Allergic and irritant patch test reactions and atopic disease

Sensitizing agents found in children and adolescents with recalcitrant atopic dermatitis: a cross-sectional study with a pediatric battery

BACKGROUND

Atopic dermatitis is the most common inflammatory skin disease in childhood and has an important impact on quality of life, especially severe cases or those that are recalcitrant to treatments. Sensitization to allergens with the potential for allergic contact dermatitis is a factor associated with cases of recalcitrant atopic dermatitis. Understanding the relationship between atopic dermatitis, allergens, and allergic contact dermatitis is essential. In Brazil, there are no studies on sensitization to allergens found in patch tests with pediatric batteries in patients with atopic dermatitis.

OBJECTIVES

To verify the main sensitizing agents, the prevalence of allergic contact dermatitis and the epidemiological and clinical profile of children and adolescents with atopic dermatitis.

METHODS

Cross-sectional, prospective study in patients between 4 and 18 years of age, with recalcitrant atopic dermatitis, treated at the Sanitary Dermatology Outpatient Clinic (RS). All patients underwent patch tests with a battery of pediatric allergens.

RESULTS

The prevalence of sensitization and allergic contact dermatitis in the evaluated patients was 37.07% (20/54) and 27.7% (15/54), respectively. The most frequent allergens were: nickel sulfate (16.7%), disperse blue (5.6%), and fragrance mix I (5.6%). Nickel was associated with the female sex (p = 0.019).

STUDY LIMITATIONS

Sample size and selection, absence of a control group.

CONCLUSIONS

A proportion of patients with recalcitrant atopic dermatitis may be sensitized to different allergens and may even have developed allergic contact dermatitis. Recognizing this context is important in the prevention strategy and management of the disease.

Atopy patch testing with aeroallergens in a large clinical population of dermatitis patients in Germany and Switzerland, 2000-2015: a retrospective multicentre study

BACKGROUND

The diagnostic significance of the atopy patch test for the management of dermatitis possibly triggered by aeroallergens is still controversial. However, sufficiently large studies with routinely tested standardized aeroallergen patch test preparations in dermatitis patients are lacking.

OBJECTIVE

To evaluate the reaction frequency and the reaction profiles of 10 until mid-2015 commercially available, standardized aeroallergen patch test preparations of the 'Stallerpatch' test series (Stallergenes, Antony Cedex, France) in a large multicentre patient cohort.

METHODS

A retrospective data analysis of patients with suspected aeroallergen-dependent eczematous skin lesions was performed, who were patch tested in 15 Information Network of Departments of Dermatology-associated clinics between 2000 and 2015. Patients were stratified according to their atopic dermatitis (AD) status.

RESULTS

The study group included 3676 patients (median age 41 years, 34.8% males, 54.5% AD). The most common aeroallergens causing positive patch test reactions were Dermatophagoides pteronyssinus (19.6%), Dermatophagoides farinae (16.9%), birch (6.2%), timothy grass (6.0%), cat dander (5.4%), mugwort (4.9%) and dog dander (4.6%). Reactions to other pollen allergen preparations, that is 5 grasses (3.2%), cocksfoot (2.1%) and plantain (1.6%), were less common. Positive patch test reactions to aeroallergens were consistently more frequent in patients with AD. These patients showed proportionally less dubious, follicular, irritant and weak positive reactions. Independent of AD status, a patient history of past or present allergic rhinitis was associated with an increased chance of a positive aeroallergen patch test reaction to pollen allergens.

CONCLUSION

The aeroallergen patch test is a useful add-on tool in clinical routine, especially in patients with AD and/or respiratory allergy. A patch test series comprising Dermatophagoides pteronyssinus, Dermatophagoides farinae, birch, timothy grass, cat dander and mugwort seems to be suitable. Controlled studies with specific provocation and elimination procedures are required to further evaluate the diagnostic significance of the proposed screening series.

Contact sensitization in children with atopic dermatitis

BACKGROUND

Atopic dermatitis is a common illness in childhood. Children with atopic dermatitis are prone to develop cutaneous sensitization due to skin barrier dysfunction.

AIM

The aim of this study was to evaluate the frequency of cutaneous sensitizations in patients with atopic dermatitis and to identify the most frequent causative allergens.

STUDY DESIGN

The study group consisted of 112 children with atopic dermatitis, aged 1-18 years (median 88.5 months) and 39 healthy controls, aged 1-8 years (median 88.48 months).

METHODS

The diagnosis of atopic dermatitis was established by modified Hanifin and Rajka criteria; severity of the disease was assessed by scoring of atopic dermatitis. Serum blood eosinophil count, total IgE and skin prick tests for common aeroallergens and food allergens were performed. Patch tests with cosmetic series and European standard patch test series (Stallegenes© Ltd, Paris, France) were applied.

RESULTS

Of the children with atopic dermatitis, 17% (n=19) were sensitized to either cosmetic or standard series or both of them; no children in the control group had a positive patch test (p=0.001). Atopy and severity of atopic dermatitis was not a significant risk factor for cutaneous sensitization. The most common allergens were Nickel sulphate and Methychloroisothiazinolone (4.5% and 4.5%) in the European standard patch test and cocamidoproplybetaine (12.5%) in the cosmetic series patch test.

CONCLUSION

Cutaneous sensitization can develop in children with atopic dermatitis, therefore allergic contact dermatitis should be kept in mind.

Both children and adult patients with difficult-to-treat atopic dermatitis have high prevalences of concomitant allergic contact dermatitis and are frequently polysensitized

BACKGROUND

Concomitant allergic contact dermatitis (ACD) has been described as a possible cause of atopic dermatitis (AD) becoming difficult-to-treat. However, contact sensitization in this patient group has barely been studied.

OBJECTIVE

To study the occurrence of ACD in a population of difficult-to-treat AD children and adults.

METHODS

Clinical and patch test information of 48 patients with difficult-to-treat AD unresponsive to conventional outpatient treatments was gathered retrospectively. We studied prevalence and relevance of common allergens, performed dynamic patch test analysis and assessed occurrence of polysensitization.

RESULTS

In 48 patients with difficult-to-treat AD, 75% (n = 36/48) had a concomitant contact allergy, and 39% (n = 14/36) of these patients were polysensitized. ACD and polysensitization prevalences were equal amongst children and adults. The most frequent and relevant reactions were seen against wool alcohols, surfactants cocamidopropyl betaine and dimethylaminopropylamine, bichromate and fragrance mix I. Dynamic pattern analysis showed these reactions to be mostly allergic and not irritative of nature.

CONCLUSION

Difficult-to-treat AD patients frequently suffer from concomitant (multiple) contact allergies, and this may be a reason why the AD turns into a difficult-to-treat disease. Awareness of this phenomenon is necessary, as pragmatic implementation of allergen avoidance strategies may be helpful in getting disease control in this population.

EAACI position paper for practical patch testing in allergic contact dermatitis in children

INTRODUCTION

Allergic contact dermatitis (ACD) in children appears to be on the increase, and contact sensitization may already begin in infancy. The diagnosis of contact dermatitis requires a careful evaluation of a patient's clinical history, physical examination, and skin testing. Patch testing is the gold standard diagnostic test.

METHODS

Based on consensus, the EAACI Task Force on Allergic Contact Dermatitis in Children produced this document to provide details on clinical aspects, the standardization of patch test methodology, and suggestions for future research in the field.

RESULTS

We provide a baseline list of test allergens to be tested in children with suspected ACD. Additional tests should be performed only on specific indications.

Contact sensitivity in patients with recalcitrant atopic dermatitis

Patients with atopic dermatitis are usually responsive to conventional treatment such as topical steroids; however, they are sometimes refractory to the treatment. The influence of contact sensitivities on the course of patients with recalcitrant atopic dermatitis is not known. The aim of this study was to investigate whether contact sensitivities affect the course of patients with recalcitrant atopic dermatitis. We evaluated 45 patients with atopic dermatitis who had failed conventional therapy. Patch testing was performed with the Japanese standard series, metal series and/or suspected items. A total of 15 patients had a positive patch test reaction to at least one allergen. The most common allergens were nickel, topical drugs and rubber accelerators. Avoidance of products or food containing allergic substances greatly or partially improved skin symptoms in nine patients. These results suggest that contact allergens and metals may be critical factors causing eczematous lesions in patients with recalcitrant atopic dermatitis.

Allergic contact dermatitis in children: which factors are relevant? (review of the literature)

Allergic contact dermatitis (ACD) in children is increasing. Sensitization to contact allergens can start in early infancy. The epidermal barrier is crucial for the development of sensitization and elicitation of ACD. Factors that may influence the onset of sensitization in children are atopic dermatitis, skin barrier defects and intense or repetitive contact with allergens. Topical treatment of ACD is associated with cutaneous sensitization, although the prevalence is not high. ACD because of haptens in shoes or shin guards should be considered in cases of persistent foot eruptions or sharply defined dermatitis on the lower legs. Clinical polymorphism of contact dermatitis to clothing may cause difficulties in diagnosing textile dermatitis. Toys are another potentially source of hapten exposure in children, especially from toy-cosmetic products such as perfumes, lipstick and eye shadow. The most frequent contact allergens in children are metals, fragrances, preservatives, neomycin, rubber chemicals and more recently also colourings. It is very important to remember that ACD in young children is not rare, and should always be considered when children with recalcitrant eczema are encountered. Children should be patch-tested with a selection of allergens having the highest proportion of positive, relevant patch test reactions. The allergen exposure pattern differs between age groups and adolescents may also be exposed to occupational allergens. The purpose of this review is to alert the paediatrician and dermatologist of the frequency of ACD in young children and of the importance of performing patch tests in every case of chronic recurrent or therapy-resistant eczema in children.

The many faces of nickel allergy

Hypersensitivity reactions to nickel are one of the most common in the modern world. Nickel allergy prevalence is constantly growing in many countries and represents a major health and socioeconomic issue. Herein the current understanding on nickel allergy is summarized with a practical approach to the dermatologist, allergist, and general practitioner. The personal experience with some practical clinical cases of nickel dermatitis is shared. A special emphasis is put on the possible strategies for treatment and prevention of the disease.

The association between contact sensitization and atopic disease by linkage of a clinical database and a nationwide patient registry

BACKGROUND

Experimental studies have shown that individuals with atopic dermatitis are likely to have suppressed contact sensitivity secondary to their disease whereas some clinical and epidemiological studies have shown that individuals with atopic dermatitis might have a higher prevalence of contact sensitization than controls. The objective was to study the association between contact sensitization and, respectively, atopic dermatitis and asthma using clinical databases.

METHODS

Record linkage of two different registers was performed: (i) a tertiary hospital register of dermatitis patient's patch tested for contact sensitivity and (ii) the Danish National Patient Register containing nationwide hospital discharge diagnoses and outpatient contacts.

RESULTS

An inverse association was found between contact sensitization and, respectively, presumed severe atopic dermatitis (OR, 0.70; 95% CI, 0.61-0.81) and asthma (OR, 0.61; 95% CI, 0.42-0.90) when linkage was performed. Inverse associations were found for all groups of chemicals and metals except for sensitization to fragrances and topical drugs where positive associations were identified. A significant positive association between fragrance sensitization and presumed mild-moderate atopic dermatitis was also found when data from hospital register only were used, suggesting an overall higher prevalence of fragrance sensitization in patients with atopic dermatitis.

CONCLUSIONS

Our findings support that patients with severe atopic dermatitis and asthma have an overall lower prevalence of contact sensitization when compared with controls, whereas mild-to-moderate disease does not suppress contact sensitization. The prevalence of contact sensitization to fragrance chemicals was higher in patients with atopic dermatitis. Patients should be instructed to avoid scented moisturizers and products containing highly sensitizing substances.

Atopic dermatitis results in intrinsic barrier and immune abnormalities: implications for contact dermatitis

Atopic dermatitis (AD), as well as irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD), are common skin diseases. These diseases are characterized by skin inflammation mediated by activated innate immunity or acquired immune mechanisms. Although AD, ICD, and ACD can be encountered in pure forms by allergists and dermatologists, patients with AD often present with increased frequency of ICD and ACD. Although a disturbed barrier alone could potentiate immune reactivity in patients with AD through increased antigen penetration, additional immune mechanisms might explain the increased susceptibility of atopic patients to ICD and ACD. This review discusses cellular pathways associated with increased skin inflammation in all 3 conditions and presents mechanisms that might contribute to the increased rate of ICD and ACD in patients with AD.

Characterization of the polysensitized patient: a matched case-control study

BACKGROUND

Polysensitization ( >or= 3 contact allergies) may be regarded as a special entity in patients with contact allergies. However, this group of polysensitized patients is poorly characterized. Filaggrin mutations are associated with atopic eczema and lead to impaired skin barrier which may predispose to contact allergy. Therefore, it is of interest to consider atopic eczema and contact allergies, especially in patients with multiple allergies.

OBJECTIVE

To characterize polysensitized patients regarding occurrence, duration and course of dermatitis, and examine potential risk factors for polysensitization, including atopic eczema.

METHODS

A questionnaire case-control study of 562 polysensitized and 1124 single/double-sensitized individuals was performed.

RESULTS

The results show that 45% of polysensitized and 31% of single/double-sensitized patients had or had had atopic eczema, and atopic eczema was identified as a risk factor for polysensitization. Patients with leg ulcer constituted only a minor part of the polysensitized group and leg ulcers were not identified as a risk factor for polysensitization in this study. The influence of contact allergies on duration and course of disease diverged between the group of patients with atopic eczema and the group without atopic eczema.

CONCLUSION

Patients with atopic eczema were overrepresented in the group of polysensitized patients and polysensitized patients should be viewed in the light of occurrence or lack of atopic eczema.

Individual susceptibility to occupational contact dermatitis

Occupational Contact Dermatitis (OCD) is one of the most common work-related diseases. High risk occupations are in health care, hairdressing, food sector and metal industry. OCD tends to become chronic; persistent OCD often results in impaired quality of life and loss of work ability. The purpose of this article is to review the present knowledge on the factors which determine individual susceptibility to acquire OCD. Recent discoveries regarding genes involved in the skin barrier, inflammatory response and biotransformation of xenobiotics provide more insight in the individual susceptibility for OCD. Knowledge of the factors which predispose to OCD is useful in occupational health practice for the application of preventive measures and for career guidance for apprentices and workers in high risk occupations.

Filaggrin mutations and allergic contact sensitization

In this issue, Novak et al. (2008) provide evidence that filaggrin barrier defects might also predispose to allergic contact dermatitis by allowing greater penetration of chemical haptens. Their report provides a fresh perspective on the issues of contact allergy, nickel sensitization, and stratum corneum defects.

Breaking the cycle: how I manage difficult atopic dermatitis

This review summarizes the general approach and philosophy of managing difficult atopic dermatitis. There are as many regimens as there are physicians, but too many fail to provide patients with adequate relief. This leads to the wasteful alternative - an allergy-seeking behavior that makes caring for these patients even more complicated. If we, as dermatologists, provide rational counseling on prevention and skin care along with effective, stable, anti-inflammatory therapy, our patients may stop seeking irrational approaches. The new flood of information relating to epidermal barrier provides a basis for seeking and treating xerotic conditions earlier during infancy with the hope that the increasing problems with atopic dermatitis and asthma may be lessened with simple and safe measures.

Occupational contact dermatitis: etiology, prevalence, and resultant impairment/disability

Cutaneous irritant and allergic responses account for the vast majority of cases of occupational contact dermatitis (OCD). Although the pathophysiologic responses to these two different exposures are distinct, the clinical differentiation between chronic cumulative irritant contact dermatitis and allergic contact dermatitis can be difficult and frequently requires patch testing. This article reviews the recommended algorithms that clinicians should utilize to assess whether a worker suffers from OCD. The prevalence of OCD, its predisposing factors (both endogenous and exogenous), and prognosis are discussed in depth. Finally, issues surrounding the assessment of impairment and disability resulting from OCD are summarized.

Allergic contact dermatitis in children: should pattern of dermatitis determine referral? A retrospective study of 500 children tested between 1995 and 2004 in one U.K. centre

BACKGROUND

Allergic contact dermatitis (ACD) increases with age, and a prevalence of between 13.3% and 24.5% has been reported. Patch testing infants may be particularly difficult, and false-positive reactions may occur.

OBJECTIVES

The purpose of this retrospective study was to determine whether the site of primary dermatitis in children could predict a diagnosis of ACD. The current frequency of sensitization in children was also evaluated and the main sensitizing substances among children were verified.

METHODS

Between 1995 and 2004, 500 children were patch tested and entered on to the patch test database at Leeds General Infirmary. Analysis of the database included identifying the presenting patterns of eczema and reviewing the patch test results for each child.

RESULTS

Of the children, 133 (27%) had one or more positive patch test result. The effect of age on the likelihood of a positive patch test was highly significant (P < 0.001). Girls were significantly more likely to have a positive patch test compared with boys: odds ratio for a positive test 0.62 (95% confidence interval 0.41-0.95; P = 0.029). Type IV allergy to nickel (33%) was the most frequent finding. Reactions to fragrance mix (18%), cobalt (11%), mercapto chemicals, Myroxylon pereirae and p-phenylenediamine (each 8%) were the next most common. No statistical significance was found in the relationship between the site of primary dermatosis and a positive patch test result.

CONCLUSIONS

The pattern of presenting dermatitis in children should not determine referral for patch testing. Any child with persistent eczema should be referred for patch testing.

Simultaneous sodium lauryl sulphate testing improves the diagnostic validity of allergic patch tests. Results from a prospective multicentre study of the German Contact Dermatitis Research Group (Deutsche Kontaktallergie-Gruppe, DKG)

BACKGROUND

There is evidence that a higher skin susceptibility may induce nonspecific erythematous or weak positive reactions to contact allergens in patch testing.

OBJECTIVES

To evaluate whether simultaneous application of sodium lauryl sulphate (SLS) along with diagnostic patch tests with contact allergens can provide information regarding skin irritability which may help to discriminate allergic from nonspecific irritant reactions to contact allergens.

METHODS

Between July 2001 and June 2003, this prospective study collected patch test data of 5971 patients from 19 centres in Germany and Austria in the Information Network of Departments of Dermatology (IVDK). In addition to contact allergens (standard series and eight known 'problematic' allergens with a low reaction index and a high positivity ratio: 1,3-diphenylguanidine, amerchol L-101, benzalkonium chloride, benzoyl peroxide, cocamidopropyl betaine, octyl gallate, phenyl mercuric acetate and propylene glycol), patches with SLS 0.5% and 0.25% aq. were applied. Reactions to the allergens and to SLS were analysed at the IVDK data centre. The association between an erythematous or positive reaction to a certain allergen and an irritant reaction to SLS was assessed with logistic regression analysis, at the same time controlling for the influence of age and sex.

RESULTS

Of the 29 allergens of the standard series, 23 and 21 gave a higher percentage of nonspecific erythematous reactions in patients with an irritant reaction to 0.25% and 0.5% SLS, respectively, in comparison with SLS-negative patients. All eight 'problematic' allergens gave an increased percentage of nonspecific erythematous reactions. Similarly, 22 and 21 allergens of the standard series gave a higher percentage of positive allergic reactions in patients with an irritant reaction to 0.25% and 0.5% SLS, respectively, and seven of the eight 'problematic' allergens gave a higher percentage of positive allergic reactions (exception: octyl gallate). For most allergens, the markers of skin reaction (reaction index and positivity ratio) were worse in SLS-positive patients. Differences were more pronounced when testing with SLS 0.25% than with SLS 0.5%.

CONCLUSIONS

Because there is a convincing association between skin irritability (evaluated by SLS test) and the degree of skin reaction to contact allergens, the SLS test may help in deciding whether a doubtful erythematous or weakly 'positive' skin reaction should be interpreted as allergic or irritant.

Rice-induced enterocolitis in an infant: TH1/TH2 cellular hypersensitivity and absent IgE reactivity

BACKGROUND

Although food allergy is common in children, rice allergy is unusual in Western cultures.

OBJECTIVE

To report a case of T-cell-mediated rice intolerance in an 11-month-old girl.

METHODS

To evaluate the intolerance to rice in this patient, a graded rice food challenge was performed. To examine the immunologic reactivity to rice, in vitro lymphoproliferative responses and cytokine synthesis of rice-stimulated peripheral blood lymphocytes (PBLs) was performed. Subsequently, skin patch testing to rice and other foods was performed.

RESULTS

Allergy skin prick test results were negative for rice and positive for egg, milk, and soy. Specific IgE antibodies to rice, egg, peanut, wheat, walnut, codfish, milk, soybean, corn, shrimp, scallops, and clams were undetectable. Results of a single-blind rice food challenge were positive, manifested by emesis that persisted for more than an hour and required intravenous hydration. In vitro lymphoproliferation by the patient's PBLs to rice stimulation was positive. In addition, cytokine synthesis of interferon-gamma, interleukin 10 (IL-10), tumor necrosis factor a, and IL-5 by the patient's rice-stimulated PBLs was elevated, indicating a TH1/TH2 cell response to rice. Endoscopy revealed normal esophageal, gastric, and duodenal mucosa; a biopsy specimen revealed mild esophagitis. Duodenal explant T cells were initially established by stimulation with rice and IL-2. After a 2-day rest, the lymphocytes were restimulated with rice for 7 days and revealed increased interferon-gamma and IL-5 synthesis. Twenty billion colony forming units of Lactobacillus GG were added to the patient's diet twice daily. After 6 weeks, rice rechallenge resulted in emesis within 1 hour. Results of patch testing were positive to rice, wheat, and barley but negative to soy, which the patient tolerated on food challenge.

CONCLUSIONS

Although this patient did not demonstrate IgE antibody to rice, TH1/TH2 cell-mediated responses to rice were detected, and the patient experienced significant morbidity. Patch testing for gastrointestinal food allergies may be useful when the food specific IgE antibody is negative. Probiotic therapy in this patient did not ameliorate her sensitivity to rice, and food elimination remains the only reliable treatment for TH1/TH2-mediated food hypersensitivity.

Impaired responses of peripheral blood mononuclear cells to nickel in patients with nickel-allergic contact dermatitis and concomitant atopic dermatitis

BACKGROUND

Allergic contact dermatitis (ACD) is pathogenetically dependent on cell-mediated immune responses mediated by type 1 T lymphocytes. Atopic dermatitis (AD), in contrast, occurs as a result of sustained activation of type 2 subsets of T cells. Although atopic patients may become sensitized to various contact allergens, little is known about the influence of atopy on delayed-type hypersensitivity.

OBJECTIVES

To investigate the in vitro responses of peripheral blood mononuclear cells (PBMC) to nickel stimulation in groups of atopic and nonatopic patients with patch test-verified nickel ACD.

METHODS

Ten nonatopic patients with nickel ACD, 10 patients with nickel ACD and concomitant AD, 10 patients with AD but with no contact allergy, and 10 healthy persons participated in the study. PBMC were cultured in the presence or absence of nickel sulphate, phytohaemagglutinin (PHA) or tetanus toxoid (TT). [(3)H]thymidine incorporation was used to measure the rate of antigen-induced DNA synthesis and enzyme-linked immunosorbent assay was used to measure the production of interleukin (IL)-2 (type 1 cytokine) and IL-5 (type 2 cytokine).

RESULTS

Nickel-stimulated PBMC of nickel-allergic patients with AD proliferated significantly less and secreted significantly lower amounts of IL-2 than cells of nonatopic nickel-allergic patients. IL-5 production was also lower in the former group, although the difference was nonsignificant. Moreover, neither the nickel-specific DNA synthesis nor the cytokine production by PBMC of atopic nickel-allergic patients differed significantly from those of healthy control persons and AD patients without contact allergy. Proliferative and secretory responses of PBMC to PHA or TT stimulation differed nonsignificantly between the groups. Nickel-induced IL-2 production correlated well with IL-5 production in nickel-allergic patients regardless of their atopic status.

CONCLUSIONS

Our results indicate that PBMC of nickel-allergic patients with concomitant AD are characterized by impaired in vitro proliferative and secretory responses to the contact allergen nickel but not to the mitogen PHA or the recall antigen TT. The type 2 cytokine IL-5 may play a role in the development of ACD.

Patch-test reaction patterns in patients with a predisposition to atopic dermatitis

Patients with a predisposition to atopic dermatitis often need to be patch tested in order to detect possible contact sensitization. However, it is unknown whether immunologic or other peculiarities of atopic skin are related to altered patch-test reaction patterns. Our study was aimed at answering this question, because patch-test reaction patterns are of considerable practical importance in the reading and interpretation of patch tests. Therefore, we compared patterns of patch-test reactions in patients with a predisposition to atopic dermatitis and in control patients matched for sex, age, reason for testing and test centre. Patch-test results from 9 centres (2322 patients with a disposition to atopic dermatitis and 2126 matched controls) were evaluated retrospectively. All patients were tested with nickel sulfate, fragrance mix, potassium dichromate, lanolin alcohol, formaldehyde and mercury ammonium chloride. Patch tests applied for 1 day with readings on days 1, 2 and 3 were evaluated in order to cover the early phase of the reactions. Not unexpectedly, we found that, compared to the matched controls, patients with a predisposition to atopic dermatitis tended to have more doubtful and irritant reactions on day 1. As a new observation, it turned out that they had less reactions of crescendo pattern and more strong reactions on day 3. All these differences were slight/insignificant. A higher skin irritability in patients with a predisposition to atopic dermatitis is a likely explanation. In conclusion, standard methods for patch testing can be applied in patients with a predisposition to atopic dermatitis, but minor differences in reaction patterns should be considered.

Patch test results in 542 patients with suspected contact dermatitis in Turkey

In this retrospective study, patch test results of 542 patients (303 female and 239 male), referred to our clinic between June 1996 and July 1999, were evaluated. All patients were patch tested with 32 allergens of an extended European standard series, 140 patients were tested with supplemental series, and 246 patients with their own substances. 280 (51.7%) patients had 1 or more positive results but allergic contact dermatitis, according to clinical relevance, was diagnosed in only 190 (67.9%) of these. Nickel sulfate was the most frequent sensitizer (19.1%), followed by potassium dichromate (11.8%), palladium chloride (9.4%), cobalt chloride (8.5%), and thiuram mix (7.7%). Frequencies of contact allergy to fragrance mix (5.5%), balsam of Peru (Myroxylon Pereirae resin) (2%), quaternium-15 (0.6%), and Kathon CG (methylchloroisothiazolinone+methylisothiazolinone) (0.2%) were relatively low, while no positive reactions were obtained to paraben mix in any case. Current clinical relevance to the present dermatitis was most frequently seen with carba mix (96.2%), thiuram mix (95.2%) and potassium dichromate (78.1%), whereas this rate was low for nickel (37.5%). In 85.8% of patients with allergic contact dermatitis, the responsible allergen was detected by testing with the extended standard series alone (18.4% identified by testing with the additional 10 allergens), in 11.6% by testing with the patients' own substances, and in 2.6% by testing with the supplemental series. Occupational contact dermatitis was diagnosed in 77 of the patients with positive reactions (27.5%), most of these being construction workers and house painters who showed relevant sensitizations to potassium dichromate, cobalt chloride, thiuram mix and carba mix. There was no statistically significant difference in the total contact sensitization rate between atopics and non-atopics, but contact sensitivity to nickel sulfate and palladium chloride was significantly higher among atopics. MOAHL index in % was: 44.1/14.2/24.9/ 54.4/2.4. In conclusion, we believe that similar large series of patients would be helpful to delineate the exact profile of contact dermatitis in Turkey.

The role of patch testing for chemical and protein allergens in atopic dermatitis

Many patients who present for evaluation of allergic contact dermatitis have an atopic diathesis. Although the immunologic basis of atopic dermatitis differs from that of allergic contact dermatitis--and patients with atopic dermatitis are less easily sensitized under experimental conditions--atopic patients do develop allergic contact dermatitis, and patch testing is a valuable part of their medical care. Delayed (7-day) patch test readings are especially important in atopic patients to distinguish allergy from irritancy and to evaluate for steroid allergy. The utility of atopy patch tests to aeroallergens such as dust mite is increasingly recognized; aeroallergens may be the cause of a type of protein contact dermatitis.

Validity and ethics of the human 4-h patch test as an alternative method to assess acute skin irritation potential

For more than 50 years, the Draize rabbit skin irritation test has reigned supreme as the regulatory method of choice for the identification of skin irritant chemicals. To date no in vitro alternative test has been validated as an adequate replacement. However, one potential option, to test the endpoint of concern (skin irritation) in the species of concern (man) has been overlooked. The advent of predictive in vitro tools for the identification of substances corrosive to the skin has opened up the practical possibility of carrying out safe and ethical studies on small panels of humans. The human 4-h patch test has been developed to meet the needs of identifying chemical skin irritation potential, providing data which is inherently superior to that given by a surrogate model, such as the rabbit. This paper reviews in detail the present state of the human 4-h patch test, highlighting its advantages and noting its utility as the 'gold standard' on which to build future in vitro models.

Thoughts on sensitizers in a standard patch test series. The European Society of Contact Dermatitis

Patch testing is the predominant method of establishing contact allergy. The present patch test technique is the result of a continuous process of development and improvement since its first application in the late 19th century. The perfect patch test should give no false-positive and no false-negative reactions. The ideal patch test should also cause as few adverse reactions as possible, particularly no patch test sensitization. Even though the history and examination of a patient with suspected allergic contact dermatitis will give clues to possible sensitizers, it is not sufficient to patch test only with initially suspected sensitizers; unsuspected sensitizers used for patch testing frequently turn out to be the real cause of the dermatitis. Fortunately, a small number of substances are considered to account for the majority of delayed hypersensitivity reactions. Therefore, generally 20-25 test preparations consisting of chemically defined compounds, mixes of allergens, and natural and synthetic compounds, are grouped into a standard test series. The requirements to be fulfilled by a sensitizer in a standard patch test series are discussed in this article. A procedure of investigations is proposed before a sensitizer is included in a standard series.

Allergic contact dermatitis in children and adolescents

From a clinical point of view, the prevalence of allergic contact dermatitis (ACD) among children and adolescents seems to be low. However, many children have dermatitis, most often atopic dermatitis. In selected cases, ACD is suspected, and the child is tested. The question remains, whether the prevalence of ACD in children really is low or whether the possibility of ACD is not sufficiently considered. During the last decade, reports have appeared on series of children and adolescents with contact allergy and ACD. Few cases have been reported in infants, but the development of contact allergy and ACD increases with age. Most studies include selected groups of children and adolescents with suspected ACD. Few studies have examined unselected populations, and most consider only the prevalence of contact allergy without evaluating the clinical relevance, e.g., the prevalence of ACD. Furthermore, no follow-up studies exist. Therefore, the incidence and prevalence of contact allergy and ACD in children and adolescents is largely unknown.

Skin susceptibility of atopic individuals

The relevance of the irritant skin reaction of individuals with an atopic history (atopic dermatitis, rhinoconjunctivitis or atopic asthma) to sodium lauryl sulfate (SLS), a widely used irritant, is still controversial. The aim of this study was to evaluate transepidermal water loss (TEWL) as an indicator of stratum corneum integrity, before and after SLS patch testing, in various groups of atopic individuals with and without atopic dermatitis. 95 volunteers were divided into 4 groups: (1) individuals with active atopic dermatitis; (2) individuals with a history of atopic dermatitis but without active skin lesions; (3) individuals with rhinoconjunctivitis or atopic asthma without any symptoms at the time of testing; (4) healthy individuals serving as controls. The volunteers were patch-tested at the unaffected volar side of the forearm with aqueous SLS 0.5% for 48 h. TEWL was measured before application and after removal of the patch. Individuals with active atopic dermatitis showed a significantly higher TEWL value after SLS and a tendency to a higher basal TEWL as compared to the 3 other groups. There were no significant differences in TEWL between individuals who were classified as atopic but without active dermatitis, individuals with rhinoconjunctivitis or atopic asthma and healthy controls, either at the basal or at the post-SLS measurement. Enhanced skin susceptibility is only present in individuals with active dermatitis. The skin susceptibility of atopic individuals might therefore be increased as soon as the skin becomes eczematous, suggesting a reduced epidermal integrity probably caused by the endogenous atopy and/or respiratory allergens. When interpreting the atopy score in relation to skin susceptibility, the actual condition of the skin should hence be taken into consideration.

Contact dermatitis in children: 6 years experience (1992-1997)

We report the results of patch tests carried out over the last 6 years (1992 1997) on 141 children. This corresponds to 2.8% of the total patients who were patch tested in our Allergy Department (5,014). These 141 children were patch tested using the TRUE Test standard series and an additional allergen, metallic mercury. Allergens from the Chemotechnique medicaments, cosmetics, plants and shoe series were added in some. The most frequent localization of eczema was to the feet, face and hands and the most frequent suspected causes were costume jewelry, footwear, topical medicaments and cosmetics. The most frequent allergens, assessed by degree of relevance, were first, nickel, followed by cobalt, mercurials (thimerosal and metallic mercury), fragrance and rubber chemicals (naphthyl mix, mercapto mix, carba mix and PPD mix). 13 children, 18% of the total, between the ages of 12 and 14 years, showed positivities relevant to some occupation, i.e., metalworking, building, hairdressing, catering, etc. Once patch tests had been carried out and relevant positive patch tests assessed, the most frequent diagnoses were contact dermatitis 45%, atopic dermatitis 25%, juvenile plantar dermatitis 15%, and other diagnoses in the remaining 15%.

Epidermal Langerhans cell apoptosis is induced in vivo by nonanoic acid but not by sodium lauryl sulphate

Exposure to irritants may cause chronic irritant contact dermatitis (ICD), characterized by irregular epidermal thickening and a predominantly dermal mononuclear cell infiltrate. The mechanisms involved, and why only certain individuals are affected, are not clearly understood. Different irritants may trigger different cellular and molecular interactions between resident skin cells and recruited inflammatory cells. In some individuals these interactions may become self-perpetuating resulting in persistent inflammation in the absence of continued exposure. This study examined Langerhans cell (LC) density in clinically normal skin of 46 patients with chronic ICD and 10 healthy individuals, and compared the action of the two irritants nonanoic acid (NA) and sodium lauryl sulphate (SLS) on the LCs and keratinocytes of clinically normal skin in patients with chronic ICD. There was a higher number of LCs/mm basement membrane in patients compared with controls, although there was no difference in the number of dendrites/LC nor in dendrite length. SLS induced keratinocyte proliferation after 48 h exposure, had no effect on LC number or distribution, and induced keratinocyte apoptosis after 24 and 48 h exposure. In contrast, NA decreased keratinocyte proliferation after 24 h exposure but this returned to basal levels after 48 h, and induced epidermal cell apoptosis after only 6 h exposure. NA dramatically decreased LC number after 24 and 48 h exposure, which was accompanied by basal redistribution and decreased dendrite length. Most significantly, NA induced apoptosis in over half of the LCs present after 24 and 48 h exposure.

Managing the excited skin syndrome: patch testing hyperirritable skin

Inflammation-modulating phenomena (IMPs), humoral and cellular, fluctuate during the course of irritant and allergic contact dermatitis influencing irritability of the skin. The patch test procedure is a biological assay, a titration of responses of IMPs which can produce hyporeactivity or hyperirritability of the skin of patients who have dermatitis (PDs) and a single patch test is a 'snapshot' of the tempo of an evolving process. The excited skin syndrome (ESS) refers to hyperirritability from clinical and patch test dermatitis creating false-positive patch test reactions which are not reproducible when dermatitis and IMPs have subsided. During ESS, the threshold for irritancy decreases and irritant reactions increase. Patch test concentrations should be determined and ESS investigated in PDs having enhanced IMPs, not in 'normal' individuals, and if a patch test result is important to a patient the test should be performed more than once. Variable reproducibility is inherent in the patch test method, but ESS can be managed by appropriate testing and retesting, and search for relevance.