data support an immunochemical relationship between the patient's latex allergy and sensitivity to stone fruits.