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Infants (n = 35) with digestive symptom were investigated for diagnosis of cow's milk allergy (CMA). Milk atopy patch tests (APTs) were positive in 19 of 24 CMA versus 1 of 11 in non-CMA patients (P <.001). This sensitivity (79%) and specificity (91%) suggest that the APT could improve the detection of conditions related to CMA.
From the large number of substances used in perfumes it is difficult and tedious to identify the allergen in a specific case of dermatitis. Many substances are both irritants and sensitizers. Based on personal experience, a list has been prepared of potential sensitizers, their concentrations and diluents suitable for patch testing.
The possible correlation of clinically recorded test reactions and morphological changes at electron microscopic resolution in human subjects allergic to chromate (CrVI) was investigated. The effect of simple occlusion and of vehicles, e.g. distilled water, an alkaline buffer, and petrolatum was also studied 72 hours after application. The results indicate that even simple occlusion causes reactive changes in living epidermal cells. These changes become conspicuous in occlusion with distilled water, more pronounced with petrolatum, and were destructive in the case of the alkaline buffer. Chromate solutions produced varying degress of morphological change but were less pronounced in a vehicle of distilled water, compared with the changes seen when the chromate was combined with the alkaline buffer. Destructive cellular changes were observed in the electron microscope even in sections from test ares where no macroscopical reactions were recorded. When the clinical evaluation of hypersensitivity was done 72 hours after the application of the patch test the morphological changes were too advanced to provide specific pathognomonic information.
Evaluation of the irritant potential of new products or ingredients prior to human testing is generally performed in vivo on animals. However, according to the 6th amendment and following updates of the European Community directive on cosmetic products (93/35/EEC), animal testing will be banned when suitable substitutes will be available. To know whether in vitro tests for assessment of skin irritancy provide results approaching human conditions, comparisons have to be made between data deriving from in vitro tests and skin response in humans. The aim of our study was to assess the validity of the monolayer culture system of normal human keratinocytes as a model for the evaluation of the irritant effects of detergents, by comparing in vitro cell culture data to in vivo acute skin irritancy effects of cocamidopropyl betaine (CAPB), an amphoteric compound, Tween 20 (TW20) (polysorbate 20) and Tween 80 (TW80) (polysorbate 80), representing nonionic compounds, applied to the skin of 24 healthy volunteers at a concentration similar to that employed in commercial products. As parameters for cytotoxicity, cell proliferation, cell membrane integrity and cell metabolism were assessed by cell counts, thymidine incorporation, MTT conversion, and Neutral Red uptake. In order to increase the sensitivity of the in vivo evaluation, bioengineering methods for assessment of the effects of test products on the skin were employed. Whereas all 4 in vitro methods ranked the tensides according to their toxicity in the following order: CAPB>SLS>TW20>TW80, both in vivo methods agreed in identifying SLS as the most irritating substance. Moreover, as compared with the irritation potential on human skin, all 4 in vitro tests overestimated the toxicity of CAPB. This suggests that the keratinocyte monolayer cell culture technique cannot directly replace in vivo methods, and that data obtained by this method should be interpreted cautiously.
We report a confirmed case of intraoral contact mucositis secondary to nickel dental alloy hypersensitivity. The lesion resolved after removal of the offending prosthesis. The patient responded negatively to dermatologic patch tests, but a positive intraoral rechallenge confirmed the mucositis diagnosis. A nonreactive, gold alloy prosthesis was inserted for a successful result.
BACKGROUND: While immediate-type clinical reactions to food can quite easily be identified by history or measurement of specific IgE in combination with positive oral food challenges, the evaluation of food allergy in the absence of immediate clinical reactions still presents diagnostic difficulties--particularly in children with atopic dermatitis. The objective of this study was to evaluate the diagnostic value of the atopy patch test (APT) with regard to late-phase reactions observed in double-blind, placebo-controlled food challenges with cow's milk, hen's egg, wheat, and soybean. METHODS: We investigated 75 children (median age 2.1 years) with suspected food allergy by double-blind, placebo-controlled food challenges, specific IgE in serum, skin prick test, and APT. Of the subjects, 69/75 suffered from atopic dermatitis. RESULTS: Of 209 oral challenges, 133 were performed with allergen and 76 with placebo. We assessed 77/133 allergen and 2/76 placebo challenges as positive. In 66 of 77 (86%) positive oral challenges, specific IgE in serum to the corresponding allergen was positive; in 64/77 (83%) the skin prick test, and in 42/77 (55%) the APT was positive. While immediate-type reactions were associated with positive skin prick test and proof of specific IgE in serum, late-phase clinical reactions were associated with a positive APT (sensitivity 76%, specificity 95%). CONCLUSIONS: The APT seems to be a valuable additional tool in the diagnostic work-up of food allergy in children with atopic dermatitis - especially with regard to late-phase clinical reactions. The APT may help to prevent unnecessary restrictive diets which may be the consequence of misjudging late reactions by clinical assessment alone.
From July 1996 through June 1998, the North American Contact Dermatitis Group evaluated 318 patients for suspected contact dermatitis by patch testing simultaneously with Finn Chambers and the T.R.U.E. Test allergen system. Discrepancies between the two systems were found in some of the results, particularly with fragrance and rubber allergens. These results suggest that positive reactions to fragrance, thiuram, and carba mix allergens may be missed if the T.R.U.E. Test is used alone.
OBJECTIVE: The study was designed to evaluate the atopy patch test (APT) and the late-phase reaction (LPR) after intracutaneous allergen injection as models for the study of allergic inflammation in atopic eczema. METHODS: Immunocytochemistry was used to analyze skin biopsy specimens from sites of APTs and LPRs at 2 and 24 hours and to compare these with lesional and nonlesional skin of patients with atopic eczema. RESULTS: A lack of neutrophil infiltration in specimens from both the APT and lesional skin sites was observed, whereas neutrophils were abundantly present in the specimens from LPR sites. With double-staining techniques it was demonstrated that the few neutrophils present in specimens from APT sites and in lesional skin were mostly located in intravascular areas, whereas in the LPR specimens they were located predominantly in extravascular areas. Eosinophils infiltrated at an earlier time point in the LPR as compared with the APT. Furthermore, there was a decrease of intact mast cells in the LPR site compared with the APT sites and lesional skin. No significant difference in T-cell number was observed between the two tests. Upregulation of E-selectin expression on endothelial cells occurred at an earlier time point in the LPR as compared with the APT. CONCLUSION: There are important differences in cellular infiltrate between the APT and the LPR. The close macroscopic and microscopic similarities between the specimens from APT sites and lesional skin of patients with atopic eczema support the argument that the APT is a more valid in vivo model with which to study allergic inflammation in atopic eczema than the LPR.
5 cases of allergic contact dermatitis from rubber gloves were investigated by our recommended procedures using a combination of patch testing in patients and chemical analysis of causative rubber products by gas chromatography (GC) and high-performance liquid chromatography (HPLC). We previously confirmed that zinc ethylphenyldithiocarbamate (ZEPC), a dithiocarbamae-type accelerator (DTC), was causative in a case of allergic contact dermatitis from rubber work gloves. Subsequently, we have clarified that DTCs such as zinc dimethyldithiocarbamate (ZDMC), zinc diethyldithiocarbamate (ZDEC) and zinc dibutyldithiocarbamate (ZDBC) and amines such as dimethylamine (DMA), diethylamine (DEA) and piperidine (PIP) were also causative in cases from surgical rubber gloves. Thus, our investigative studies revealed that, although thiurams have been taken much more notice of as allergenic compounds than their corresponding DTCs and amines, not only DTCs such as ZDMC, ZDEC, ZDBC and ZEPC, but also amines such as DMA, DEA and PIP were noteworthy causative candidates of allergic contact dermatitis from rubber gloves.
The use of computer technology to store, retrieve, and analyze patient data is not new. This article reviews the use of computerized data bases in patch test result record keeping. Efforts of the North American Contact Dermatitis Group serve as an example of how to create, manage, and apply these data.
23 patients who had used silver sulfadiazine cream were patch tested. No reactions to the active principle occurred but 2 vehicle components, cetyl alcohol and propylene glycol, were positive. No sulfonamide-sensitive subject reacted to silver sulfadiazine. There is no evidence that silver sulfadiazine has a contact sensitizing potential or that it is contra-indicated for patients with a history of sulfonamide hypersensitivity.
Nearly all effective, commercially available preservatives possess skin sensitization potential. This manuscript describes a program of diagnostic patch and practical use testing of consumer products that contained Kathon CG, a relatively new biocide. A series of threshold diagnostic patch tests demonstrated that the minimal elicitation concentration in occluded patch testing of allergic subjects considerably exceeded the concentrations of the biocide typically present in normal diluted use of the test products. Use testing further confirmed a threshold exposure for eliciting allergic reactions. It showed that even subjects who have delayed contact hypersensitivity to Kathon CG used rinse-off personal care products preserved with this agent without experiencing elicitation of these allergies.
BACKGROUND: Atopic dermatitis is commonly associated with food allergy. In addition to skin prick tests (SPTs) and measurements of specific IgE levels, the atopy patch test (APT) has recently been introduced into the diagnostic procedure for food allergy. OBJECTIVE: Our aim was to evaluate whether a combination of allergologic tests could improve the prognostic value of the individual tests for positive food challenge results. We hypothesized that the combination of a positive APT result plus proof of specific IgE, a positive SPT result, or both would render double-blind, placebo-controlled, food challenges unnecessary. METHODS: One hundred seventy-three double-blind, placebo-controlled, food challenges were performed in 98 children (median age, 13 months) with atopic dermatitis. All children were subjected to SPTs, APTs, and determination of specific IgE. Sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS: Ninety-five (55%) of 173 oral provocations were assessed as positive. For evaluating suspected cow's milk (CM) allergy, the APT was the best single predictive test (positive predictive value [PPV], 95%), and the combination of a positive APT result with evidence of specific IgE or an APT result together with a positive skin prick test response optimized the PPV to 100%. For hen's egg (HE) allergy, the APT was also the best single predictive test (PPV, 94%). The combination of 2 or more tests did not exceed the APT's predictive value. In both CM and HE challenges, the predictability of oral challenges depended on the level of specific IgE. For wheat allergy, the APT proved to be the most reliable test, and the PPV of 94% could not be improved by a combination with other allergologic tests. CONCLUSION: The combination of positive APT results and measurement of levels of specific IgE (CM, > or = 0.35 kU/L; HE, > or = 17.5 kU/L) makes double-blind, placebo-controlled, food challenges superfluous for suspected CM and HE allergy.
Cellular responses in allergic and irritant contact dermatitis were analysed in situ using an immunohistochemical double staining technique with the aim of uncovering phenotypical differences of diagnostic importance. Allergic and irritant patch test reactions were elicited in 9 individuals using the Finn chamber technique. Thirty-nine skin biopsies from these reactions and from petrolatum controls were obtained 4 to 20 days after the test applications. Cell infiltrates were present throughout the observation period in both allergic and irritant reactions, but were usually greater in the former. In both types of reaction, anti-Leu 3a reactive cells predominated over anti-Leu 2a reactive cells. HLA-DR expression on keratinocytes was found in 9 of 14 allergic reactions, but not in irritant reactions or control areas. HLA-DQ antigens were not detected on keratinocytes. The presence of HLA-DR antigens on keratinocytes may reflect an immunological response of the allergic reactions, and thus be of diagnostic relevance.
A group of 853 construction industry workers exposed to irritants and allergens (mainly cement, lime, sand, water, lubricants and antiadhesive oils and a control group of 74 subjects (sawers) underwent patch tests after Jadassohn--Bloch with seven allergens most common in the construction industry working environment (compounds of chromium, nickel and cobalt, turpentine and three rubber allergens--mercantobenzothiazole, thiocarbamoyl and diphenylguanidine). Allergy was found in 25.5% of the construction industry workers, in this 7.7% were those with eczema and dermatitis, 17.8%--those with latent allergy (in 12.2% allergy was accompanied by dermatoses of non-allergic etiology, 5.6% construction workers no skin changes). The highest number of skin positive tests was that with chromium (22.4% of affected workers) and cobalt (12.4%). Most susceptible to allergy were: painters, bricklayers, carpenters, joiners, reinforcing concretors, terrazers, concretors, electricians, smiths and reinforcers. In addition, allergy was found to be dependent on age and length of employment.
BACKGROUND: Allergic contact sensitization to 'para amino' compounds is frequent and the spectrum of cross-reactivity between members of this chemical group is variable. METHODS: A retrospective analysis of clinical patch test data obtained with a special test series in the centres of the Information Network of Departments of Dermatology (IVDK) between 1995 and 1999. RESULTS: In the 638 patients tested with the above test panel positive reactions were observed most often to p-aminoazobenzene (16.2%), p-phenylenediamine (14.1%), p-toluylenediamine (10.0%), followed by 4,4'-diaminodiphenylmethane (8.5%), Disperse Orange 3 (8.4%) and p-aminophenol (3.1%). Among the 544 patients tested with p-phenylenediamine and all seven additional 'para amino' compounds, concordance between reactions varied greatly. The stronger the positive test reaction to p-phenylenediamine, p-toluylenediamine or p-aminoazobenzene, the more frequently additional positive reactions to the other compounds were observed. CONCLUSIONS: A screening employing several 'para amino' compounds is necessary to describe the individual spectrum of allergic contact sensitization, as there is no reliable marker substance. Further research should aim at (i) establishing the mechanism of cross-reactivity to 'para amino' compounds and (ii) identifying exposures in the environment.
The main allergenic constituents of Compositae plants are the sesquiterpene lactones (SLs). In recent years, a mixture of three SLs, each with a different sesquiterpene skeleton (alantolactone, dehydrocostuslactone or costunolide), has been routinely used to detect Compositae allergy. The purpose of our study was to establish the value of testing with a range of Compositae extracts. Ninety-seven consecutive patients with exposure pattern dermatitis or hand eczema and gardening as a hobby or occupation were patch tested to the European standard series including SL mix 0.1% pet., Compositae extracts and other relevant allergens. Twenty-six of the 97 patients tested showed allergic reactions to SL mix or Compositae extracts. Fifteen of these showed positive reactions to both the SL mix and Compositae extracts. Eleven patients showed a negative reaction to the SL mix but positive reaction to the Compositae extracts. Dandelion elicited a positive reaction in eight of the 11 SL mix-negative patients and three patients reacted to feverfew. The SL mix failed to detect 38% of our Compositae-sensitive patients. Dandelion extract alone detected 73% of SL-negative patients. Additional testing with feverfew extract would have detected 91% of the SL mix-negative individuals. Our study highlights the importance of testing the response of SL-negative patients to additional Compositae extracts when there is a clinical suspicion of Compositae allergy.
Data on allergic contact dermatitis from acrylates and 4 patients sensitized during routine patch testing are reported. During 1982-1985, we used 7 different acrylates for tests. 1 patient out of 22 (= 4.5%) was sensitized to ethyl acrylate and butyl acrylate (1% pet.). Since September 1985, we have used a commercial (meth)acrylate series containing 28 substances. 3 of 24 patients tested became sensitized to ethyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate (0.5% pet.). Because active sensitization with acrylates can be very harmful, it may be necessary to use lower concentrations than recommended. Currently, we test ethyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate at 0.167% pet.