Patch testing with natural rubber latex

Allergic contact dermatitis from natural rubber latex in atopic dermatitis and the risk of later Type I allergy

The aims of the study were to assess whether contact dermatitis in children could be due to a delayed hypersensitivity reaction to natural rubber latex (NRL) and to define risk factors for later occurrence of Type I hypersensitivity to this allergen. Among 1800 children investigated for contact dermatitis, 55 were referred on suspicion of rubber allergy and had patch tests to NRL, as well as prick tests and blood tests for specific immunoglobulin E (IgE). A 2-year follow-up was then carried out. Delayed hypersensitivity to NRL was confirmed in 32 children. Patch testing with NRL proved to be positive, and clinical improvement confirmed the diagnosis and relevance of patch tests. 30 of these 32 patients had associated atopic dermatitis (AD). Prick tests and blood tests for specific IgE to latex were negative at the time of diagnosis. A 2-year follow-up showed that 10 of 27 patients presenting initially with a positive patch test without associated Type I sensitization later developed immediate hypersensitivity. Children with AD are at high risk for allergy to NRL protein. Exclusion of this allergen should be strongly advised in atopics because of the dual risk of dermatitis and later evolution into severe Type I hypersensitivity.

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.

Cataract surgery for natural rubber latex allergic patients

The prevalence of reactions against natural rubber latex (NRL) is thought to be increasing in both the general public and healthcare workers. These can vary from mild benign skin reactions to bronchospasm, anaphylactic shock, and death. Difficulties exist for ophthalmic departments wishing to establish protocols in providing 'latex-free environments' for patients undergoing cataract surgery. Currently no legislation exists regarding the labelling of NRL-containing products in the United Kingdom with information on a product's NRL content provided by the manufacturer on a voluntary basis only. It is hoped this review article will act as a basic guide in the management of NRL-sensitive patients undergoing cataract surgery in the United Kingdom.

Occupational contact dermatitis. Recognition and management

Occupational contact dermatitis (OCD) represents 90 to 95% of all occupational dermatoses. The incidence rate of OCD is estimated to be around 0.5 to 1.9 cases per full-time worker per year. However, epidemiologic data are lacking and incidence is probably underestimated, especially in the US. Over the past 20 years, OCD has been the most frequently reported occupational disorder to German social insurance institutions. Critical factors in the management of OCD are recognition of clinical features, knowledge of allergens and irritants present in different occupational fields, knowledge of suitable protection, interpretation of patch test results, and awareness of medicolegal aspects. Management of OCD should be carried out by dermatologists and patch test clinics in cooperation with physicians specialized in industrial medicine. Individuals at high risk of OCD are hairdressers, dental laboratory technicians, other healthcare workers, construction industry workers, metal workers, leather and shoe manufacturers, florists and gardeners, and bakers, caterers, confectioners and cooks.

Type IV hypersensitivity reactions to natural rubber latex: results of a multicentre study

BACKGROUND

Positive patch test reactions to natural rubber latex (NRL) have been interpreted as allergic or irritant by different groups. Additives to the NRL test solution have also caused positive reactions in previous studies.

OBJECTIVES

Five centres of the British Contact Dermatitis Group conducted a prospective study on the prevalence of type IV hypersensitivity to NRL, using ammonia-preserved NRL solution for testing.

PATIENTS AND METHODS

A total of 2738 consecutive patients were patch tested. Where clinically indicated, specific IgE was measured or a prick test done.

RESULTS

Twenty-seven patients (1%) had a positive patch test reaction to NRL, which was considered to be allergic and of current relevance in 19 (70%) patients. Fourteen of these also had a positive prick test or specific IgE. Thirteen patients (48%) were male, 19 (70%) atopic and 13 (48%) had eczema on their hands.

CONCLUSIONS

We conclude that delayed-type hypersensitivity to NRL is a problem for a proportion of patients with eczema, particularly on their hands, and that patch testing with ammonia-preserved NRL can be recommended to identify these patients. Patients with a positive patch test should be investigated for contact urticaria to NRL.

Occupational contact dermatitis in nurses with hand eczema

Occupationally related dermatitis is a common problem in nurses, who are exposed to a wide variety of allergenic and irritant substances. In a group of 44 nurses with hand dermatitis (40 female, 4 male), 18 were thought to have a predominantly allergic contact dermatitis, 15 an irritant dermatitis, 7 other form of eczema, 3 atopic dermatitis and one pompholyx. 10 of the 15 irritant cases were diagnosed as occupational. Of the 18 patients with allergic contact dermatitis, the allergens were thought to be occupationally relevant in 8 cases. In 6 of these 8 the dermatitis was due to natural rubber latex (3) or other rubber chemicals (3). 2 had additional evidence of immediate-type hypersensitivity to natural rubber latex (one was patch test allergic to latex, the other to thiuram mix). Natural rubber latex allergy, both delayed and immediate, is a significant problem, and nurses at risk should be tested for both types of hypersensitivity, as well as being patch tested to standard, rubber and medicaments series.

Latex allergy

Latex allergy continues to be an important medical problem. In this review we re-examine the definition of latex allergy, the offending allergens, the factors that enhance sensitization, the threshold levels that sensitize and elicit reactions in sensitized individuals, current diagnostic techniques, avoidance measures, the barrier properties of nonlatex alternatives, and the roles of premedication and immunotherapy. Twenty years after its resurgence, latex allergy is a well-defined condition with established diagnostic criteria and rational treatment and prevention strategies. However, in spite of advances associated with molecular studies of latex allergens and improved understanding of immunotherapy, avoidance remains the only effective treatment.

The problems of rubber hypersensitivity (Types I and IV) in chronic leg ulcer and stasis eczema patients

The prevalence of Type I and Type IV hypersensitivity to rubber allergens in patients with stasis eczema and/or venous leg ulcers over an 18-month period was studied by prick and patch testing. Results from 109 patients were analysed. Positive patch tests were found in 71 patients (65%). Delayed-type hypersensitivity to rubber chemicals was found in 17 patients (15.6%). However, only 1 patient who had additional risk factors showed Type I hypersensitivity to natural rubber latex. We therefore conclude that, although Type IV hypersensitivity to rubber chemicals is relatively common in our patients, Type I hypersensitivity to natural rubber latex remains rare.

Natural rubber latex allergy

Rubber is an important industrial and consumer product encountered in many household items and medical devices. Whereas the chemical additives used in its manufacture are well recognized as a cause of delayed-type hypersensitivity (allergic contact dermatitis), it is only during the past decade that immediate-type allergy to natural rubber latex (NRL) proteins (latex allergy) has emerged as a serious health issue. Frequent, prolonged wearing of NRL gloves, especially amongst health care workers, is a major risk factor for such sensitization. Latex allergy is now an important medical, occupational, medico-legal and financial problem, and it is essential that policies are developed to reduce it. Undiagnosed latex allergy is potentially very serious for patients. This article briefly overviews latex allergy with emphasis on the practical issues of diagnosis and management.