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At least 127 records · Page 7Linked to original sources

Studies of atopic patch tests.

35 patients were patch-tested for 72 h with house dust mite, timothy- and birch-pollen, Cladosporium herbarum and hen's egg white allergens, prepared in a cream in concentrations up to 1,000 times the concentration used for skin prick testing. 6 patients developed a total of 10 positive reactions. All the strong positive patch-test reactions occurred in patients with a strong positive skin prick test to the same allergen. Immunohistochemical studies of biopsied positive patch-test reactions demonstrated a mononuclear cell-infiltrate in the upper part of dermis, consisting mainly of T-cells, with a slight predominance of T-helper-cells as compared to T-suppressor cells, and about 10% CD1 positive cells. No significant responses were obtained in peripheral blood mononuclear cell-cultures stimulated with the various allergens. A positive patch-test reaction to birch-pollen was successfully transferred passively to a non-allergic-recipient, suggesting that the positive reaction may depend upon sensitizing factor(s) in the serum.

Adolescent↗

Audit of primary and secondary care as a source of patch test clinic referrals.

BACKGROUND: Referral for patch testing is important in managing patients with eczema/dermatitis. These referrals come from many different sources. OBJECTIVES: To assess the appropriateness of referrals from general practitioners (GPs) to a dedicated patch test clinic. METHODS: Referral sources were recorded for patch testing in a dedicated contact dermatitis unit for a 4-month period between November 2002 and February 2003. RESULTS: Of 217 referrals reviewed, 45 (21%) were received from GPs. There was no significant difference in the percentages of positive patch test results and of relevant positive patch test results obtained from GP referrals compared with those received from other sources, including dermatology departmental referrals. CONCLUSIONS: Referrals from GPs, if selected appropriately, can be seen directly in the patch test clinic without prior assessment in a general dermatology clinic.

Clinical Competence↗

Increases in human epidermal DR+CD1+, DR+CD1-CD36+, and DR-CD3+ cells in allergic versus irritant patch test responses.

In an attempt to differentiate an allergic patch test response from an irritant response, we evaluated by flow cytometry the percentages of various epidermal cell populations isolated from allergen and irritant-treated patch test sites. Nine allergic individuals were patch tested with various allergens (Rhus, dinitrochlorobenzene [DNCB], or nickel chloride) and a vehicle control for 48 h. Eight additional individuals were patch tested with irritating chemicals (sodium lauryl sulfate or nonanoic acid) and with a vehicle control for 48 h. Epidermal cells, isolated from suction blisters, were double labeled for CD1/HLA-DR, CD3/HLA-DR, or CD36/HLA-DR cell surface markers and analyzed by flow cytometry to determine the percentage of various cell populations. A mean increase of 0.91 +/- 0.3 in the percentage of DR+CD1+ Langerhans cells over the vehicle control patch test site was detected in allergen-positive patch test sites in allergic individuals, whereas a decrease of 0.19 +/- 0.2 in the percentage of DR+CD1+ Langerhans cells from the vehicle control patch test site was detected in irritant-treated patch test sites. Epidermal cells from allergen-positive patch test sites also exhibited an increase of 5.2 +/- 1.8 in percentage of DR+CD1- cells over the vehicle control patch test site compared to an increase change of 0.8 +/- 0.4 in epidermal cells isolated from irritant-treated patch test sites. We also found that DR+ cells that lacked the CD1 determinant expressed the macrophage/monocyte antigen CD36 (OKM5). Finally, a 2.3 +/- 0.8 increase in the percentage of DR-CD3+ cells over the vehicle control patch test site was observed in allergen-positive patch test sites compared to an increase of 0.2 +/- 0.2 observed in irritant-treated patch test sites. These results demonstrate a significant increase in DR+CD1+, DR+CD1-CD36+, and DR-CD3+ epidermal cells in allergen-positive patch test sites compared to irritant patch test sites.

Adult↗

Skin localization of cow's milk proteins delivered by a new ready-to-use atopy patch test.

PURPOSE: Atopy patch tests (APTs) allow the detection of delayed allergies at the skin level. The localization of beta-lactoglobulin delivered into the skin by an innovative ready-to-use APT (E-patch was investigated and the efficacy and safety of this device were assessed. METHODS: The E-patch containing beta-lactoglobulin was placed for 24 h in contact with hairless rat skin mounted in a Franz diffusion cell. Transdermal passage was monitored by measurement of beta-lactoglobulin A-[methyl-(14)C] or by two-site enzyme immunoassay. An iterative skin stripping allowed measurement of the beta-lactoglobulin penetrating the first external skin layers. RESULTS: After 24 h, 92% of beta-lactoglobulin remained on the skin. The iterative skin strippings showed a 135-fold higher concentration of beta-lactoglobulin in the stratum corneum than that found in the epidermis-dermis. Analysis of the solution in the receiver compartment by radioactivity assays or immunoassays indicates that intact protein did not cross the skin. CONCLUSIONS: The E-patch system allows native beta-lactoglobulin to concentrate in the stratum corneum, in the vicinity of immunological cells, but does not lead to its systemic delivery. Therefore, it is suggested that this delivery system creates ideal conditions for promoting a positive topical response with reduced risk of systemic anaphylactic reactions caused by the native form of the beta-lactoglobulin A.

Animals↗

Rate of patch test reactions to a Dermatophagoides mix currently on the market: a mite too sensitive?

BACKGROUND: There long has been debate over the role of the dust mite antigen Dermatophagoides in provoking or perpetuating atopic and other forms of dermatitis, particularly airborne contact dermatitis. Reactivity to Dermatophagoides has been measured by specific IgE and by immediate-type responses to prick test challenge. More recently, patch testing has been advocated as a means of determining reactivity to Dermatophagoides. OBJECTIVE: To determine patch test reactivity to a Dermatophagoides mix in a population receiving patch testing. METHODS: A commercially available mix of 2 species of Dermatophagoides, Dermatophagoides pteronyssinus and Dermatophagoides farinae, recently became available. The authors chose the lower available concentration of this mix (20%) and added it to their standard patch testing tray between December 1999 and January 2001. Results were interpreted in the standard manner. RESULTS: A total of 662 patients received patch testing to Dermatophagoides (men 32%, women, 68%). Mean age was 53.4 years (range, 37 to 94). The Dermatophagoides mix was the most common allergen in the standard tray to evoke a reaction. At 96 hours, positive reactions were noted in 55% of patients. The reactions were interpreted as irritant in 16.2%, relevant in 6.7%, of questionable relevancy in 30.5%, and of no relevancy in 32.6%. The majority of reactions were of the "crescendo" pattern. CONCLUSION: The currently available formulation of Dermatophagoides mix, even at its lower concentration, led to a high rate of reactivity with a low rate of relevance.

Adolescent↗

Analysis of para-phenylenediamine allergic patients in relation to strength of patch test reaction.

BACKGROUND: Despite having a positive patch test reaction to para-phenylenediamine (PPD), some patients continue to dye their hair, while others are forced to give up or abandon this practice. This difference in patient behaviour could be due to the degree of sensitization. OBJECTIVES: To establish whether the ability to continue dyeing hair in PPD allergic patients is related to the strength of patch test reaction. To note differences in other clinical features in relation to the strength of patch test reaction. METHODS: We analysed retrospectively the patch test records of 400 sequential PPD-positive patients for the strength of patch test reaction (+, ++, +++) and different clinical features. Data were analysed using Cochran-Mantel-Haenszel chi2 tests. RESULTS: There was a strong linear relationship between the strength of patch test reaction and continuation with hair dyeing. Patients were more likely to report a history of hair dye reaction with increasing strength of patch test reaction. There was no difference in strength of patch test reaction in relation to age, site of rash, occupation (hairdressing) or history of atopic eczema. Overall concomitant reactivity with related aromatic amine allergens (benzocaine, N-isopropyl-N-phenyl-para-phenylenediamine, para-aminobenzoic acid) was infrequent. CONCLUSIONS: Patients with stronger patch test reactions (++, +++) are more likely to have a clear history of reacting to hair dye and are less likely to still be dyeing their hair.

Adolescent↗

Seasonal influence on patch test results in Greece.

Several studies have been reported on the suppressive effect of ultraviolet B (UVB), UVA sunlight and PUVA on contact dermatitis. However, studies that have tested the hypothesis that patch tests reactions have a seasonal variation due to the suppressive influence of sunlight, had found conflicting results. In order to clarify the influence of climate conditions in Athens, Greece (sunlight, temperature, latitude 38 degrees) on patch tests results, data from 5468 patch-tested patients (1978-1990) were analyzed for monthly, seasonal variation. In addition, 180 patients with a high degree of sun exposure due to occupation that were prospectively re-patch-tested in a different season (i.e. summer versus winter), with the same allergens and technique, were studied and analyzed statistically. Climate data was provided by the Hellenic National Meteorological Service. The results indicate that there is no significant influence on patch tests reactions in Athens, Greece. This may in part be due to the small differences in climate conditions that exist between summer and winter in Greece.

Allergens↗

Electron microscopy of epidermal and dermal Langerhans' cells in long-lasting allergy patch tests.

In rare cases, normal allergy patch tests persist for weeks or months. Here, seven biopsies from six patients with long-lasting allergy patch tests, taken 15-75 days after allergen challenge, were analysed by transmission electron microscopy. In accordance with clinical expression of the test site, fine structural evidence of persistent activity of immunocompetent cells in the epidermis and dermis was observed. Moderate numbers of exocytic lymphocytes and macrophages were seen in the epidermis. Langerhans' cells (LC) appeared active, and LCs with Birbeck granules were detected both in the epidermis and the dermis and were also seen to cross the dermoepidermal junction. LC-mononuclear cell contacts were more frequent in the epidermis than is normal in allergy patch tests. A strong infiltrate of lymphocytes, macrophages, fibroblasts, mast cells, and cells resembling LCs but devoid of Birbeck granules, i.e. indeterminate cells, was seen in the upper dermis. Less than 10% of the dermal cells showing the fine structural appearance of LCs had Birbeck granules, as seen in a single section. Both indeterminate cells and LCs were apposed by lymphocytes in the dermis, often in a rosette-like fashion. The present paper is descriptive but gives background to the understanding of events in long-lasting allergy patch tests. However, the reason for and the basic mechanisms of long-lasting allergy patch tests are not known. A defect in down-regulation of the contact hypersensitivity reaction and/or a constant antigen stimulation could be responsible for the persistence of these allergy patch test reactions.

Epidermis↗

Single doses of local betamethasone do not suppress allergic patch test reactions to nickel sulfate.

Topical corticosteroids are usually banned on test areas prior to patch testing. The previous literature on the effect of topical corticosteroids is conflicting. Patients allergic to nickel sulfate were patch tested on 4 sites with nickel on day (D) 0. Intracutaneous betamethasone was injected to test sites on D-1, D0 and D1. NaCl injection on D-1 was control. The patch test reactions were evaluated clinically and with laser Doppler. There were no differences in patch test reaction intensities on sites treated with intracutaneous betamethasone as compared to control. A single local dose of potent corticosteroid does not suppress allergic patch reactions to nickel. The current practice of avoiding topical corticosteroid use prior to patch testing should be re-evaluated.

Allergens↗

Dose-response testing with nickel sulphate using the TRUE test in nickel-sensitive individuals. Multiple nickel sulphate patch-test reactions do not cause an 'angry back'.

The aim of this study was to employ the TRUE test assay to confirm the presence or absence of the 'angry back' phenomenon, i.e. that a strong positive patch-test reaction heightens adjacent patch-test response. In addition, we wished to establish the dose-response relationship for nickel sulphate patch tests among nickel-sensitive patients. Seventy-two nickel-sensitive patients, 36 in Odense and 36 in Stockholm, were tested with a 10-step nickel sulphate dilution series (TRUE test) and two placebo patches. The position of the patches was rotated, to provide a balanced spatial distribution of the different concentrations. Readings were performed blind. The results were analysed by means of polynomial multiple-regression methods and a logistic dose-response model. Half the patients (38/72) had a threshold patch-test concentration for nickel sulphate in the range of 3-0.3 microgram/cm2. The 'angry back' phenomenon was not apparent in this study, as the spill-over effect was not statistically significant. Strong reactions to high concentrations of nickel sulphate did not enhance the response to adjacent lower concentrations of nickel sulphate.

Dermatitis, Allergic Contact↗

Macro-video documentation patch tests.

An unequivocal distinction between allergic and irritant patch test reactions is often difficult with patch tests. This study was designed to evaluate the worth of video-macro camera documentation for differentiation between allergic and irritant test reactions and to investigate whether there are characteristic clinical differences in patch test responses between metal salts and fragrances. Patch testing was performed with nickel sulfate, fragrance mix and an irritant, sodium lauryl sulfate 1% aq., on the upper back of 82 patients, with evaluation and computer-aided video documentation after 48 and 72 hr. No reliable clinicomorphological criterion was found for assessing a weak patch test reaction as being definitely allergic. Even characteristic papules and vesicles were not regularly found in allergic reactions. However, unlike fragrance mix, patch test reactions to nickel sulfate were characteristic in that they showed a heterogeneous spread and an association with hair follicle openings, independent of reaction intensity. Evaluation based on additional computer-aided video-macro camera documentation did not add further advantage for the differentiation of allergic and irritant reactions. But well-defined clinicomorphological features and reaction patterns to single test substances or even whole substance categories could be helpful additional criteria for evaluating patch test responses in clinical practice.

Adult↗

Technical and ethical problems associated with patch testing.

When relevant allergens are identified by patch testing, and patients can avoid them in their environment, improvement of dermatitis is the rule. Some forms of chronic dermatitis may not clear completely, but patients are usually satisfied with modification of their previously more severe problem. In 1981 when asked what he felt were the five most important advances in clinical dermatology during the 20th century, Dr. Marion B. Sulzburger, an icon in American dermatology, said that, "The increased use and usefulness of the patch test and the international standardization of test concentrations and methods" was number one. Those of us who are enthusiastic patch testers and fascinated by the evaluation of patients with irritant and allergic contact dermatitis would agree. It is a thrilling clinical experience to be able to tell a machinist that he need not stop his lifelong occupation, but instead will do fine if he will simply avoid the waterless hand cleanser he has been using which is preserved with glutaraldehyde. The woman whose facial dermatitis has embarrassed her for years and clears when she stops using the Quaternium-15 preserved moisturizer that you have identified in your patch testing is grateful to you forever, and again happy in her own life. In 1991, my research assistants, Patricia Norris and Mary Lou Belozer, and I studied 30 university hospital workers who answered our advertisement asking for individuals who believed they were troubled by their rubber gloves (unreported study). By evaluating these people through history, physical examination, and patch testing, we were able to prove glove relatedness in 14 of them. Nine of the 14 had contact urticaria to latex, and only 5 had allergic contact dermatitis to rubber glove ingredients. Fifteen of our patients had irritant dermatitis. In this study, none of the patients with allergic contact dermatitis to glove ingredients had contact urticaria. However, since that time, we have observed a number of patients who had both forms of allergic reaction. Three of our patients who presented with nummular (patchy) hand dermatitis also had contact urticaria to latex, but no positive patch tests. With latex glove avoidance, their dermatitis resolved; an example of how scratching urticaria can eventuate in longer lasting dermatitis in some people ("the itch that rashes"). The patients presented to their dermatologist with dermatitis, but their true initiating event was urticaria which lasted only hours. The gratifying part of this study was that patch testing and contact urticaria testing allowed us to discover the 5 patients with allergic contact dermatitis and the 9 patients with contact urticaria who could benefit from glove alternatives. We were also able to assure patients in the remainder of the group that their hand eczema was not glove induced, but rather was related to their wet work. In most instances, therapeutic intervention helped, but in several cases job changes were required. Patch testing, when done properly, produces exciting results. When done improperly, it confuses and misleads patients and results in embarrassment to physicians who cannot properly interpret their results. Should a physician choose to include patch testing in his or her evaluation of patients with contact dermatitis it is essential, in my view, that he or she have highly developed skills in the diagnosis and treatment of skin diseases, and that these physicians be elaborately trained in the techniques of application and the methods of interpretation of patch tests.

Ethics, Medical↗

Diagnostic accuracy of the atopy patch test and the skin-prick test for the diagnosis of food allergy in young children with atopic eczema/dermatitis syndrome.

AIM: To evaluate the diagnostic value of the skin-prick test and the atopy patch test in diagnosing basic food allergy in young children suffering from atopic eczema/dermatitis syndrome. METHODS: 141 children, the majority under 2 y of age (mean 16 mo) with atopic eczema/dermatitis syndrome were investigated using skin-prick and atopy patch tests for milk, egg, wheat and rye. Open diagnostic elimination challenge was done since this has been reported to be a reliable method in young children. RESULTS: A positive challenge response was found to milk in 63 (45%), egg in 78 (55%), wheat in 61 (43%) and rye in 61 (43%). Sensitivity/specificity of the atopy patch test was 60%/97% for milk, 71%/97% for egg, 90%/94% for wheat and 93%/90% for rye. For the skin-prick test the corresponding figures were 41%/99%, 60%/97%, 13%/98% and 15%/99%. CONCLUSION: Patch testing was found to be a more sensitive method than the skin-prick test in diagnosing food allergy in children with atopic eczema/dermatitis syndrome, especially in those under 2 y of age. Many children with a negative skin-prick test result have a positive patch test result, especially in the case of cereals. A diagnosis of food allergy should be confirmed by elimination and in the research setting also by challenge.

Child, Preschool↗

Should macular erythema reactions be counted as positive allergic patch-test reactions?

BACKGROUND: Positive allergic patch-test results are generally described as erythematous papules, vesicles, or a spreading reaction with crust and ulceration. This description excludes milder reactions, including macular erythema. OBJECTIVE: Our aim was to investigate the prevalence and relevance of reactions graded as macular erythema at Mayo Clinic. METHODS: Between January 2001 and June 2004, patients suspected of having allergic contact dermatitis were patch-tested with our institution's standard patch test, a screening series of 68 to 72 allergens. In total, 2,823 patients were patch-tested with 193,530 allergen applications. Reactions were interpreted with the North American Contact Dermatitis Group scale, including and excluding reactions graded as macular erythema. Irritant reactions were excluded from calculations. For this study, scores for current, questionable, and past relevance were combined. RESULTS: On day 5, with the exclusion of reactions graded as irritant, 7,274 allergen applications were associated with reactions, including 3,082 (42.4%) that were graded as macular erythema. Of the macular erythema reactions, 2,430 (78.8%) were graded as relevant. The rate of reaction in our patients was 2.2% if macular erythema was excluded, 3.8% if all macular erythema reactions were included, and 3.4% if only those macular reactions deemed relevant were included. CONCLUSION: Patch-test reactions rated as macular erythema are common and may be of clinical relevance. For the purposes of patient education, they should not be disregarded. Consideration should be given to including these reactions when reporting patchtest results.

Allergens↗

Diagnostic patch test concentration for Kathon CG.

Patch test studies, 21-day cumulative irritancy assays and Draize repeat insult patch tests with Kathon CG, were used to ascertain an appropriate diagnostic patch test concentration. A dilution of 100 ppm a.i. (aq. or pet.) appears to have low irritancy potential. Further observations are required to verify if this concentration is high enough to detect most cases of sensitization.

Adolescent↗

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.

Allergens↗

Reproducibility of patch test results: a concurrent right-versus-left study using TRUE Test.

Wide variations in the reproducibility rate of positive patch test responses have been reported. We hypothesized that a major source of non-reproducibility resides in the methodological pitfalls of routine patch testing. Simultaneous duplicate patch testing on opposite sides of the upper back was performed on 500 consecutive patients, using the TRUE Test system consisting of 2 panels, each one containing 12 standard allergens. A rigorous methodological design was applied and relevance was assessed for all discordant patch test reactions. A total of 435 positive patch test reactions were observed either on one or both sides in 289 patients (58.8%). Of these, 22 (5%) were discordant, i.e. interpreted as positive allergic on one side whilst negative or doubtful on the opposite side. The allergens responsible for discordant reactions were nickel sulfate (4 patients), cobalt chloride (3), lanolin alcohol (3), fragrance mix (2), carba mix (2), thiuram mix (2), colophonium (1), potassium dichromate (1), p-phenylenediamine (1), formaldehyde (1), balsam of Peru (Myroxylon pereirae resin) (1) and thimerosal (1). Of the 19 (4%) patients with discordant patch test reactions, the allergen was deemed to be of definite present or past relevance in 9 patients (1.8% of the total and 3.1% of all patients with positive patch test reactions) and of possible relevance in a further 2 patients. These data suggest that patch testing is a reasonably reproducible procedure as long as methodological error is minimized.

Adolescent↗