Mite-antigen-stimulated cytokine production by peripheral blood mononuclear cells of atopic dermatitis patients with positive mite patch tests

To investigate possible involvement of Th1-type immunoreaction in the development of skin lesions of atopic dermatitis (AD), we measured mite-antigen-stimulated production of IL-2, IL-4 and IFN-γ, using peripheral blood mononuclear cells (PBMC) obtained from 23 patients with AD who developed positive patch test reactions to house dust mite antigens extracted from Dermatophagoides pteronyssinus (Dp). Incubation of these PBMC with the Dp antigen for 72 h produced marked secretion of IL-2 and IFN-γ, but not IL-4, indicating that Dp-specific T cells were found in these patients' circulating peripheral blood and were capable of producing IL-2 and IFN-γ, known as major mediators of the delayed-type allergic reaction. Our study suggests that Thl-type cells may be involved in the development of skin lesions of AD patients with positive patch test reactions to house dust mite antigen.     

Correlation between laser Doppler perfusion imaging and visual scoring of patch test sites in subjects with experimentally induced allergic and irritant contact reactions

Purpose: To compare laser Doppler perfusion imaging (LDPI) measurements in experimentally induced allergic contact reactions and irritant contact reactions. The degree of correlation between visual scores and LDPI measurements was also studied.
Methods: Fifteen patients with known contact allergy to nickel or fragrance were patch tested with nickel sulfate 5% pet., fragrance mix 8% pet., sodium lauryl sulfate (SLS) 0.5% pet., SLS 1.0% pet. and two empty control chambers. Visual readings and LDPI measurements were taken at 0, 48 and 96 h.
Results: There was a positive correlation between visual scores and LDPI measurement in the nickel sulfate and fragrance mix patch test sites. However, no correlation between visual scores and LDPI measurements was seen in the SLS 0.5% and SLS 1.0% patch test sites. There was no significant difference ( P =0.125) in LDPI measurements between contact-allergic reactions and contact-irritant reactions.
Conclusion: LDPI correlates with visual scoring in contact-allergic reactions, but not in irritant reactions. LDPI is not useful in distinguishing between allergic and irritant reactions.     

Alterations of epidermal lectin binding sites in acute contact dermatitis

We investigated alterations of epidermal lectin binding sites, as well as of pemphigus and bullous pemphigoid antigens, in 28 human patch test reactions, both allergic (nickel, formaldehyde, N,N'-1,3-dimethylbutyl-N'-phenylenediamine) and irritant (sodium lauryl sulfate). The epidermal reactivity to a panel of lectins and human antisera to pemphigus vulgaris and bullous pemphigoid antigens was compared with samples obtained from normal skin and from skin under tape occlusion. We observed selective perturbations of lectin and antibody binding in acute contact dermatitis, whether allergic or irritant. The main findings were a loss of terminal sialic acids and longer bi- and triantennary mannosyl residues as well as a loss of pemphigus vulgaris antigen. The only difference between allergic and irritant patch test reactions was in topography of loss of WGA binding sites: in the former, it was most pronounced in the lower and middle epidermis, whereas in the latter it was seen in the uppermost subcorneal layers. Our findings support a common pathway of cell membrane alterations of keratinocytes in acute contact dermatitis.     

Occupational dermatoses from epoxy resin compounds

This study comprises 40 patients with skin disorders from current or previous occupational exposure to epoxy resin compounds (ERC) during 1984-1988. ERCs were the 3rd most common cause (32 of 264 cases: 12.1%) of currently relevant allergic contact dermatitis: 23 cases from epoxy resins based on the diglycidyl ether of bisphenol A (DGEBA-ERs), 5 from reactive diluents, 1 from amine hardeners (DETA), and 3 from epoxy acrylates. 2 cases (0.8%) of irritant contact dermatitis were due to ERCs. Methyl hexahydrophthalic anhydride (MHHPA, an epoxy hardener) caused 1 case of contact urticaria. Previously relevant occupational allergic contact dermatitis from DGEBA-ERs was detected in 5 cases. On patch testing, ERC allergens gave the following positive reactions: epoxy resin of the standard series in 35 cases (4.0% of 870 tested), epoxy reactive diluents in 10 (7.1% of 140), cycloaliphatic epoxy resins in 4 (11.1% of 36), epoxy acrylates in 4 (4.5% of 88), and amine compounds commonly used as epoxy hardeners in 17. Despite extensive patch test series, testing with patients' own ERCs remains important.     

Interferon-γ secreted from peripheral blood mononuclear cells as a possible diagnostic marker for allergic contact dermatitis to gold

10% of patch-tested patients have a positive reaction to gold. Most lack clinical symptoms, but allergic contact dermatitis (ACD) to gold is increasing. In this study, 77 dermatological outpatients were divided into 3 groups depending on epicutaneous patch test outcomes: a group positive to gold (EPI+), a group negative to gold (EPI−), and a group with irritant reactions to gold (EPI-IR). Lymphocytes were stimulated in vitro with gold sodium thiosulfate. Proliferation was assessed using the lymphocyte transformation test (LTT), and cytokine secretion was assessed using a multibead array (Luminex^®; Linco Research Inc., St. Charles, MO, USA), in order to evaluate whether an in vitro method with high diagnostic accuracy could be devised. The EPI+ group showed a significantly increased secretion of interferon (IFN)-γ, interleukin (IL)-2, and IL-13 and also showed a significantly higher stimulation indexes for LTT, compared to the other 2 subject groups. Sensitivity and specificity were calculated for all methods individually and combined, but IFN-γ assessment alone was the most accurate method for identifying ACD to gold, with sensitivity and specificity of 81.8% and 82.1%, respectively. This method also identified 87.5% of the EPI-IR subjects as non-allergic. Therefore, assessment of secretion of IFN-γ should be a valuable complement to patch test for diagnosing gold allergy.     

Contact allergy to phenol-formaldehyde resins

Adverse reactions to phenol-formaldehyde resins include depigmentation, irritant dermatitis, chemical burns and allergic contact dermatitis. Allergic contact dermatitis from phenol-formaldehyde resin has mainly been ascribed to resins based on paratertiary-butyl phenol and formaldehyde, and such a resin is included in the ICDRG standard patch test series. When 1220 patients were patch tested with this resin as well as with 2 other phenol-formaldehyde resins, based on phenol and formaldehyde, 26 patients were positive to at least 1 resin. The figures for positive reactions to paratertiary-butyl phenol-formaldehyde resin and the 2 other resins were 0.8%, 1.0% and 3.0% (440 tested subjects), respectively. Therefore, a battery of phenol-formaldehyde resins should be used for screening purposes, since patch testing with the paratertiary-butyl phenol-formaldehyde resin is not sufficient to identify patients with contact allergy to phenol-formaldehyde resins. Several of the 26 patients were patch tested with the basic substances phenol, formaldehyde and paratertiary-butyl phenol, but only 1 positive reaction to formaldehyde was noted. The sensitizing capacity of 2-methylol phenol, 4-methylol phenol and 2,4,6-trimethylol phenol, all 3 compounds being possible ingredients of resins based on phenol and formaldehyde, was demonstrated; 5 of 14 resin positive patients reacted to at least 1 of these methylol phenols.     

Patch testing with methyldibromo glutaronitrile, a multicentre study within the EECDRG

Contact allergy to and allergic contact dermatitis from methyldibromo glutaronitrile (MDBGN) have frequently been reported. As there has been no agreement on which MDBGN test preparation to use, a study was initiated to help determine the optimal patch test preparation for MDBGN. 2661 consecutively patch tested patients at 11 test clinics representing 9 European countries participated. Petrolatum preparations with MDBGN at 1.0%, 0.5%, 0.3% and 0.1% were inserted in the standard series. Contact allergy rates were noted in the range 4.4-1.1% following decreasing test concentrations. Reactions not fulfilling all criteria to be classified as allergic reactions could represent either weak allergic or irritant reactions, and such reactions were noted in the range 8.2-0.5% with decreasing concentrations. A significant number of these reactions represented weak allergic reactions, as allergic reactions were obtained to higher patch test concentrations in the same individual. Morphologically irritant reactions were noted only for the highest test concentrations. In summary, the contact allergy rates and frequencies of doubtful and irritant reactions vary with the patch test concentration. The final decision on patch test concentration for MDBGN should not only rely on these factors but also include information on patch test concentrations required to diagnose individual cases with allergic contact dermatitis from MDBGN as well as results of repeated open application tests.     

Lymphocyte subsets and Langerhans cells in allergic and irritant patch test reactions: histometric studies

This study has attempted to distinguish between allergic and irritant reactions to patch tests by semiquantitative histological methods. The extent of perivascular chronic inflammatory infiltrate at 72 h in irritant patch test reactions to sodium lauryl sulphate was shown to be small and very consistent, whereas in allergic reactions to nickel sulphate it was generally larger and more variable in size (p less than 0.02). The two major lymphocyte subsets (T4 and T8) were randomly intermixed in both types of reaction and formed the major component of both the perivascular and diffuse dermal infiltrate, without any evidence of selective migration. The T4:T8 ratios were similar in focal and diffuse infiltrates. The number of T6 dendritic (putative Langerhans) cells in the epidermis (per mm inner epidermal length) was usually greatly reduced in irritant reactions (5-16 mm-1, mean 10 mm-1) but remained within normal limits in allergic reactions (6-33 mm-1, mean 21 mm-1) (p less than 0.001). Comparable results were seen with other irritants (mercuric chloride and benzalkonium chloride) and other allergens (neomycin sulphate, ethylene diamine and potassium dichromate). In additional experiments, pairs of biopsies were taken from the reaction and from adjacent unaffected skin. The T6 cell density in the epidermis did not significantly differ between allergic reactions and control skin. By contrast, the irritant reactions had fewer T6 cells than the control skin (p less than 0.001).     

ETAF/Interleukin-1 and epidermal lymphocyte chemotactic factor in epidermis overlying an irritant patch test

We have previously demonstrated that the epidermal content of the lymphocyte activating peptide ETAF/IL-1 and lymphocyte chemotactic factor (ELCF) increases during the development of a cell-mediated immune reaction, represented either by the tuberculin skin reaction or by a positive patch test in patients with contact allergy. The present study describes the epidermal content of these mediators during an irritant patch test reaction. The results show that ELCF, but not ETAF/IL-1, is significantly increased in the epidermis of an irritant patch test with 3% SLS or 5% croton oil, irrespective of the intensity of the clinical patch test reaction. We observed that simple occlusion of epidermis did not induce ELCF activity in healthy persons, whereas patients with previous or current eczema had a significant release of ELCF following such occlusion. These results seem to indicate that there exist important functional differences between allergic and irritant patch test reactions with respect to the presence of lymphocyte activating signals in epidermis.     

Nickel sulphate and epoxy resin: differences in iron status and glutathione redox ratio at the time of patch testing

The reactive patch test reaction is a useful model to characterize oxidative stress in acute allergic contact dermatitis. This model was used to study oxidative stress in the skin of individuals allergic to nickel and epoxy resin. The study included six and five patients, respectively, whose skin was simultaneously biopsied from a positive patch test site and from an apparently healthy area. The biopsies were homogenized and used for determination of iron content, unbound iron binding capacity, diene conjugate levels, and glutathione redox ratio. A positive test reaction to 5% nickel sulphate was accompanied by 2.5-fold increase in iron level as compared to apparently healthy skin (P<0.1). The percentage saturation of iron-binding capacity and the glutathione redox ratio were significantly increased (P<0.01 and P<0.05, respectively). Reactive patch test responses to 1% epoxy resin were not accompanied by clear alterations in iron status or glutathione redox ratio. Our investigation showed that apart from oxidative burst caused by accumulation of inflammatory cells, hapten properties might also influence the oxidative stress status of the skin. The high incidence of nickel allergy may be attributed, at least in part, to the influence of nickel ions on the glutathione redox ratio and iron status of the skin.     

Sodium lauryl sulfate irritant patch tests: Degree of inflammation at various times

Irritant reactions were induced on the forearms of 10 normal subjects with 10% aqueous sodium lauryl sulfate under patch test occlusion for 24 h. Test sites were observed at 24, 26, 28, 30, 48, 72 and 96 h and the degree of inflammation recorded. Inflammation was most prominent at 28 h and decreased in intensity over the time course of the study. Inflammation at 48 and 72 h was similar to when patches were removed. This suggests that inflammatory responses in skin for at least certain irritants like sodium lauryl sulfate do slowly decrease in intensity after 48 h. However, the inflammatory response may initially accelerate after patch test removal and remain intense for at least 48 h. Fading of irritant reactions by 48 or 72 h may not reliably distinguish irritant from allergic patch test reactions. This does not refute the usefulness of a delayed (96 h) reading since inflammation from sodium lauryl sulfate had decreased significantly by this time.     

Occupational dermatitis in a prefabrication construction factory

In a field study of Occupational Dermatoses in a prefabrication construction factory, 272 workers were interviewed, examined and patch tested to chromate, cobalt, nickel, rubber mixes, epoxy resin, melamine formaldehyde and conplasts. The prevalence occupational dermatitis was 14% (38/272); 57% (22/38) were irritant dermatitis from cement; 39.5% (15/38) were allergic contact dermatitis from cement (2 with concomitant rubber glove allergy); and 2.5% (1/38) were allergic to rubber chemicals in gloves. The overall prevalence of chromate sensitivity was 8.5% (23/272), with the highest rate from the concreting bays of the factory. The rate was unrelated to the duration of workers'engagement in construction work. 34.8% (8/23) had asymptomatic chromate allergy. The prevalence of cobalt reactions was 17.4% (4/23) and all were associated with chromate allergy.     

Another look at seasonal variation in patch test results. A multifactorial analysis of surveillance data of the IVDK. Information Network of Departments of Dermatology

There is conflicting evidence concerning seasonal variability of patch test results and no evidence concerning the influence of season on weak-positive, possibly false-positive, irritant reactions, which was analysed in the present study. Data collected in the German Information Network of Departments of Dermatology (IVDK) 1992 to 1997 were combined with external environmental data on temperature and absolute humidity in Germany, and bivariate as well as logistic regression analyses performed concerning the association between reactivity to selected allergens and air temperature and absolute humidity on the respective days of patch testing. Between 39,239 and 41,629 patients had been tested with the 4 allergens considered here. Only formaldehyde exhibited a distinct increase in questionable or irritant as well as weak-positive reactions associated with dry, cold weather. Methylchloroisothiazolinone/methylisothiazolinone and lanolin alcohol showed only a weak, and epoxy resin no, association with climatic conditions. The results indicate that weak-positive reactions, at least to formaldehyde as a prototype of an allergen which is at the same time a marginal irritant, may sometimes be irritant rather than allergic. Patients showing these should be re-tested to improve the poor reproducibilty observed with this allergen.     

Contact allergy to epoxy resin: risk occupations and consequences

Background. Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown. Objectives. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work‐related consequences. Patients/methods. The dataset comprised 20 808 consecutive dermatitis patients patch tested during 2005–2009. All patients with an epoxy resin‐positive patch test were sent a questionnaire. Results. A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization to epoxy resin remained stable over the study period. Of the patients with an epoxy resin‐positive patch test, 71% returned a questionnaire; 95 patients had worked with epoxy resin in the occupational setting, and, of these, one‐third did not use protective gloves and only 50.5% (48) had participated in an educational programme. Conclusion. The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required.     

The association between ambient air conditions (temperature and absolute humidity), irritant sodium lauryl sulfate patch test reactions and patch test reactivity to standard allergens

To support the decision as to whether erythematous patch test reactions to allergens are irritant or allergic, sodium lauryl sulfate (SLS, 0.5% in water) has been added to the standard patch tests since July 1996 in the Dortmund Department of Dermatology. Data on 1600 patients patch tested up until June 2001, as well as standardized data on ambient temperature and humidity obtained by the German Meteorological Service, were included in a logistic regression analysis taking age, sex and atopy as potential confounders into account. The pattern of association was heterogeneous: while doubtful reactions to nickel sulfate were significantly associated with dry/cold weather conditions, but not with SLS reactivity, the opposite was observed for lanolin alcohol, benzocaine and Myroxylon pereirae resin (balsam of Peru). Doubtful reactions to other allergens, namely formaldehyde, fragrance mix or p-phenylenediamine, were associated with both factors. For several other allergens of the standard series, no distinct, significant pattern could be discerned. In conclusion, meteorological conditions and SLS reactivity independently contribute information on individual irritability at the time of patch testing, and both should be considered.     

Occupational dermatoses from exposure to epoxy resin compounds in a ski factory

Of 22 workers in a ski factory, occupational allergic contact dermatitis was found in 8. 6 were sensitive to epoxy resin compounds, i.e. epoxy resins, hardeners or diluents. I to cobalt in glass-fiber reinforcements, and I to formaldehyde in a urea–formaldehyde glue and a lacquer. 4 workers had irritant contact dermatitis from epoxy resin compounds, lacquers, sanding dust. or glass-fiber dust. 3 had contact allergy from a new sensitizer, diethyleneglycol diglycidyl ether, in a reactive diluent. Immediate transfer of workers sensitized to epoxy resin from epoxy exposure prevents aggravation of their dermatitis and broadening of the sensitization to epoxy hardeners, diluents and other compounds.     

Occupational contact allergy to unsaturated polyester resin cements

6 men contracted occupational allergic contact dermatitis from unsaturated polyester (UP) cements. 4 of the men were employed in ear repair painting and the remaining 2 in mold manufacturing. The exposure time to UP cements ranged from 6 to 32 years before onset of skin symptoms. All patients had eczema on their hands: in addition. 4 had skin symptoms on airborne areas, i.e., wrists, neck and face. All 6 patients developed allergic reactions when patch tested with UP resin at 0.5–10% in petrolatum (pet.). None of the tested patients reacted to auxiliary or cross-linking chemicals of the cements. Diethylene glycol maleate (DGM) was purified and identified from the UP resin of a cement. 1 patient reacting to UP resin was also patch test positive to DGM and he produced an allergic reaction to DGM down to a concentration of 0.0032% pet. DGM was found in both uncured and cured UP resin. None of the patients could continue their work with UP cements after their sensitization.     

Skin irritancy from nonanoic acid

100 hospitalized patients with skin disease were patch tested with graded dilutions of nonanoic acid (NON), sodium lauryl sulfate (SLS) and benzalkonium chloride (BENZ), Smooth dose-response curves were obtained. The concentration needed to produce a discernible irritant reaction in 50% of the population (ID₅₀) was found to be lower in cases of irritant than of allergic contact dermatitis; this finding warrants further study. Björnberg's observation that it is not possible to predict the strength of the reaction to one irritant by knowing the strength of the reaction to another was confirmed. Benzalkonium chloride caused a high frequency of pustular and/or billions reactions with scarring as a sequela. It is suggested that this irritant could be replaced by nonanoic acid in experimental studies of topical irritancy, since the test reactions from nonanoic acid were reproducible, easy to read and left no staining or scarring.     

Formaldehyde concentration in diagnostic patch testing: comparison of 1% with 2%

Exposure to formaldehyde is common from both consumer products and industry. The reliability of the patch test is essential for the diagnosis of formaldehyde allergy as it is difficult to suspect from the patient's history. The recommended formaldehyde patch test concentration has been reduced over the last decades from 4–5% to 2% and is currently 1%. The changes have not been based upon formal studies, but driven by an intention to reduce irritancy and false-positive results. The aim of the present study was prospectively to compare the outcome of simultaneous testing with formaldehyde 1% and 2% in consecutively patch-tested patients, with respect to frequency of positive patch test reactions, strength of patch test reactions to different formaldehyde test concentrations, irritancy and relevance. The study included 3734 consecutively patch tested patients. 121 gave a positive reaction to 1% and/or 2% formaldehyde in water. There was no statistically significant difference between 1 and 2% with respect to allergic reactions, but 2% gave significantly more irritant reactions. Doubtful, positive and follicular reactions at day (D) 2 frequently developed into true positive reactions at D 3 to 4. Reading at D 7 gave few additional positive cases compared to D 3/4. Problems related to relevance are discussed. Based on present knowledge, a 1% patch test concentration for formaldehyde is recommended.     

Ultrasound for assessment of allergic and irritant patch test reactions

The oedema formation of patch test reactions was quantified by high-frequency ultrasound measurement of skin thickness. Patch testing with nickel sulphate, nickel chloride and sodium lauryl sulphate 1, 2, 5 and 10% was performed in 12 individuals with known nickel allergy. Oedema was greater in allergic than in irritant reactions similar in strength according to the clinical reading. In allergic reactions, the oedema appeared more transcutaneous, while in irritant reactions, more superficial. For differentiation of the 2 types of reaction, application of substances for a 24-h period with measurements the following day is preferable. For rating of allergic and irritant reactions, 48 h of application is preferable with measurements performed on the day patches are removed.