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Biomedical subjects

S Seidenari

Publications and source records attributed to S Seidenari.

At least 19 recordsLinked to original sources
PubMed1997

Cross-sensitizations between azo dyes and para-amino compound. A study of 236 azo-dye-sensitive subjects.

Combined sensitizations to different azo dyes, probably based both on true cross-sensitization and on simultaneous positive reactions, have frequently been described. However, since azo dyes are included in the standard series in a minority of countries, the case studies considered comprise, with few exceptions, a small number of subjects. The aim of our study was to investigate cross-reactions between different azo dyes and para-amino compounds in azo-dye-sensitive subjects, to study the clinical aspects of azo dye dermatitis, to assess the relevance of sensitization to azo dyes, and to relate the pattern of cross-sensitizations to the chemical structure of the different dyes. Out of 6203 consecutively tested patients, 236 were sensitized to at least 1 of 6 azo compounds employed as textile dyes, included in our standard series. 107 subjects reacted to Disperse Orange 3 (DO3), 104 to Disperse Blue 124 (DB124), 76 to p-aminoazobenzene (PAB), 67 to Disperse Red 1 (DR1), 42 to Disperse Yellow 3 (DY3), and 31 to p-dimethylaminoazobenzene (PDAAB). Co-sensitizations to para-phenylenediamine were present in most subjects sensitized to DO3 (66%) and PAAB (75%), in 27% and 36% of DR1 and DY3-sensitive subjects, and only in 16% of subjects sensitized to DB124. Apart from the hands and the face, the neck and the axillae were the most frequently involved skin sites. Whereas the involvement of flexural areas was mainly connected with sensitization to DB124, in patients with hand dermatitis and in those working as hairdressers, sensitization to DO3 and PAAB was more frequent. Moreover, in the former patient group, a history of textile dye allergy was most frequently obtained. Out of 33 patients tested with an additional textile dye series, only 5 subjects reacted to anthraquinone dyes. Cross-sensitizations between azo dyes and para-amino compounds can partially be explained on the basis of structural affinities.

Azo Compounds↗
PubMed1996

Skin reactivity to sodium lauryl sulfate in patients with respiratory atopy.

BACKGROUND: No literature data are available on the skin reactivity of patients with respiratory atopy alone. OBJECTIVE: Our purpose was to assess skin reactivity to detergents in patients with allergic asthma, rhinitis, or both. METHODS: The skin of the volar aspect of the forearm of 19 subjects with allergic asthma or rhinitis (or both) was challenged with a single exposure to 0.5% sodium lauryl sulfate. The skin response was evaluated by transepidermal water loss (TEWL), capacitance, and echogenicity measurements. Results were compared with those obtained in 19 patients with atopic dermatitis (AD) and 20 healthy subjects. RESULTS: In patients with AD preexposure TEWL values were higher than in healthy subjects, whereas capacitance values were lower. In this patient group, postexposure TEWL, capacitance, and echogenicity values showed more pronounced variations than in healthy subjects. Conversely, in patients with allergic asthma or rhinitis (or both), both baseline and postexposure TEWL, capacitance, and echogenicity values were similar to those in healthy subjects. CONCLUSION: Patients with respiratory atopy without AD do not have the functional abnormalities characteristic of skin affected by AD, either under baseline conditions or after exposure to sodium lauryl sulfate.

Adult↗
PubMed1996

Pre-treatment of nickel test areas with sodium lauryl sulfate detects nickel sensitivity in subjects reacting negatively to routinely performed patch tests.

A fair % of patients with a clinical history of nickel allergy show negative patch test results. To improve the response rate to NiSO4 5% pet. patch tests, a testing procedure utilizing pre-treatment of the test area by a 24-h application of sodium lauryl sulfate (SLS) was introduced. 46 women with a clinical history of nickel sensitivity, who exhibited negative reactions to nickel sulfate 5% pet. patch tests, were studied. Patients underwent 6 patch tests on adjacent sites on the volar surface of the forearms. 4 patch tests were performed with a 72-h application of 40 mg nickel sulfate 5% pet. While 1 of these patch tests served as control, 3 test areas underwent 24-h pre-treatment with 40 microliters SLS, 1 with 0.1% and 2 with 0.5% solution. To evaluate differences in the reactivity to SLS plus nickel sulfate related to the site on the forearm, 0.5% SLS pre-treatment was performed both on a proximal and on a distal test site. At the 72-h evaluation, 19 subjects out of 46 showed positive reactions to nickel sulfate 5% pet. at skin sites pre-treated with 0.1% SLS, whereas 23 patients reacted positively at 0.5% SLS pre-treated areas. Echographic values of skin thickness and of hypo-echogenic dermal areas at positive pre-treated nickel test areas were higher than at control test areas, confirming the clinical evidence of an increased response to NiSO4 after SLS pre-treatment. The inflammatory reaction, as evaluated clinically and echographically, was much higher at distal skin areas (0.1% SLS and distal 0.5% SLS) than at proximal 0.5% SLS ones.

Adult↗
PubMed1996

Sensitization to reactive textile dyes in patients with contact dermatitis.

Reactive dyes are used especially for colouring natural fibres (cotton, silk and wool) that are widely used in Western countries, particularly Italy, in the production of clothes. The aim of our study was to investigate sensitization to the most commonly used reactive textile dyes in patients undergoing patch tests, and to assess the clinical relevance of contact sensitization to these dyes. 1813 consecutive patients underwent patch tests with the GIRDCA standard series and an additional textile series of 12 reactive dyes. 18 of these patients were sensitized to reactive dyes (0.99%) (4 only to reactive dyes). The dyes most frequently responsible for positive patch tests were Red Cibacron CR and Violet Remazol 5R (respectively, 8 and 5 positivities). In 5 cases only was a history of intolerance to particular garments given; of 4 patch tests performed with pieces of garment, 2 were positive. In 1 occupationally-exposed patient, airborne contact dermatitis was suspected. Owing to the lack of up-to-date patch test series, some cases of allergic contact dermatitis from textile dyes are probably misdiagnosed: new colouring agents are continuously introduced to the market, so that a close relationship with textile industry is necessary to improve our diagnostic tools.

Adolescent↗
PubMed1996

Ultrasound description and quantification of irritant reactions induced by dithranol at different concentrations. A comparison with visual assessment and colorimetric measurements.

Dithranol (D) is used as a therapeutic topical agent to treat psoriasis, although it produces inflammation and staining of skin and clothing. D-induced irritation has been evaluated by visual scoring and by bioengineering techniques, evidencing modifications of the inflammatory parameters, but no alterations of the skin barrier. The aim of our study was to evaluate the irritant reactions induced by D using ultrasound, and to compare the B-scanning data with visual assessments and colorimetric measurements. 13 healthy women underwent 2, 3-h patch tests with, respectively, 0.02% and 0.1% D in white petrolatum and 1 24-h patch test with 2% sodium lauryl sulfate (SLS). For assessing skin reactions, clinical judgement, colorimetry and echography were employed. Echographic images were evaluated by skin thickness measurements and segmentation procedures, using an 0-30 interval, marking the hyporeflecting areas in the dermis, and a 201-255 interval, assessing the hyperreflecting components of the image (both epidermal and dermal). In all subjects, D produced uniform reactions, the intensity varying according to concentration. Both echographic parameters of inflammation (skin thickness and 0-30 areas) showed an increase at all times of assessment. The 201-255D/0-30 pixel ratio, describing the distribution of dermal edema, indicated that strong inflammatory reactions, such as those caused by the application of 0.1% D, are accompanied by edema in the lower portion of the dermis. Finally, in contrast to SLS reactions, where a 24-h reduction in epidermal reflectivity was observable, D reactions appeared with an accentuation of the 201-255 epidermal band at 24-96-h examinations.

Administration, Topical↗
PubMed1996

Statistical evaluation of the persistence of acquired hypersensitivity by standardized patch tests.

Numerous studies have focused attention on the influence of various biological and environmental factors on contact hypersensitivity. In order to evaluate the persistence and/or modification of allergic contact sensitivity to a number of common contact sensitizers, the same standardized patch tests were repeated on 174 subjects with contact sensitivity after a time lapse of 5 years (1987-1992). In 18.4% of the cases, 1 or more sensitivities were lost; 28.7% of the patients had a higher number of positive patch tests after 5 years, while the remaining 52.9% of the patients showed no change in the number of positive patch tests. In 88%, the positive allergens were unchanged, whereas in the remaining 12% of the subjects, they showed 1 or more variations. The association between the allergens most often positive was calculated for both the 1st and the 2nd patch test results. Moreover, to evaluate the frequency of an allergen's positivity, we studied the disappearance of old sensitivities and the appearance of new sensitivities by the McNemar test. Cobalt chloride was the only allergen with a significant frequency of new positivities over the period of observation (p < 0.01). Logistic regression analysis was performed to evaluate the possible influence of positive tests to other allergens, and of some clinical findings associated with contact dermatitis, on the sensitivity to cobalt chloride in 1987 and in 1992.

Adult↗
PubMed1996

No alteration of biophysical parameters in the skin of subjects with respiratory atopy.

BACKGROUND: Skin hyperreactivity to environmental factors in patients with atopic dermatitis has been extensively studied. Conversely, little is known on the biophysical parameters of the skin in patients with respiratory allergy. OBJECTIVE AND METHODS: Functional characteristics of the skin in subjects with allergic asthma and/or rhinitis were studied using evaporimetry, capacitance and pHmetry. Data were compared to those of healthy subjects and patients with atopic dermatitis (AD). RESULTS AND CONCLUSIONS: Our results suggest that the skin of patients with atopic respiratory allergy does not show altered biophysical parameters when compared to normal skin, confirming that the functional alterations in AD skin are linked to the expression of the atopic diathesis in the skin.

Adolescent↗
PubMed1996

A quantitative description of echographic images of sclerotic skin in patients with systemic sclerosis, as assessed by computerized image analysis on 20 MHz B-scan recordings.

The aim of our study was to find image descriptors enabling the characterization of sclerotic skin and its differentiation from normal skin, in order to find an objective method for the assessment of skin involvement in systemic sclerosis (SSc). Echographic evaluations were carried out using a 20 MHz B-scanner, on 18 female patients with SSc and on 20 healthy women serving as controls, at 3 different skin sites (forehead, cheek and back of the hand). Images were processed by a program, based on segmentation procedures and object description, employing 5 different amplitude bands and the following parameters: 1) the extension of image areas marked by amplitude bands of interest, 2) the percentage of the image surface reflecting within a homogeneous amplitude band, 3) the number of objects composing the image, 4) the average object size, and 5) the "density" of the objects. At all 3 skin sites, marked differences in the echostructure of the tissue between patients with SSc and the controls were observable. In SSc patients forehead skin appeared thinner and more echogenic, with smaller hypo-reflecting objects and greater hyper-reflecting areas; cheek skin showed an increase in intermediate-high amplitude components, with greater and more numerous hyper-reflecting objects, and smaller and less numerous hypo-reflecting ones; the skin on the back of the hand was thicker, less echogenic, with large hypo-reflecting areas and small hyper-reflecting objects. By image processing these parameters were numerically described. Values referring to sclerotic skin significantly differed from those of normal skin. This echographic procedure is proposed as a method representing a first step towards the quantification of the spontaneous course of SSc and of response to therapy.

Adult↗
PubMed1995

Contact allergy to Dermatophagoides in atopic dermatitis patients and healthy subjects.

To compare different house-dust-mite-derived allergenic materials and to correlate the presence of IgE to Dermatophagoides with patch test results, 313 atopic dermatitis (AD) patients and 100 healthy volunteers (HV) underwent patch tests with: Dermatophagoides pteronyssinus (DPT) lyophilized purified alpha fraction in buffered saline/glycerol 50% and/or in petrolatum (Bayropharm); 50% DPT and 50% Dermatophagoides farinae (DF) whole bodies in petrolatum and petrolatum oil (Allergopharma-Bracco); DPT and DF whole bodies in petrolatum and petrolatum oil (Lofarma). We found 39% positive reactions among AD subjects and 13% in HV. The presence of serum-specific IgE did not influence the patch test results. 38% of AD patch-test-positive patients and 4 of 13 HV, respectively, showed a positive prick test and/or RAST to Dermatophagoides. Similar sensitization rates were observed with the allergenic material from Bayropharm (54% positives) and Allergopharma-Bracco (51% positives), whereas the preparations from Lofarma gave a 20% response rate.

Adolescent↗
PubMed1995

Prevalence of contact allergy to non-disperse azo dyes for natural fibers: a study in 1814 consecutive patients.

5 non-disperse azo dyes, used for colouring natural fibers, were added to the standard patch test series, as 5% pet. preparations. 1814 consecutive patients attending the patch test clinic were patch tested, of whom 16 (0.88%) reacted to the newly added dyes: 8 to Direct Orange 34, 5 to Acid Yellow 61, 2 to Acid Red 359 and 1 to Acid Red 118. On the basis of clinical history and results of patch tests with pieces of fabrics, contact sensitization to non-disperse azo dyes seemed to be related to the appearance of skin lesions at least in 8 subjects. We conclude that systematic exploration of the sensitizing potential of textile dyes, selected after careful investigation, can provide additional information on the frequency of occurrence of textile dye dermatitis, supporting individual investigation in sensitized subjects.

Adolescent↗
PubMed1995

Pretreatment of the test area with 1-day occlusion improves the response rate to NiSO4 5% pet. patch tests in subjects with a positive history of nickel allergy.

A group of 58 women, aged 18 to 51 years, with a clinical history of nickel allergy, who exhibited equivocal or negative reactions to nickel sulfate 5% pet. patch tests performed on the skin of the back, were recruited consecutively from the patch test clinic from September 1993 to June 1994. In order to improve the response rate to NiSO4 5% pet. patch tests, a testing procedure utilizing pretreatment of the test area by 1-day (24-h) occlusion was introduced. Patients underwent 2 patch tests on adjacent sites of the volar surface of both forearms. 3 of the patch tests were performed with 40 mg nickel sulfate 5% pet., whereas a control test was carried out by occluding with an empty chamber. 2 of the nickel sulfate test sites were pretreated with 1-day occlusion performed with an empty chamber. A visual grading system and echographic measurement were used to quantify the responses 30-40 min after patch test removal. Echographic evaluations were carried out using a 20 MHz B-scanner. Measurement of skin thickness and determination of the hypoechogenic dermal area, both considered to be parameters of inflammation, were used to evaluate the intensity of the allergic reaction. At the 3-day (72-h) evaluation, 19 subjects out of 58 clearly showed positive reactions to nickel sulfate 5% pet. at pre-occluded skin sites. Moreover, values of skin thickness and of 0-30 areas at positive pre-occluded nickel test areas were higher in respect to control test areas, confirming clinical evidence of increased response to NiSO4 after occlusion.

Adolescent↗
PubMed1995

Objective assessment of the skin of children affected by atopic dermatitis: a study of pH, capacitance and TEWL in eczematous and clinically uninvolved skin.

In order to obtain objective data on skin functions in subjects with atopic dermatitis (AD), according to the different phases of the disease, we evaluated the skin of children with AD instrumentally and compared it to that of healthy subjects of the same age group. One hundred patients, aged 3 to 12, and 21 healthy children were studied by means of measurements of pH, capacitance and transepidermal water loss (TEWL) at 8 different skin sites. At the moment of the investigation 55 children out of 100 presented skin lesions on at least one of the assessed skin areas, whereas 45 had been free from eczema for at least 1 month. Considering all skin sites together, significant differences were found between mean values of pH, capacitance and TEWL of eczematous skin, both in respect to those referring to apparently healthy skin in the same patients and in respect to the skin of control subjects. Moreover, TEWL, pH and capacitance values referring to uninvolved skin of AD patients significantly differed from those of healthy subjects. Finally, when values referring to patients with skin lesions and to patients without lesions were separately considered, significant differences concerning the parameters of uninvolved skin were observed. These data show that, in subjects with AD, skin functions undergo fluctuations according to the phase of the disease and support the hypothesis that the presence of active eczema determines an impairment of the barrier of uninvolved skin, even at sites far from active lesions.

Child↗
PubMed1995

Quantitative description of echographic images of morphea plaques as assessed by computerized image analysis on 20 MHz B-scan recordings.

In order to find image descriptors enabling the characterization of sclerotic skin of morphea plaques and their objective differentiation from normal skin, we studied 52 lesions in 35 patients affected by plaque type morphea. Echographic evaluations were carried out using a 20 MHz B-scanner, providing cross-sectional images of the skin. Images were processed by a program providing a numerical representation of the picture data, based on the following parameters, which were considered for 7 different amplitude intervals: 1) the extension of image areas marked by amplitude bands of interest, 2) the percentage of the image surface reflecting within a homogeneous amplitude band, 3) the number of objects composing the image, 4) the average object size, and 5) the "density" of the objects. For all parameters considered, marked differences between sclerotic skin and normal tissue were observable. When assessment is performed with amplitude bands covering the lower part of the scale, the image referring to sclerotic tissue appears relatively homogeneous with few, large objects within a thickened skin block, which occupy a more extended image surface in comparison to images of normal skin, characterized by spots, which are small and closely packed. On the contrary, binary images of morphea plaques transformed by intermediate to high amplitude intervals appear with fewer objects of approximately the same size or smaller, which are less compressed in respect to healthy skin images.

Adult↗