The detection of clinically relevant contact allergens using a standard screening tray of twenty-three allergens

Systematic review on skin adverse effects of important hazardous hair cosmetic ingredients with a focus on hairdressers

BACKGROUND

The burden of occupational hand eczema in hairdressers is high, and (partly strong) allergens abound in the hair cosmetic products they use.

OBJECTIVES

To systematically review published evidence concerning contact allergy to an indicative list of active ingredients of hair cosmetics, namely, p-phenylenediamine (PPD), toluene-2,5-diamine (PTD), persulfates, mostly ammonium persulfate (APS), glyceryl thioglycolate (GMTG), and ammonium thioglycolate (ATG), concerning the prevalence of sensitization, particularly in terms of a comparison (relative risk; RR) between hairdressers and non-hairdressers.

METHODS

Following a PROSPERO-registered and published protocol, eligible literature published from 2000 to February 2021 was identified, yielding 322 publications, and extracted in standardized publication record forms, also considering risk of bias.

RESULTS

Based on 141 publications, the contact allergy prevalence to PPD was 4.3% (95% CI: 3.8-4.9%) in consecutively patch tested patients. Other ingredients were mostly tested in an aimed fashion, yielding variable, and partly high contact allergy prevalences. Where possible, the RR was calculated, yielding an average increased sensitization risk in hairdressers of between 5.4 (PPD) and 3.4 (ATG). Additional evidence related to immediate-type hypersensitivity, experimental results, exposures, and information from case reports was qualitatively synthesized.

CONCLUSIONS

An excess risk of contact allergy is clearly evident from the pooled published evidence from the last 20 years. This should prompt an improvement in working conditions and product safety.

Skin Toxicity of Selected Hair Cosmetic Ingredients: A Review Focusing on Hairdressers

The safety assessment of cosmetics considers the exposure of a 'common consumer', not the occupational exposure of hairdressers. This review aims to compile and appraise evidence regarding the skin toxicity of cysteamine hydrochloride (cysteamine HCl; CAS no. 156-57-0), polyvinylpyrrolidone (PVP; CAS no. 9003-39-8), PVP copolymers (CAS no. 28211-18-9), sodium laureth sulfate (SLES; CAS no. 9004-82-4), cocamide diethanolamine (cocamide DEA; CAS no. 68603-42-9), and cocamidopropyl betaine (CAPB; CAS no. 61789-40-0). A total of 298 articles were identified, of which 70 were included. Meta-analysis revealed that hairdressers have a 1.7-fold increased risk of developing a contact allergy to CAPB compared to controls who are not hairdressers. Hairdressers might have a higher risk of acquiring quantum sensitization against cysteamine HCl compared to a consumer because of their job responsibilities. Regarding cocamide DEA, the irritant potential of this surfactant should not be overlooked. Original articles for PVP, PVP copolymers, and SLES are lacking. This systematic review indicates that the current standards do not effectively address the occupational risks associated with hairdressers' usage of hair cosmetics. The considerable irritant and/or allergenic potential of substances used in hair cosmetics should prompt a reassessment of current risk assessment practices.

Importance of Supplemental Patch Testing Beyond a Screening Series for Patients With Dermatitis: The North American Contact Dermatitis Group Experience

IMPORTANCE

Patch test screening series for patients with dermatitis are limited and may miss clinically relevant contact allergens.

OBJECTIVE

To characterize individuals with dermatitis who showed clinically relevant patch test findings to supplemental (nonscreening) allergens or substances.

DESIGN, SETTING, AND PARTICIPANTS

A 17-year, retrospective cross-sectional analysis (January 1, 2001, to December 31, 2018) of North American Contact Dermatitis Group (NACDG) data from multiple centers in North America was conducted. A total of 43 417 patients with dermatitis underwent patch testing to the NACDG screening series in a standardized manner with 65 to 70 allergens and supplemental allergens as clinically indicated. Patients with 1 or more clinically relevant reactions to a supplemental (nonscreening) allergen/substance were analyzed between November 18, 2020, and March 12, 2021.

MAIN OUTCOMES AND MEASURES

The main outcomes were to assess the number of patients with clinically relevant reactions to supplemental (nonscreening) allergens and compare characteristics (including demographic characteristics and occupations) between patients with a clinically relevant patch test reaction to 1 or more supplemental allergens or substances (supplement-positive) and those without a reaction (supplement-negative) using odds ratios (ORs) and 95% CIs. Secondary outcomes included sources of allergic contact dermatitis and, for occupationally related cases, specific occupations and industries.

RESULTS

Of 43 417 patients included in the study who underwent patch testing to the NACDG screening series (65-70 allergens), 9507 individuals (21.9%) had currently relevant reactions to 1 or more supplemental allergens or substances. Of these, 6608 were women (69.5%) and the mean (SD) age was 47.2 (0.54) years. Compared with patients who had supplement-negative results, patients with supplement-positive findings were significantly less likely to be male (OR, 0.90; 95% CI, 0.85-0.94; P < .001) and/or have atopic dermatitis (OR, 0.89; 95% CI, 0.84-0.93; P < .001). Common primary sites of dermatitis in 9499 patients with supplement-positive findings included the face (2856 [30.1%]), hands (2029 [21.4%]), and scattered/generalized distribution (1645 [17.3%]). Frequent sources of supplemental allergens in 9235 patients included personal care products (4746 [51.4%]) and clothing/wearing apparel (1674 [18.1%]). Of 9362 patients with available data, supplemental allergens/substances were occupationally related in 1580 (16.9%); of those with identified occupations, 25.1% (384 of 1529) were precision production, craft, or repair workers. Of 9507 patients with supplement-positive findings, 2447 (25.7%) had no currently relevant reactions to NACDG screening allergens.

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that 21.9% of patients who underwent patch testing to an allergen screening series of 65 to 70 allergens had at least 1 relevant reaction to supplemental allergens/substances. Of these, one-quarter reacted only to a supplemental allergen/substance. Screening series include common, important allergens, but these findings suggest that the addition of specialty allergens and personal or work products is critical for the successful diagnosis and management of allergic contact dermatitis.

Prevalence of Surfactant in the Contact Allergen Management Program

BACKGROUND

Surfactants are common ingredients in topical products, which can cause both irritant and allergic contact dermatitis.

OBJECTIVE

The aim of this study was to determine the prevalence of 12 common groups of surfactants and 12 common individual surfactants among products in each category in the American Contact Dermatitis Society Contact Allergen Management Program (CAMP).

METHODS

The American Contact Dermatitis Society CAMP was queried for the 12 surfactant groups and the 12 individual surfactants.

RESULTS

The laureth/pareth sulfate group was the most prevalent surfactant group in CAMP products (17.9%). Laureth/pareth sulfates were the most common surfactant group in all product categories, except household and eye care products. The betaine/sultaine group (13.5%) and glucosides (10.0%) were also found in a significant proportion of CAMP products. Oleamidopropyl dimethylamine has the highest positive reaction rate (3.5%) but was tied for the lowest prevalence (0.20%) of the 12 individual surfactants studied. In contrast, cocamidopropyl betaine has a lower positive reaction rate (1.6%) with a higher prevalence (10.4%).

CONCLUSIONS

Surfactants were commonly found across all product types in CAMP. This study provides important information on allergen and irritant exposures in care products.

Patch Testing Pearls

Dermatitis is one of the most common illnesses encountered by healthcare providers and the causes are numerous. Contact dermatitis is the form of dermatitis resulting from contact with the environment, and it may be either irritant or allergic in nature. Patch testing has been the gold standard for diagnosis of allergic contact dermatitis since its formal description over 100 years ago by Jadassohn. While this diagnostic tool may seem simple to us today, there are numerous potential points for error that the practitioner must keep in mind. Patient selection, technique of patch test placement, allergen selection, patch test reading and interpretation, and patient management all must be considered. To simply apply a given set of test allergens indiscriminately and not be prepared to interpret the results accurately with patient education and management in mind would be a great failure. Conversely, with experience and the proper knowledge base some of the most complex dermatitis questions can be answered.

Immediate and Delayed Hypersensitivity Reactions to Corticosteroids: Evaluation and Management

Corticosteroids are anti-inflammatory medications used widely to treat allergic inflammation. Although the endocrine and gastrointestinal side effects of corticosteroids have been described, the occurrence of immediate hypersensitivity reactions and delayed contact dermatitis due to corticosteroids remains under-recognized. Hypersensitivity reactions can occur to a corticosteroid itself, or to the additives and vehicles in corticosteroid preparations. Skin testing and oral graded challenge can help confirm the suspected culprit agent in immediate hypersensitivity reactions and help identify an alternative tolerated corticosteroid. Patch testing can help identify the culprit agents in delayed hypersensitivity contact dermatitis. Cross-reactivity patterns have not been observed for immediate hypersensitivity reactions as they have been for delayed contact dermatitis. Sensitization in contact dermatitis exhibits cross-reactivity patterns based on corticosteroid structure. We review the current understanding regarding the clinical presentation, evaluation, and management of immediate and delayed hypersensitivity reactions to corticosteroids.

Review of allergic contact dermatitis: Scratching the surface

Contact dermatitis-including allergic contact dermatitis (ACD)-n and results in over four million lost work days per year in the United States alone. ACD is a classic example of a type IV delayed hypersensitivity reaction, and represents a significant burden on the health system, economy, and patient quality of life. Thorough history taking, clinical examination, histologic evaluation, and patch testing are keys to diagnosing contact dermatitis. Patch testing, especially with comprehensive and customized panels based on the patient’s exposure history, is particularly useful in identifying potential allergens in the case of allergic contact dermatitis. ACD management requires a combination of direct medical intervention, patient education, and appropriate environmental modification to prevent exposure to offending allergens in the home or workplace. Continuing advances in the study of ACD has led to an increased understanding of the disease processes, new methods for diagnosis, and improved management. This article reviews ACD-aiming to connect recent investigational data with the current clinical understanding of disease pathophysiology, diagnostic techniques, and management strategies.

Role of mast cells in mucosal diseases: current concepts and strategies for treatment

Mast cells are well known for their role in type I hypersensitivity. However, their role in the immune system as well as their pathophysiological role in other diseases is underacknowledged. The role of mast cells in inflammatory bowel disease, allergic contact dermatitis and asthma is illustrated in this review. The contribution of mast cell activation in these diseases is controversial and two alternative means are proposed: activation via stress response pathways and immunoglobulin-free light chains. Activation of the mast cells leads to release of preformed mediators and to generation of other potent biological substances that have both physiological and pathophysiological effects. The role of these mediators in the aforementioned diseases is also outlined in this review. When the roles of mast cells are better understood, drugs specifically targeting mast cells may be developed to effectively treat a wide range of diseases.

Hand eczema

Hand eczema is an inflammation of the skin; the cause is often multifactorial. Initial management includes avoiding causative irritants or allergens (e.g., by wearing impermeable gloves) and applying emollients and potent topical glucocorticoids.

A multi-center, retrospective review of patch testing for contact dermatitis in allergy practices

BACKGROUND

Studies assessing patch testing (PT) in allergy practices are limited.

OBJECTIVES

To determine whether PT results using a limited panel of allergens such as in the Thin-Layer Rapid-Use Epicutaneous Test (TT) as compared with an expanded panel, such as the addition of supplemental allergens (North American Contact Dermatitis [NACD] Panel, Dormer Cosmetics, hairdressing series, corticosteroid series, and personal products) will miss a significant number of positive PTs. To compare our PT results with published data from dermatology practices.

METHODS

This is a 5-year multicenter retrospective chart review of PT at 3 separate allergy practices.

RESULTS

Four hundred twenty-seven patients (mean age, 49.8 years) were patch tested. Eighty-two percent were female; 54% reported an atopic history. Of the standardized allergens, the 5 most common positives were nickel sulfate, fragrance mix I, p-phenylenediamine (PPD), thimerosal, and cobalt chloride. Two hundred eighteen (56.9%; 95% CI = 51.9-61.8%) patients were positive to at least 1 TT allergen. Ninety-eight (25.6%; 95% CI = 21.5-30.2%) patients were positive to both a TT and a supplemental allergen. Forty-eight (12.5%; 95% CI = 9.6-16.2%) patients were negative to a TT allergen but positive to a supplemental allergen.

CONCLUSION

Positive allergens would have been missed in 12.5% of patients when evaluating with TT allergens alone, whereas 25.6% would be partially evaluated. Patch test performance characteristics for these allergy practices appear to parallel that seen for dermatology. The TT remains an adequate screening tool in an allergy practice, but a more comprehensive panel may be needed to fully evaluate contact dermatitis.

[Indications for referral to a skin allergy unit]

Contact dermatitis is one of the most common reasons for consultation in dermatology. However, general dermatologists do not always appreciate the importance of patch testing. These tests should ideally be performed in specialist skin allergy units, most importantly in cases suggestive of contact dermatitis, severe acute dermatitis, chronic persistent dermatitis, and dermatitis affecting the eyelids, genital region or adjacent to venous ulcers. Eczematous changes in pre-existing skin lesions or lesions at atypical sites in patients diagnosed with atopic eczema should also be investigated. Finally, cases diagnosed as occupational dermatitis can be best managed by the workers' health insurance scheme.

Results of patch testing to personal care product allergens in a standard series and a supplemental cosmetic series: an analysis of 945 patients from the Mayo Clinic Contact Dermatitis Group, 2000-2007

BACKGROUND

Patch testing to a standard screening series of allergens in combination with supplemental cosmetic allergens is often used to diagnose allergic contact dermatitis due to personal care products.

OBJECTIVE

To report results of patch testing to skin care product allergens contained in a standard series and a supplemental cosmetic series and to compare efficacy of this combined series in detecting positive reactions to personal care product allergens with the efficacy of various standard screening series.

METHODS

Positive reaction rates to skin care product allergens were tabulated for patients who underwent patch testing to both standard and cosmetic series allergens at Mayo Clinic between 2000 and 2007. Data were compared with skin care allergens detected on standard screening series, including the thin-layer rapid use epicutaneous (TRUE) test.

RESULTS

Of 945 patch-tested patients, 68.4% had at least one positive reaction and 47.3% had at least two positive reactions. Also, 49.4% of patients reacted to at least one preservative; 31.2% reacted to at least one fragrance/botanical additive. Compared with use of our standard series and cosmetic series, use of the TRUE test would have missed 22.5% of patients with preservative allergy, 11.3% with fragrance/botanical allergy, and 17.3% with vehicle allergy.

LIMITATIONS

Various allergens tested over time, patch test reading by residents, and lack of confirmation of allergen in personal care products.

CONCLUSION

Standard patch-test screening series miss a substantial number of patients with skin care product ingredient allergy.

Elicitation of the immune response to p-phenylenediamine in allergic patients: the role of dose and exposure time

BACKGROUND

Usage of hair dye products containing p-phenylenediamine (PPD) is a concern for PPD-allergic individuals.

OBJECTIVES

The present study investigates the role of dose and exposure time on elicitation of allergic contact dermatitis under conditions of permanent hair dyeing.

METHODS

Elicitation responses after application of a typical hair dye product containing 2% PPD for 30 min followed by rinsing were analysed in 38 PPD-allergic individuals with a documented history of hair dye-related allergy. Skin binding experiments in vitro were performed to distinguish the dose available for elicitation from the dose applied.

RESULTS

A positive reaction was elicited in 20 of 20 patients with grades ++ to +++ and 12 of 18 with grade + according to the classification of the International Contact Dermatitis Research Group. Under conditions of diagnostic patch testing (48 h exposure), the dose available for elicitation is more than 10-fold higher compared with the dose available for hair dyeing (30-min exposure, rinsing of product).

CONCLUSIONS

This investigation demonstrates that under simulated hair dye use conditions the actual exposure to PPD is more than an order of magnitude lower than under diagnostic patch testing, although sufficient to elicit a clearly noticeable reaction in 84% of PPD patch test-positive individuals.

Contact Allergens in Persons With Leg Ulcers: A Canadian Study in Contact Sensitization

Individuals with chronic leg ulcers often develop contact allergic reactions to topical preparations used to treat their wounds and the surrounding skin. The objective of this study was to determine the frequency of positive patch test responses to common allergens in patients with leg ulcers or venous disease. A case series of 100 consecutive, consenting patients with chronic venous disease and other causes of leg ulcers that were available for patch testing were enrolled. The patients were tested with 38 common allergens, including those most relevant to leg ulcers. A total of 46% of the patients had at least 1 positive patch test response. Multiple reactions in the same patient were common. The most frequent groups of sensitizers were fragrances, lanolin, antibacterial agents, and rubber-related allergens. Though the prevalence of positive patch test reactions is high in this population, it is lower than commonly reported. This may be the result of clinical practice that considered the avoidance of common sensitizers in the management of patients with leg ulcers.

Allergic contact dermatitis to topical antibiotics: Epidemiology, responsible allergens, and management

Topical antibiotics are widely used to treat cutaneous, ocular, and otic infections. Allergic contact dermatitis to topical antibiotics is a rare but well-documented side effect, especially in at-risk populations. The purpose of this article is to review the epidemiology, responsible allergens, and management of allergic contact dermatitis to topical antibiotics.

LEARNING OBJECTIVE

After completing this learning activity, participants should be able to describe the epidemiology of allergic contact dermatitis related to topical antibiotics; show knowledge of the most common allergenic topical antibiotics; and understand the allergenic cross-reactivity pattern amongst topical antibiotics.

Patch testing: pitfalls and performance

PURPOSE OF REVIEW

Contact dermatitis is a common disease process that includes allergic and irritant contact dermatitis. The gold standard for diagnosing allergic contact dermatitis, a type IV delayed hypersensitivity reaction, is patch testing. Patch testing is not a difficult procedure, however, there are several critical components that determine the success of the test: having an appropriate level of suspicion for the diagnosis of allergic contact dermatitis, an adequate threshold for patch testing, the necessary experience to properly interpret the results and to determine their relevance, and the ability to thoroughly educate the patient about the condition.

RECENT FINDINGS

Research shows that patch testing practices differ among individuals and specialties. The level of patch testing education, interest in, and experience with, the procedure can affect the results of the test. Some of these practice differences and how they affect the outcome of patch testing are highlighted.

SUMMARY

Physicians' knowledge and experience with patch testing, their level of interest and access to allergens will determine the performance of this test, the reliability of the results and the benefits gained from this procedure.

Dermatitis de manos

Hand dermatitis is a common skin disease that often has a chronic and relapsing course. Several subtypes of hand dermatitis have been described. In this review, we describe the clinical characteristics of each form of hand eczema, laboratory tests helpful in the diagnosis, and treatment options for this condition.

Patch testing: a retrospective analysis of 103 patients with emphasis on practical aspects for the clinician

BACKGROUND

Allergic contact dermatitis is a common dermatologic disorder caused by small chemical molecules that can penetrate the skin barrier. Thousands of chemicals capable of inducing allergic contact dermatitis have been identified. To cure allergic contact dermatitis, the allergen should be identified and eliminated from the environment of the patient. Patch testing, utilizing a variety of standard panels of the most frequent allergens, is used to identify the allergen in question. Patch testing is still the gold standard tool used to identify one or more substances that may contribute to the etiology of allergic contact dermatitis.

OBJECTIVE

To determine the frequency of patch test positivity and to identify the most common allergens in patients with suspected allergic contact dermatitis.

METHODS

A retrospective analysis of files of 103 patients who have been clinically diagnosed to have allergic contact dermatitis and have been patch tested using a standard technique with a Northern American Contact Dermatitis Group series.

RESULTS

Sixty-two patients (60.2%) showed positive reactions to one or more substance. The most common allergens were nickel sulfate, fragrance mix, and neomycin sulfate. There was an increased frequency of positive reactions to fragrance mix and a significant decrease of frequency of thimerosal positive reactions.

CONCLUSIONS

Increased awareness of allergens and their potential sources may help to limit the usage of these chemicals in manufacturing consumer products. This may have contributed to decreased prevalence rates of certain allergens such as thimerosal and paraphenylenediamine.

Patch test results from the Mayo Clinic Contact Dermatitis Group, 1998-2000

BACKGROUND

Patch testing is a diagnostic tool for the evaluation of patients with suspected allergic contact dermatitis. A standard series of allergens similar to that used by the North American Contact Dermatitis Group (NACDG) is used at Mayo Clinic.

OBJECTIVE

Our aim was to report the results of patch testing with a standard series at Mayo Clinic from July 1, 1998, to Dec 31, 2000 and to compare our findings with those of the NACDG during the same period.

METHODS

The results of patch testing with the standard series at Mayo Clinic were examined. Positive reaction rates were compared between Mayo Clinic and the NACDG.

RESULTS

During the 30-month period, 1324 Mayo Clinic patients were patch tested with a standard series of allergens (mean, 60 allergens), whereas the NACDG standard series during this period included 50 allergens. Overall, 917 patients (69.3%) had at least one positive reaction and 606 patients (45.8%) had two or more positive reactions. The 10 allergens used both by Mayo Clinic and by the NACDG that most frequently caused positive reactions were nickel sulfate hexahydrate, balsam of Peru (Myroxylon pereirae), neomycin sulfate, cobalt chloride, fragrance mix, potassium dichromate (0.25%), thimerosal, bacitracin, formaldehyde, and glutaraldehyde. Statistically significant differences in positive reaction rates (P < .05) were observed for 12 of the 43 allergens common to both Mayo Clinic and the NACDG.

CONCLUSION

With large standard patch test series, one can identify commonly encountered and potentially relevant contact allergens.

Improved detection of allergen-specific T-cell responses in allergic contact dermatitis through the addition of 'cytokine cocktails'

The gold standard for the diagnosis of allergic hypersensitivity is skin patch testing with the suspected allergens. This diagnostic tool, however, has distinct disadvantages, and therefore the development of alternative or complementary in vitro tests is of great importance. In this study, we evaluate the applicability of an in vitro test method, as developed earlier for nickel allergy, to detect allergen-specific T cells in the blood of patients allergic to frequent sensitizers (chromate, cobalt, paraphenylenediamine, fragrances and chloromethyl-isothiazolinone). Peripheral blood mononuclear cells (PBMCs) of allergic patients and healthy controls were cultured in the absence or presence of allergen. Additionally, type 1 (IL-7 and IL-12) or type 2 (IL-7 and IL-4) stimulating cytokines were added; after 6-day proliferation, IFN-gamma and IL-5 secretions were determined. Without the addition of cytokines, consistent allergen-induced proliferation was observed in PBMCs of nickel-allergic patients only. By contrast, the addition of type 1 or type 2 stimulating cytokines resulted in a significantly enhanced allergen-specific proliferation for all allergens tested (sensitivity increased from 26 to 43% or 38%, respectively, P < 0.05). In these cultures, allergen-induced IFN-gamma and IL-5 secretion was also significantly increased, compared to healthy controls (P < 0.05, for IFN-gamma sensitivity 79%, specificity 93%; for IL-5 sensitivity 74%, specificity 81%). In conclusion, these results demonstrate an increased proliferative capacity and cytokine production by allergen-specific T cells from allergic patients, but not of healthy individuals upon stimulation with allergens in combination with type 1 or 2 skewing cytokines. The present data warrant further exploration of the application of this test to a broader set of allergens.

Occupational allergens in dentistry

PURPOSE OF REVIEW

Dental professionals and their physicians frequently do not recognize, accurately diagnose or appropriately manage occupational allergies. Dental allergen identification, diagnostics and practical avoidance strategies are summarized in this review.

RECENT FINDINGS

Methacrylates, natural rubber latex proteins, rubber glove allergens, and glutaraldehyde are the predominant allergens in dentistry. Reactions range from cell-mediated contact allergy to urticaria and occupational asthma.

SUMMARY

Despite recent advances in allergen characterization and increased awareness of selected allergens, treatment of occupational allergies can be improved. Better information and improved cooperation between dental workers and their clinicians is needed.

Contact allergy to neomycin sulfate: results of a multifactorial analysis

PURPOSE

To perform a comprehensive, multifactorial analysis of potential risk factors (demographic and clinical) for contact allergy to neomycin sulfate, a common adverse reaction resulting from the topical use of this drug; especially in some subgroups of the population.

METHODS

Retrospective analysis of allergy test data of the Information Network of Departments of Dermatology (IVDK, www.ivdk.org) between 1998 and 2003, including all patients patch tested with a standard screening series because of suspected allergic contact dermatitis (ACD). As one outcome, a positive (allergic) test reaction to neomycin sulfate was considered. An alternative outcome included only those patients with a positive test to neomycin sulfate and a final diagnosis of ACD. The association between outcome and potential risk factors was analyzed with Poisson regression analysis, deriving prevalence ratios (PR) as risk estimates.

RESULTS

Of the 47,559 patients tested, 2.5% had positive reactions to neomycin sulfate, while in 1.1% ACD was additionally diagnosed. The results of the multifactorial analysis indicated that the risk of both outcomes decreased slightly during the period covered; was higher among patients with leg dermatitis; varied significantly with age and increased progressively with the number of additional positive reactions to other standard series allergens. Cross-reactivity to other, selectively tested, aminoglycoside antibiotics was substantial (kappa = 0.67; 95%CI: 0.63-0.71) for framycetin sulfate, to low (kappa = 0.33; 95%CI: 0.27-0.37) for gentamicin sulfate.

CONCLUSIONS

The prevalence of contact sensitization to neomycin sulfate was noteworthy among patients patch tested in the IVDK centers. Supplementing clinical epidemiology, neomycin contact allergy has been estimated to be relatively common even on the level of the unselected population (prevalence approx. 1%). Hence, the topical use of neomycin sulfate by patients should be carefully monitored, considering its potential to induce ACD, with emphasis on subgroups at risk.

Patch testing with a standard allergen ("screening") tray: rewards and risks

The TRUE Test panels, which are the only patch testing devices approved by the Food and Drug Administration in the US, consist of 24 patches, one of which is a negative control. The remaining 23 patches contain 42 unique allergens and four complex mixtures. Although these panels contain approximately 1.4% of the > 3700 known allergens, they perform robustly in detecting allergic contact dermatitis (ACD). Twenty-eight percent of patients are fully evaluated by application of TRUE Test((R)). The present paper reviews the appropriate use of the TRUE Test panels. The need to determine relevance of any positive reaction is stressed. The common causes of false-positive and false-negative reactions are outlined. Those product types where the TRUE Test panels detect the majority of relevant allergic reactions are reviewed, as are the other sources of exposure to the allergens on these panels. The impact of ACD on quality of life is significant. Only by patch testing can the diagnosis be made.