Reproducibility of atopy patch tests with Dermatophagoides: a study on 85 patients with atopic dermatitis

Atopy patch tests (APTs) are considered a useful addition to standard testing procedures for the identification of allergens triggering the appearance of eczema in patients with atopic dermatitis (AD). The aim of the study was to evaluate the reproducibility of APTs with house dust mites by simultaneously patch testing AD patients. 85 subjects affected by AD, 36 males and 48 females, aged from 1 to 52 years, were patch tested with Dermatophagoides mix (D. pteron/D. farinae) 20% pet. In our patients, the percentage of agreement between the frequency of positive and negative responses to Dermatophagoides mix was 96.7%. Reproducibility was highly satisfactory, as evaluated by k-value (0.953). As regards the agreement in the intensity of APT responses to Dermatophagoides mix between the right and left sides, we found that reproducibility was also highly satisfactory (k = 0.851). In conclusion, for Dermatophagoides APTs, the agreement rate was similar to that of standard patch tests, and therefore APTs may be considered sufficiently reproducible to be employed as a diagnostic testing procedure.     

Chronic actinic dermatitis: A clinical study of 15 cases in northern Taiwan

BackgroundChronic actinic dermatitis (CAD) is an idiopathic photosensitive dermatosis induced by ultraviolet B (UVB), sometimes ultraviolet A (UVA), and occasionally visible light. Diagnosis is suggested by the clinical findings, typically a chronic eczematous rash on the sun exposed areas, and confirmed by phototesting, which demonstrates the abnormal photosensitivity. The aim of this study was to determine the characteristics of CAD in Taiwanese patients.MethodsWe retrospectively reviewed the clinical and photobiological features of all patients diagnosed as having CAD at our institute from 2002 to 2012.ResultsA total of 15 patients with CAD were identified. The mean age at diagnosis was 58.6 years (range, 28–82 years). All the patients were males. The face, neck, forearms, and dorsal hands were most commonly involved. Eight patients (53.3%) had decreased minimal erythema dose (MED) to both UVB and UVA; six patients (40.0%) had decreased MED to only UVB; one patient (6.7%) had decreased MED to only UVA. All were managed with photoprotection and topical corticosteroids. Four patients received azathioprine (50 mg twice a day to every other day) and one received prednisolone (10 mg per day to every other day).ConclusionIn Taiwan, CAD affects elderly men more commonly. The most common phototest results were decreased MED to both UVB and UVA, followed by to UVB alone. All patients were managed with photoprotection and topical corticosteroids, and some also required systemic agents, in particular azathioprine.     

Standard patch test results in patients with contact dermatitis in Israel: age and sex differences

Previous studies have shown that the prevalence of specific allergens varies by geographic area, population, age and sex. The objective of the present study was to determine the relative frequency of positive reactions to different sensitizers in Israeli patients with clinically suspected contact dermatitis (CD) and to identify possible sex and age differences. A total of 943 consecutive patients were tested for CD using the European standard patch test series. The most frequent allergen was nickel sulfate followed by potassium dichromate and fragrance mix. Positive reactions to nickel sulfate were more common among women, especially those in the younger age group (younger than 40 years). Positive reactions to balsam of Peru were more common among men, especially those in the older age group (40 years or older). This study presents the result of the standard patch test in Israel with stratification according to age and sex. The findings of the present study, combined with reports on geographic/population differences in the prevalence of specific allergens in CD, indicate the need for further investigations to identify prominent local allergens for better adaptation of the standard patch test to local needs.     

Relevance of positive patch test reactions in patients attending a dermatology tertiary referral centre

Our purpose was to determine the proportion of relevant patch test reactions among all patch tested patients in the National Skin Centre (NSC), Singapore, from 1 January 1999 to 31 December 2000. A retrospective study was made of the patch test records of all patients patch tested in the study period. The proportion of relevant patch tests in this population was then determined. The allergens most likely to have present or past relevance were: nickel sulfate (79%), p-phenylenediamine (76%), colophonium (73%), cobalt chloride (68%) and potassium dichromate (67%). The most common allergens for each of the following relevance categories were as follows - present: p-phenylenediamine, thiuram mix, potassium dichromate; past: colophony, nickel sulfate, cobalt chloride; exposed: neomycin, gold sodium thiosulfate, fragrance mix and unknown: gold sodium thiosulfate, potassium dichromate, cobalt chloride. Evaluating relevance is difficult, and the results of relevance scoring vary widely between different groups. A consensus on the definition and standardization of the concept of relevance is needed.     

Allergic contact dermatitis in patients with frontal fibrosing alopecia: An international multi‐center study

Frontal fibrosing alopecia (FFA) mainly affects the anterior hairline and eyebrows and its etiology and associated factors remain obscure. The aim of this study was to evaluate the allergic contact dermatitis with patch test in patients with FFA. In this prospective study, 20 patients with FFA and 24 age and sex‐matched healthy individuals were evaluated with patch testing. Diagnosis was made histologically, clinically and based on dermoscopic findings. Demographic data, age of onset, disease duration and FFA severity index are evaluated in all patients. Positive patch test reaction to one or more allergen was observed in 65% of patients while it was 37.5% in control group (P = .003). There was a significant difference between age (P = .006) and positive patch test results. No statistical significant difference was observed in the results of patch testing and disease duration (P = .519), menopausal status (P = .085), and FFA severity index (P = .573). Our findings suggest an association between FFA and allergic contact dermatitis. The utility of patch testing in FFA patients can explore the role of allergic etiology and may have an enormous impact on the diagnostic potential and quality of life of these patients.     

Long-lasting allergic patch test reactions: a study of patients with positive standard patch tests

The purpose of this study was to determine the duration of patch test reactions and the frequency of long-lasting allergic patch test reactions (LLAPTR), and to identify the possible factors related to the development of the LLAPTR. For this purpose, a group of 263 patients positive to 1 or more allergens in the GIRDCA standard series was recruited. Readings were made for each patient 2 and 3 days after patch test application and continued every 2nd and 3rd day until the disappearance of all palpable erythema. The % of LLAPTR out of the total of reactions was high: 17.9%). Kathon CG was the hapten that caused LLAPTR most frequently, with 16 cases, a frequency of 76.1%), and a mean duration of the patch test reactions of 25.4 days. Risk factors investigated were age, sex, atopy, intensity of the patch test reaction and sensitivity to some allergens with the greatest number of positive patch tests. The relative importance of each risk factor was calculated by multivariate stepwise logistic regression analysis. It was found that a Kathon CG sensitivity was the most important risk factor for LLAPTR. 2nd was atopy, followed by strong patch test reaction. Rejected risk factors were sex, age and sensitivity to nickel sulfate, potassium dichromate, Disperse Blue 124, fragrance mix and p-phenylenediamine.     

A clinical and patch test study of patients with positive patch test reactions to fragrance mix in China

The clinical and patch test (PT) features of patients with positive PT reactions to fragrance mix (FM) were studied. 378 consecutive eczema outpatients patch tested with a modified European standard series were analysed. 60 patients (15.9%) reacted to FM. No significant differences could be found between the ages of FM PT-positive and PT-negative patients [median age 40.5 (range from 18 years to 69 years) versus median age 37.5 (range from 5 years to 81 years), rank sum test, P = 0.301]. FM PT-positive rate in confirmed non-cosmetic allergic contact dermatitis patients was 30.4%, which was similar to that in confirmed cosmetic allergic contact dermatitis patients (30.4% versus 30%, chi(2) test, chi(2) = 0.0010, P = 0.972). The FM PT-positive rates were 10.8% in males and 18.2% in females (chi(2) test, chi(2) = 3.3443, P = 0.067). 76.7% of the patients with fragrance contact dermatitis were allergic to Chinese traditional medicine, which is much higher than that for cosmetic allergy (76.7% versus 43.3%, chi(2) test, chi(2) = 6.9446, P = 0.008). The positive PT rate to colophonium in the patients with positive PT reactions to FM is higher than that in the FM PT-negative patients (18.9% versus 3.0%, chi(2) test, chi(2) = 15.5471, P < 0.01). 62.5% of the patients reacted to colophonium were positive to FM. These results show that age has little effect on fragrance contact allergy. Other fragrant products besides cosmetics are also important sources of fragrance contact allergy. Chinese traditional medicine was an important factor in fragrance allergy in China. Patients with positive PT reactions to FM are more likely to react to colophonium.     

The purpuric patch test in patients with allergic contact dermatitis from azo dyes

The histopathological features of the purpuric patch test have been described in individual cases only. We report a series of patients with allergic contact dermatitis, who developed purpuric patch tests at the sites of allergens from the azo dye group. 105 patients were clinically evaluated and tested with the TRUE Test and the textile color & finish series (Chemotechnique Diagnostics) because of suspected clothing dermatitis. Positive results to the latter were found in 31 patients (29.5%). In 9 of these, purpuric patch tests were observed at the sites of the allergens Disperse Blue 124, 106 and 85. 10 biopsies were performed and studied. The histopathological changes of the purpuric patch test included: spongiosis (in 90% of cases), exocytosis (70%), and dilated blood vessels (100%) without signs of vasculitis, surrounded by an inflammatory infiltrate composed mainly of T lymphocytes. Extravasated erythrocytes were seen perivascularly, but also in the interstitium, surrounding the acrosyringium, at the dermoepidermal junction, and in the epidermis. Increased number of mast cells were found in 22.2% of cases. Disperse Blue 124, 106, and 85 are potent allergens that can elicit purpuric patch test reactions. The purpuric patch test in our cases was a manifestation of an allergic reaction, based not only on histopathological changes, but also on evolution and relevance of the patch tests.     

Cosmetic dermatitis in Chinese eczema patients patch tested with a modified European standard series of allergens

The prevalence of cosmetic allergic contact dermatitis (CACD) in Chinese eczema patients (CEP) has not been reported. The purpose of our study was to analyse CACD in CEP and examine the frequency of patch test (PT) reactions to common cosmetic-related allergens (CRA). 378 consecutive CEP patch tested with a modified European standard series of allergens during a 2-year period in our clinic were analysed. 73 patients (19.3%) were considered as suspected CACD and 37 patients (9.8%) were confirmed. The frequencies of the positive PT reactions in suspected CACD and confirmed CACD to at least 1 CRA were 64.4% and 89.2%, to para-phenylenediamine (PPD) were 31.5% and 59.5%, to fragrance mix (FM) were 27.4% and 32.4% and to imidazolidinylurea were 5.5% and 8.1%, respectively. These results were much higher than those of CEP without cosmetic reactions (26.3% for at least 1 CRA, 5.8% for PPD, 8.8% for FM, and 0 for imidazolidinylurea) (P < 0.01 for all, Chi-square test and Fisher's exact test). These results suggested that CACD is very common in CEP patch tested. PPD and FM are the leading allergens identified. CACD should be strongly considered in CEP with positive PT reactions to PPD, FM and imidazolidinylurea.     

Patch testing in Israeli children with suspected allergic contact dermatitis: A retrospective study and literature review

Background/objectives

Childhood allergic contact dermatitis is recognized as a significant clinical problem. The objective was to evaluate the rate of positive patch tests in Israeli children with clinically suspected allergic contact dermatitis, identify possible sex and age differences, compare results with those in Israeli adults, and review pediatric studies in the literature.

Methods

The study sample included 343 children and adolescents (197 female, 146 male; 1‐18 years of age, mean age 11.8 years) with clinically suspected allergic contact dermatitis who underwent patch testing with a standard pediatric series of 23 allergens at a tertiary medical center from 1999 to 2012. Data on clinical characteristics and test results were collected retrospectively from the medical files.

Results

Ninety‐eight subjects (28.6%) (75 girls [38.1%], 23 boys [15.8%]) had at least one positive reaction. The most frequent reactions were to nickel sulfate, followed by potassium dichromate and cobalt chloride. Nickel sulfate sensitivity was more common in girls, especially those younger than 3 years and older than 12 years. The prevalence of contact sensitization was similar in subjects with and without atopic dermatitis (50% and 51%, respectively).

Conclusion

Nickel is the most common allergen in Israeli children, especially girls. Patch testing should be performed in children with clinically suspected allergic contact dermatitis regardless of atopic background.