Latex allergy. A position paper of the British Society of Allergy and Clinical Immunology

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.

The role of allergen components for the diagnosis of latex-induced occupational asthma

BACKGROUND

Recombinant Hevea brasiliensis (rHev b) natural rubber latex (NRL) allergen components have been developed to assess the patients' allergen sensitization profile and to improve the diagnosis of NRL allergy.

OBJECTIVE

To examine whether the determination of specific IgE (sIgE) reactivity to a panel of recombinant allergen components would be helpful for diagnosing NRL-induced occupational asthma (OA) in predicting the outcome of a specific inhalation test.

METHODS

sIgE levels to NRL extract and 12 recombinant NRL allergen components were assessed in 82 subjects with OA ascertained by a positive specific inhalation challenge (SIC) with NRL gloves and in 25 symptomatic subjects with a negative challenge.

RESULTS

The sensitivity, specificity, positive predictive value, and negative predictive value of a NRL-sIgE level ≥0.35 kUA /l as compared to the result of SICs were 94%, 48%, 86%, and 71%, respectively. The positive predictive value increased above 95% when increasing the cutoff value to 5.41 kUA /l. Subjects with a positive SIC showed a significantly higher rate of sIgE reactivity to rHev b 5, 6.01, 6.02, and 11 than those with a negative SIC. A sIgE sum score against rHev b 5 plus 6.01/6.02 ≥ 1.46 kUA /l provided a positive predictive value >95% with a higher sensitivity (79%) and diagnostic efficiency (Youden index: 0.67) as compared with a NRL-sIgE ≥5.41 kUA /l (49% and 0.41, respectively).

CONCLUSION

In suspected OA, high levels of sIgE against rHev b 5 combined with rHev b 6.01 or 6.02 are the most efficient predictors of a bronchial response to NRL.

Identification and practical management of latex allergy in occupational settings

Allergy to natural rubber latex (NRL) from Hevea brasiliensis is a relevant occupational health hazard. The use of gloves and products manufactured with latex and environmental allergen exposure in the work environment are risks factors for the development of occupational allergy among different job categories. Healthcare workers have been the most commonly affected, but other professions with exposure to latex products such as hairdressers, cleaners, food handlers and those making natural rubber latex (NRL) products are also at risk of developing occupational allergy. Clinical manifestations of IgE-mediated latex allergy can range from troublesome skin disorders to life-threatening systemic reactions. It is very important to identify the occupational allergic diseases in their early stages in order to implement avoidance strategies. For this purpose, the interventions for prevention should emphasize the importance of latex allergy awareness and surveillance among exposed workforces.

Natural rubber latex allergy: implications for the orthodontist

Natural rubber latex (NRL) allergy can have potentially serious consequences, and reports of orthodontic patients reacting to NRL have increased significantly over recent years. It is therefore important for the orthodontist to know how to manage patients with an NRL allergy and how to deal with possible reactions to NRL. Safe and effective practice depends on recognizing patients who are at risk of NRL allergy, and an awareness of materials and equipment that contain NRL and the availability of suitable NRL-free alternatives.

Diagnostic value of the ISAC(®) allergy chip in detecting latex sensitizations

PURPOSE

Latex allergy can be diagnosed by different test methods such as IgE quantification, Western blot, cellular antigen stimulation test (CAST), and in vivo methods [e.g. skin prick test (SPT)]. Phadia provides two modern methods using recombinant latex allergens: ImmunoCAP(®) and the Immuno Solid-phase Allergen Chip (ISAC(®)), which enables simultaneous determination of specific IgE against five latex allergens. We compared the diagnostic sensitivity of the ISAC(®) test kit and the conventional Hev b 5-spiked ImmunoCAP(®) latex extract.

METHODS

Forty sera were sampled from subjects with suspected natural rubber latex (NRL) allergy. These patients had positive SPT to NRL extract, positive NRL Western blots, and positive results in the CAST. All sera were analysed using the ISAC(®) and recombinant NRL ImmunoCAP(®) allergens and compared to the results of 20 negative control sera.

RESULTS

Only 22 of the 40 subjects (55 %) showed positivity to at least one latex allergen on the ISAC(®) (sensitivity ISAC(®) 55 %). The sensitivity of the ImmunoCAP(®) latex extract was 70 %. The most frequently detected sensitization was against Hev b 6.01 (n = 12). When the serum samples were tested with all recombinant ImmunoCAP(®) allergens, three additional sensitizations against latex could be detected compared to the ISAC(®).

CONCLUSIONS

Microarrays do offer many potential benefits such as elegant simultaneous determination of sensitizations against different NRL allergens with minimal amounts of serum. However, a negative NRL test result should be regarded with caution and at least be confirmed by other in vitro methods.

Experiences from occupational exposure limits set on aerosols containing allergenic proteins

Occupational exposure limits (OELs) together with determined airborne exposures are used in risk assessment based managements of occupational exposures to prevent occupational diseases. In most countries, OELs have only been set for few protein-containing aerosols causing IgE-mediated allergies. They comprise aerosols of flour dust, grain dust, wood dust, natural rubber latex, and the subtilisins, which are proteolytic enzymes. These aerosols show dose-dependent effects and levels have been established, where nearly all workers may be exposed without adverse health effects, which are required for setting OELs. Our aim is to analyse prerequisites for setting OELs for the allergenic protein-containing aerosols. Opposite to the key effect of toxicological reactions, two thresholds, one for the sensitization phase and one for elicitation of IgE-mediated symptoms in sensitized individuals, are used in the OEL settings. For example, this was the case for flour dust, where OELs were based on dust levels due to linearity between flour dust and its allergen levels. The critical effects for flour and grain dust OELs were different, which indicates that conclusion by analogy (read-across) must be scientifically well founded. Except for subtilisins, no OEL have been set for other industrial enzymes, where many of which are high volume chemicals. For several of these, OELs have been proposed in the scientific literature during the last two decades. It is apparent that the scientific methodology is available for setting OELs for proteins and protein-containing aerosols where the critical effect is IgE sensitization and IgE-mediated airway diseases.

Primary prevention of latex allergy in healthcare-spectrum of strategies including the European glove standardization

IgE-mediated allergy to natural rubber latex was first noted from rubber gloves in 1979. The initial reports in dermatological journals described contact urticarial reactions; later, severe generalized allergic reactions and asthma were documented. A considerable proportion of the people involved in medical and dental care were found to be sensitized to latex. This article describes and surveys a broad range of primary prevention measures at the local and national levels. Examples are given from paediatrics, dental education, and medical care. National strategies and position papers on latex allergy are presented in which medical professionals, manufacturers and public authorities have cooperated. Special reference is paid to the European work to standardize medical gloves, which led to document EN 455:3.

Latex medical gloves: time for a reappraisal

Many hospitals have implemented policies to restrict or ban the use of devices made of natural rubber latex (NRL) in healthcare as precautionary measures against the perceived risk of NRL allergy. Changes in glove technology, progress in measuring the specific allergenic potential of gloves and a dramatic decrease in the prevalence of NRL allergies after interventions and education prompted us to revisit the basis for justifiable glove selection policies. The published Anglophone literature from 1990 to 2010 was reviewed for original articles and reviews dealing with the barrier and performance properties of NRL and synthetic gloves and the role of glove powder. The review shows that NRL medical gloves, when compared with synthetic gloves, tend to be stronger, more flexible and better accepted by clinicians. The introduction of powder-free gloves has been associated with reductions in protein content and associated allergies. Recently, new methods to quantify clinically relevant NRL allergens have enabled the identification of gloves with low allergenic potential. The use of low-protein, low-allergenic, powder-free gloves is associated with a significant decrease in the prevalence of type I allergic reactions to NRL among healthcare workers. Given the excellent barrier properties and operating characteristics, dramatically reduced incidences of allergic reactions, availability of specific tests for selection of low-allergen gloves, competitive costs and low environmental impact, the use of NRL gloves within the hospital environment warrants reappraisal.

Latex sensitization and allergy in children with spina bifida in Turkey

PURPOSE

The latex allergy is known as a very frequent problem of children with spina bifida (SB). The aim of this prospective study is to determine the frequency of latex sensitization and allergy in Turkish children with SB and to evaluate the related risk factors.

METHODS

We enrolled a total of 175 children and collected them in four groups of patients: children with SB, children who had neurosurgical disorders other than SB, atopic children with allergic diseases, and healthy children as control group. All cases were evaluated for latex sensitivity and allergy with skin prick tests and specific IgE. The diagnosis of latex allergy was confirmed with the latex provocation test.

RESULTS

Ten children with SB, two children with other neurological disorders, and three atopic children with allergic disease were found "sensitized to latex". Among these sensitized children, only one child with SB had latex allergy. Multivariate logistic regression analysis of the children with SB and other neurologic disorders and the whole group of patients showed that skin test positivity, the presence of noncentral nervous system (CNS) surgery, and the number of the operations were significant risk factors for latex sensitization.

CONCLUSIONS

Our study showed that rates of latex sensitivity and allergy in children with SB in Turkey are significantly lower than published rates in literature. We also found that atopy, the presence of non-CNS operations in children with SB and other neurologic disorder, and total number of operations in the whole group of patients are the most important risk factors for latex sensitization.

Latex allergy and filaggrin null mutations

OBJECTIVES

Natural rubber latex (NRL) contains over 200 proteins of which 13 have been identified as allergens and the cause of type I latex allergy. Health care workers share a high occupational risk for developing latex allergy. Filaggrin null mutations increase the risk of type I sensitizations to aeroallergens and it is possible that filaggrin null mutations also increase the risk of latex allergy. The aim of this paper was to examine the association between filaggrin null mutations and type I latex allergy.

METHODS

Twenty latex allergic and 24 non-latex allergic dentists and dental assistants, occupationally exposed to latex, were genotyped for filaggrin null mutations R501X and 2282del4. Latex allergy was determined by a positive reaction or a historical positive reaction to a skin prick test with NRL.

RESULTS

41 individuals were successfully genotyped. Three individuals were filaggrin mutation carriers. One (2.4%) was a 2282del4 heterozygote and two (4.9%) were R501X heterozygote. No homozygote or compound heterozygote carriers were detected. No association between filaggrin null mutations and type I latex allergy was found (p=0.24). Patients with type I latex allergy more often reported contact dermatitis.

CONCLUSIONS

This is the first study to examine a highly plausible association between filaggrin null mutations and type I latex allergy. The study subjects were occupationally exposed to latex but no association between latex allergy and filaggrin mutations were detected. Sensitization to latex in the cases in this study may not have occurred through direct skin contact but through the respiratory organs via latex proteins that are absorbed in glove powder and aerosolized.

Latex sublingual immunotherapy: can its safety be predicted?

BACKGROUND

Complete avoidance sometimes cannot be possible in latex-allergic health care workers. So far, very few double-blind placebo-controlled studies revealed the efficacy of sublingual latex immunotherapy (SLIT) in those patients.

OBJECTIVE

Our aim was to evaluate the efficacy and safety of latex SLIT in health care workers.

METHODS

30 patients (all health care workers) diagnosed as latex allergic were advised to avoid latex exposure and were given information about the prevention measures and asked to return two months later. 24 patients who were still symptomatic despite prevention measures were informed about the latex SLIT study and asked to participate. However, only 12 gave approval and were randomized to receive sublingual latex extract or placebo. Symptom scores and latex cutaneous provocation test scores were recorded at baseline and at the 6th and 12th months of the study.

RESULTS

Two patients experienced anaphylaxis, 1 patient showed severe bronchial obstruction during dose incremental phase and were excluded from the study. The differences of the symptom and provocation scores between baseline and the 12th month of the treatment were significant in the active group (p = .042, p = .038, respectively). Also the symptom and provocation scores at 12 months were significantly lower in the active group than in the placebo group (p = .035, p = .013, respectively).

CONCLUSION

Latex SLIT can be used as an effective treatment for latex-allergic health care patients having difficulties in applying adequate avoidance measures. However, the risk of systemic reactions should be kept in mind and sufficient precaution measures must be made available.

Latex-induced occupational asthma: time trend in incidence and relationship with hospital glove policies

BACKGROUND

Natural rubber latex (NRL) has become as a major cause of occupational asthma (OA) in workers using NRL gloves. Few population-based studies have assessed the impact of changes in the patterns of glove usage on the incidence of NRL-induced OA.

OBJECTIVE

To characterize the time trends in incident cases of NRL-induced OA in Belgium and examine whether incidence rates were related to the types of gloves used in hospitals.

METHODS

Incident cases of NRL-induced OA were identified through a retrospective review of all claims submitted to the Workers' Compensation Board up to December 2004. Based on the results of diagnostic procedures, the diagnosis of NRL-induced OA was categorized as definite, probable, unlikely, or indeterminate. The patterns of glove usage were characterized through a questionnaire survey of Belgian hospitals.

RESULTS

A total of 298 claims for NRL-induced OA were identified, including 127 subjects with definite OA and 68 with probable OA. Categorized by the year of asthma onset, the incident cases of definite and probable NRL-induced OA markedly decreased from 1999 onwards. The use of powdered NRL gloves fell from 80.9% in 1989 to 17.9% in 2004. Powdered NRL gloves were predominantly substituted with NRL-free gloves, especially in the case of non-sterile procedures.

CONCLUSION

These national compensation-based data confirm that a persistent decline in the incidence of NRL-induced OA has occurred since late 1990s. This downward trend has temporally been associated with a decreasing usage of powdered NRL, further supporting a beneficial role of changes in glove policies.

[Hygiene in endovaginal gynecologic and obstetrical ultrasound in 2008]

Hygiene of ultrasound probes is a hot topic in obstetric and gynecologic ultrasound. The issue concerns mainly the risk of contamination and the need for specific procedures to ensure a high degree of protection against infectious diseases, even if a disposable barrier cover is used. As there are no referenced quality criteria for these disposable probe covers, it is crucial to verify that they are CE marked. The use of condoms as probe covers is not recommended even though they present a lower rate of disruption compared to commercial probe covers. The global rate of probe cover perforation is of 1 to 9%. To date, there are no case reports of contamination by ultrasound examination, be it vaginal or abdominal. Nevertheless, every patient must be regarded as a potential source of infection. The French recommendations consider endovaginal ultrasound probes as semi-critical instruments and thus require intermediate-level disinfection. Because of the risk of disruption, American as well as Canadian and Australian recommendations insist on high-level disinfection of the probe. Every operator should follow reasonable hygiene rules and appropriate precautions should be taken in order to reassure the patients about the risks of contamination during any ultrasound examination.

Food allergy in adults: an over- or underrated problem?

BACKGROUND

10% to 20% of the population sees itself as suffering from food allergy, yet genuine, immune-mediated food allergy is suspected by patients and their physicians far more often than it is actually shown to be present. The unfounded suspicion of an IgE-mediated food allergy can substantially impair a patient's quality of life through needless dietary restriction and the accompanying anxiety. On the other hand, an IgE-mediated food allergy that has gone undiagnosed or that has not been taken seriously can manifest suddenly with anaphylaxis, which may be life-threatening. The present study, carried out on a large cohort of patients, underscores the importance of differentiating IgE-mediated food allergy from other, nonallergic types of food reaction.

METHODS

419 patients that had been referred to our outpatient allergy clinic for suspected food allergies underwent a standardized allergological diagnostic evaluation, including thorough allergologic history-taking, IgE serology, and challenge tests when indicated.

RESULTS

214 patients (51.1%) were found to have an IgE-mediated food allergy. Almost half of these patients (24.3% of the overall group) had previously experienced food-induced anaphylaxis. In 205 patients (48.9%), however, an IgE-mediated food allergy was ruled out as far as possible.

CONCLUSION

Only a comprehensive allergological evaluation performed by an experienced allergologist in accordance with current guidelines can protect patients from the negative consequences of excessive concern about a nonexistent food allergy (e.g., needless dietary restriction) or, on the other hand, the negative consequences of inadequate attention to a genuine food allergy (anaphylaxis). A proper evaluation consists of detailed allergologic history-taking, skin tests, and challenge tests when indicated.

Latex allergy: two educational cases

Natural rubber latex (NRL) allergy is a significant problem both for health care workers and for children with complex medical and surgical conditions that require multiple surgical interventions. Primary and secondary prophylaxis are effective measures in identified high risk groups, such as spina bifida (SB). It is therefore likely that with proper attention to prevention and secondary prophylaxis in the highest risk groups that the numbers of paediatric SB patients with NRL allergy will continue to decrease. In contrast medical awareness of established latex allergy needs to be maintained. The issue of latex sensitisation via fruit and food allergy will also remain, so some of the attention that SB patients have received in the past may need to be refocussed onto other emerging high risk groups. Innovative immunomodulatory approaches may soon translate to the clinic for latex sensitised or allergic subjects.

The prevalence of latex allergy in sixth-year medical students: assessment of knowledge, risk, and attitudes about future specialty direction

BACKGROUND

In the prevention of latex allergy, knowledge levels and risk determination for latex allergy of medical students gain importance.

OBJECTIVES

To evaluate the latex allergy knowledge levels of sixth-year medical students and their latex allergy risk.

METHODS

Students completed a questionnaire that assessed basic knowledge of latex allergy and that evaluated latex-related symptoms and latex exposure. The specialty branch students were going to choose in the Medical Specialty Examination was also asked. Skin prick tests (SPTs) with latex and inhalant allergens and patch tests with latex-related products were then performed. Finally, students were asked again about any changes in branch selection after learning their individual risks.

RESULTS

Two hundred twenty sixth-year students were enrolled. Forty-four percent of the students gave the right answer for description of latex. Correct identification of at least 1 latex-related product used outside and inside hospitals was 55.5% and 95.5%, respectively. The prevalence of latex sensitization was 4.4% according to SPT results. The positivity of SPT to any inhalant allergen was 35% (n = 64). None of the students changed their mind about their specialty branch after learning their latex allergy risk.

CONCLUSIONS

Last-year medical students have a remarkably low latex allergy knowledge level, which imposes a serious professional risk. Training strategies based on the benefit to this risk group and reevaluation are strongly recommended before graduation from medical school.

Latex allergy: a model for therapy

Allergy to natural rubber latex products emerged as an important clinical condition following an increase in the use of latex gloves for barrier protection in the early 1980s. In addition to latex glove users, other high-risk groups with different latex exposure include spina bifida patients and others with multiple surgical procedures. Subjects with fruit and vegetable allergy are also at risk due to cross-reactive allergens. Following the significant advances in the identification and characterization of common aeroallergens, latex allergy was well placed to become an excellent model of therapy. Awareness of latex allergy and modes of sensitization enabled epidemiological studies to inform allergen avoidance initiatives, substantially reducing inadvertent exposure in major hospitals in Western countries. Spina bifida is often identified in utero or soon after birth, allowing vigorous latex allergen avoidance with enhanced efficacy of primary prevention. However, changing demographics of latex allergy and technological revolution in countries such as China and India are predicted to unleash a second wave of latex allergy reemphasizing the incentive for improved manufacturing procedures for latex products. The desirable high tensile strength and elasticity of natural rubber latex have made the commercial identification of good alternatives very difficult but this would also be attractive for primary prevention. In addition, an effective specific immunotherapy regimen would be valuable for selected high-risk atopic individuals. Current subcutaneous and sublingual immunotherapy schedules have been tested for treatment of latex allergy with evidence of efficacy but the risks of adverse events are high. For such potent allergens as latex, hypoallergenic but T cell-reactive preparations are required for clinical use. Identification of allergenic components of latex products, with generation of monoclonal antibodies and recombinant allergens, allowed sequence determination and mapping of T cell and B cell epitopes. Together, these reagents and data facilitated improved diagnostics and investigation of novel-specific therapeutics. Potential hypoallergenic latex preparations identified include modified non-IgE-reactive allergen molecules and short T cell epitope peptides. The co-administration of adjunct therapies such as anti-IgE or corticosteroids and of appropriate adjuvants for induction of regulatory T cell response offers promise for clinically effective, safe latex-specific vaccines.

Sensitivity and specificity of different skin prick tests with latex extracts in pediatric patients with suspected natural rubber latex allergy--a cohort study

Skin prick tests (SPT) with latex extracts are commonly used in the diagnostic approach of natural rubber latex (NRL) allergy. Non-ammoniated latex extracts are commonly utilized for this purpose. There is only one commercially available ammoniated latex extract for both diagnostic and therapeutic purposes. To our knowledge, no direct clinical comparisons have been made so far comparing sensitivity and specificity of different latex extracts in patients with clinically confirmed latex allergy. The objective of this study was to evaluate sensitivity and specificity of non-ammoniated or ammoniated SPT of latex extracts in children with a clinical history suggestive of NRL allergy. Forty-two subjects (age 4-15 yr), referred to our Allergy Clinic Center, with suspected clinical signs of NRL allergy were evaluated. Patients were selected according to the following inclusion criteria: pediatric patients of age above 4 yr with a suspected clinical history of urticaria, rhinoconjunctivitis and/or asthma due to sensitization to NRL. A definitive NRL allergy diagnosis was made on the identification of latex-specific IgE (>0.7 kU/l), positive glove use test and a highly indicative clinical history. NRL allergy was confirmed in 26 (62%) subjects. SPT for latex were performed with three different SPT solutions containing non-ammoniated NRL extracts (product A: Lofarma SpA, Milan, Italy and product B: Stallergenes, Milan, Italy) or an ammoniated extract (product C: ALK-Abellò, Madrid, Spain). A positive result was considered as the appearance of a wheal with a diameter >3 mm. In patients with confirmed NRL allergy, wheal mean (s.d.) diameters were 7.3 (2.1) with product C, and 5.7 (2.3) and 4.4 (1.8) with products B and A respectively (p = 0.004 C vs. B and A). Mean wheal diameters were significantly higher for product C in comparison with product B and A (p < 0.04). Sensitivity according to the different products tested was 65% (product A); 81% (product B) and 96% (product C) (p = 0.0084; C vs. A). No difference between the three products was observed regarding diagnostic specificity (94%, 88% and 94%, product A, B and C, respectively). Our study shows that diagnostic sensitivity of different latex extract for SPT could differ. In this particular clinical setting (i.e., children with NRL allergy) ammoniated latex extract shows a higher sensitivity in comparison with non-ammoniated products. This aspect should be considered in the diagnostic approach in subjects with suspected NRL allergy. In children with clinical confirmed latex allergy, sensitivity and specificity of different commercially available skin prick test could vary. Ammoniated latex extract has shown a higher sensibility in comparison with non-ammoniated products.

The management of anaphylaxis in childhood: position paper of the European academy of allergology and clinical immunology

Anaphylaxis is a growing paediatric clinical emergency that is difficult to diagnose because a consensus definition was lacking until recently. Many European countries have no specific guidelines for anaphylaxis. This position paper prepared by the EAACI Taskforce on Anaphylaxis in Children aims to provide practical guidelines for managing anaphylaxis in childhood based on the limited evidence available. Intramuscular adrenaline is the acknowledged first-line therapy for anaphylaxis, in hospital and in the community, and should be given as soon as the condition is recognized. Additional therapies such as volume support, nebulized bronchodilators, antihistamines or corticosteroids are supplementary to adrenaline. There are no absolute contraindications to administering adrenaline in children. Allergy assessment is mandatory in all children with a history of anaphylaxis because it is essential to identify and avoid the allergen to prevent its recurrence. A tailored anaphylaxis management plan is needed, based on an individual risk assessment, which is influenced by the child's previous allergic reactions, other medical conditions and social circumstances. Collaborative partnerships should be established, involving school staff, healthcare professionals and patients' organizations. Absolute indications for prescribing self-injectable adrenaline are prior cardiorespiratory reactions, exercise-induced anaphylaxis, idiopathic anaphylaxis and persistent asthma with food allergy. Relative indications include peanut or tree nut allergy, reactions to small quantities of a given food, food allergy in teenagers and living far away from a medical facility. The creation of national and European databases is expected to generate better-quality data and help develop a stepwise approach for a better management of paediatric anaphylaxis.

Food allergy in children

Food allergy is being increasingly recognised with the highest prevalence being in preschool children. Pathogenesis varies so diagnosis rests on careful history and clinical examination, appropriate use of skin prick and serum-specific IgE testing, food challenge, and supervised elimination diets. A double blind placebo controlled food challenge is the gold standard diagnostic test. Avoidance of the allergenic food is the key towards successful management. IgE mediated food allergy may present as a potentially fatal anaphylactic reaction, and management consists of the appropriate use of adrenaline (epinephrine) and supportive measures. Sensitisation remains a key target for intervention. Disease modifying agents are currently under trial for managing difficult allergies. Management requires a multidisciplinary approach and follow up.

Pseudo-Latex Allergy Associated With ???Latex??? Paint Exposure: A Potential Cause of Iatrogenic Disability

OBJECTIVE

We sought to describe outcomes for three health care workers with natural rubber latex (NRL) allergy reporting illness after exposure to latex paint.

METHODS

We undertook a retrospective review of medical and occupational histories, diagnostic, treatment, and work recommendations. Outcomes included lost time, workers compensation indemnity costs, and return to work.

RESULTS

None of the paints contained NRL. Cases 1 and 2 initially were misdiagnosed as suffering allergic reactions to NRL, resulting in 7 and 23 months lost time, $15,790 and $139,000 indemnity costs, respectively, and both failing to return to work. Case 3 was correctly diagnosed as not exposed to NRL, with only several lost days, no indemnity costs, and continued to work.

CONCLUSIONS

The failure to recognize that synthetic paints do not contain NRL can lead to misdiagnosis, inappropriate exposure, and work avoidance recommendations and iatrogenic disability.

Alergia al látex

OBJECTIVE

To review the etiology, diagnosis, prevention and treatment of latex allergy in the hospital setting, and to establish a list of potentially hazardous drugs.

METHOD

A literature search was performed. A guide about latex-containing drugs (any component) was developed by contacting manufacturers.

RESULTS

The most relevant factor for latex sensitization is exposure extent. Regarding diagnosis the medical history and skin testing are crucial; regarding secondary prevention, identifying the various at-risk groups. Immunotherapy is currently considered a valid option for the management of this condition.

CONCLUSIONS

The development of a guide listing latex-containing drugs is essential for the primary prevention of allergic reactions to this substance in hospital.

IgE-mediated sensitisation, rhinitis and asthma from occupational exposures. Smoking as a model for airborne adjuvants?

OBJECTIVE

Airborne pollutants with adjuvant effect, called airborne adjuvants, may promote IgE-sensitisation and development of allergic airway diseases. Smoking and occupational allergen exposures were reviewed to establish a general and verified framework for hazard identification and risk assessment of adjuvant effects of airborne pollutions.

METHODS

The relative risks and the attributable risks of adjuvant effect of smoking were determined for co-exposures with green coffee and castor beans, ispaghula, senna, psyllium, flour and grain dust, latex, laboratory animals, seafood, enzymes, platinum salts, organic anhydrides, or reactive dyes.

RESULTS

Adjuvant effects of smoking depended on the types of allergen, but not on whether sensitisation or allergy was promoted by atopy-the hereditarily increased ability to increase IgE formation.

CONCLUSION

Promotion of IgE sensitisation in humans and in animals may serve for hazard identification of adjuvant effects. Risk assessment has been based mainly on epidemiological studies, which are sensitive to confounding factors. This highlights the need to develop appropriate animal models for risk assessment.

Prevalence of latex allergy in the community at age 7 years

BACKGROUND

Latex allergy has been highlighted as a problem in children during the last decade based on a number of case series of children with particular problems such as spina bifida. The actual prevalence of latex allergy in the general United Kingdom population is unclear.

OBJECTIVE

To estimate the prevalence of childhood latex allergy in the general population.

METHODS

The Avon Longitudinal Study of Parents and Children is a geographically based cohort that has been prospectively followed since birth. The children were invited for skin prick testing at 7 years of age.

RESULTS

Four subjects out of 1877 tested were sensitized to latex. None had a history of clinical reactions to latex.

CONCLUSION

This study suggests that the prevalence of latex sensitization and clinical latex allergy in the general childhood population are very low, 0.2% (95% confidence interval 0.1-0.6%) and 0.0% (0-0.2%), respectively.

Investigative methods for natural rubber latex allergy in the UK

Allergy to natural rubber latex (NRL) has become an important health issue in recent years, but little is known about how this condition is investigated by physicians in the UK. This postal questionnaire of British dermatology and allergy specialists shows substantial variation in diagnostic practice, most notably with regard to the utilization and choice of starting dose of commercial latex prick test dilutions, reliance on allergen-specific immunoglobulin E measurement, investigation of associated fruit allergy and provision of resuscitation equipment/method of consent when challenge testing. 17% of responding physicians who investigate for NRL allergy do not perform prick test or glove challenge because of the potential risk of anaphylaxis or lack of resuscitation facilities. 87% of allergy clinic specialists report no reduction in the number of patients presenting as new referrals with suspected NRL allergy. These findings suggest a need for robust guidance to achieve more consistent investigative practice by those dealing with this condition.

Anaphylaxis during anesthesia: results of a 12-year survey at a French pediatric center

BACKGROUND

Following adverse reactions to anesthesia, tests are carried out to determine the mechanism of the reaction and to identify the agent responsible. No specific data are available in France concerning such skin tests in children.

METHODS

Between 1989 and 2001, we assessed hypersensitivity reactions to general anesthesia in 68 children. Thirty underwent more than one operation, for congenital malformations. Immunoglobulin (Ig)E-mediated anaphylaxis was diagnosed on skin tests combined with the clinical history.

RESULTS

Grade I, II and III reactions were observed in 20, 27 and 21 children, respectively. IgE-mediated anaphylaxis was diagnosed in 51 children: 31 (60.8%) for neuromuscular blocking agents (NMBA), 14 (27%) for latex, seven (14%) for colloids, five (9%) for opioids and six (12%) for hypnotics. Vecuronium was the NMBA causing the largest number of reactions. Cross reactivity to NMBA available in France was observed in 23 of 30 children (76%), particularly for vecuronium and atracurium or pancuronium. The estimated frequency of IgE mediated anaphylactic reactions was one in 2100 operations. Based on our results, 25 children subsequently received a different anesthetic with no adverse reaction.

CONCLUSIONS

As in adults, NMBA, then latex were responsible for most anaphylactic reactions during anesthesia. Our results confirm that skin tests with anesthetic agents are feasible and safe in children and improve the safety of subsequent anesthetic procedures.

The provision of dental care for patients with natural rubber latex allergy: are patients able to obtain safe care?

BACKGROUND

The number of people with allergy to natural rubber latex (NRL) has increased significantly in recent years.

AIM

To assess the experiences of latex-allergic patients in accessing appropriate dental care, and also the willingness and ability of general dental practitioners to provide care for these patients.

METHOD

Two self completing postal questionnaires, one to patients and one to general dental practitioners.

RESULTS

The majority of latex-allergic patients are able to obtain dental treatment. Some do experience adverse reactions, which may be severe, in spite of precautions being taken. Although many general dental practitioners are willing to accept such patients for treatment, few appear to be fully aware of all the necessary precautions required. Most do not have policies for the management of sensitised patients and staff, and a number are still using powdered natural rubber latex gloves in spite of the risk to patients and staff.

CONCLUSION

Latex-allergic patients can usually obtain safe treatment in general dental practice, but more education of dentists about the risks associated with natural rubber latex is required. Information about the latex content of equipment would be advantageous.

Toxicological and immunological aspects of occupational latex allergy

Latex allergy continues to be an important occupational health problem as latex products are used increasingly worldwide, particularly in healthcare. Although there are few epidemiological studies on the incidence of latex allergy, there has been an increase in the number of case reports over the last 10 years and, based on skin-prick tests, estimates of prevalence of latex allergy in healthcare workers range from 2% to 17%. The allergic health effects arise either from the latex proteins, generally causing a type I immediate hypersensitivity reaction, or from the chemicals added to latex during processing, causing a type IV delayed hypersensitivity reaction. Clinical manifestations of latex allergy depend on the route of exposure and occur by direct contact either with skin or mucosa, or by inhalation. The diagnosis of latex allergy is based on the history, skin tests, serological tests and challenge tests. Thirteen latex allergens have been identified and isolated so far from natural rubber latex. They differ in their potential to elicit immunological responses in individuals allergic to latex and thus have been designated as major or minor allergens. In latex gloves, cornstarch powder used as a donning agent carries latex proteins, thereby increasing inhalational and mucosal exposure to latex proteins. There also appears to be a positive correlation between protein content and allergenicity of gloves. The use of powder-free, low-protein gloves is effective in reducing symptoms and markers of sensitisation. Alternatives to latex gloves, such as nitrile or vinyl gloves are available but may be inferior in respect to manual dexterity and biological impermeability.

Latex allergy and skin

PURPOSE OF REVIEW

In this review we address the prevalence and outcome of latex allergy in health care workers (HCWs). Recent findings in natural rubber latex (NRL) allergens and trials of specific immunotherapy (SIT) are also of interest.

RECENT FINDINGS

A study involving skin prick test (SPT) screening in HCWs in Russia and adjacent countries found a prevalence of latex allergy of 1.9%. Questionnaire studies performed in Wales and in the USA identified prevalence rates of about 0.6%. An intervention undertaken at the Mayo Clinic, in which only gloves with low or undetectable allergen levels were allowed, reduced markedly the incidence of NRL allergy. Two studies, one from Finland and another from Ohio, showed that outcomes in latex-allergic HCWs are generally good. A study involving SPT screening showed that 6% of construction workers had latex allergy. A questionnaire study among allergists practicing in the USA showed that 62% performed latex SPT and 6% reported anaphylaxis, which mostly occurred while using a homemade SPT solution. Hev b 2, Hev b 5, Hev b 6.01 and Hev b 13 produced positive SPT reactions in over 60% of latex-allergic individuals. Topical application of NRL in a murine model of protein contact dermatitis caused a striking increase in prohevein-specific (Hev b 6.01) immunoglobulin E levels, together with a T-helper-2 type dermatitis. A placebo-controlled SIT trial with NRL extract alleviated cutaneous symptoms but caused some systemic reactions in latex-allergic patients.

SUMMARY

Low prevalence rates suggest that the peak of the latex allergy epidemic has already passed in HCWs. Hospital-wide interventions requiring use of low-allergen gloves reduce sensitization and changing gloves to nonlatex ones, or even using low-allergen latex gloves, in the affected individuals appears to confer adequate secondary prevention. In the USA there is an urgent need for standardized latex SPT reagent. Hev b 5 and Hev b 6.01 are major in vivo NRL allergens. Findings in mice suggest that NRL proteins eluting from latex gloves may also cause hand eczema in humans. SIT with NRL extract must still be considered an experimental treatment.

Increased prevalence of latex-sensitization among children with chronic renal failure

BACKGROUND

Type-I-allergy to natural rubber latex (NRL) has been shown to be more prevalent among certain groups of patients. Children suffering from chronic renal failure (CRF) could be a suspected risk group because of their intense exposure to latex through catheters, gloves and anesthetic equipment during frequent hospitalizations from early life on. We investigated the prevalence of latex-sensitization among this group of patients and sought to identify risk factors.

METHODS

Ninety-three patients (mean age 10.5 years) suffering from CRF were assessed by questionnaire-based history (details on renal disease, number and kind of surgical procedures, family and personal history of atopic diseases, allergic reactions to NRL, and the use of pacifiers) and by measurement of total and latex-specific serum immunoglobulin (Ig)E.

RESULTS

Ten of 93 (10.8%) patients showed elevated latex-specific IgE-levels. One of 10 patients reported clinical symptoms to latex-allergen, but no allergic reactions to NRL during medical care were reported. Sensitized patients were significantly more likely to be atopic, reflected by a positive history of other allergies as well as elevated total serum IgE-levels, and had a significantly higher number of urogenital surgeries (P = 0.02 in all cases, Fisher's exact and Wilcoxon test, respectively).

CONCLUSION

This study demonstrates that children with CRF are at increased risk of latex-hypersensitivity. Significant associations with atopy and repeated surgeries were observed. Larger studies are required to elucidate whether these children are also at increased risk of anaphylaxis and therefore deserve preventive measures.