Patch and prick test study of 593 healthy subjects

593 recruits selected by the Military Health Service as being healthy and without a history of present or previous dermatitis, or ocular refraction defects, were patch tested with the GIRDCA (Italian Research Group on Contact and Environmental Dermatitis) standard series. Of these, 336 were also patch tested with substances used in the processing and dyeing of textiles and prick tested with 8 major allergens. 74 (12.5%) reacted to 1 or more substances. The most frequent sensitizers were: thimerosal (28 cases), ammoniated mercury (7 cases), phenol-formaldehyde resin (6 cases), parabens, nickel and Disperse Red 17 (4 cases each). 113 recruits reacted to 1 or more prick test allergens. We have demonstrated the importance of establishing such reference values in healthy groups for the correct evaluation of data collected from selected groups.     

Patch testing in discoid eczema

We report a retrospective study of patch testing in patients with discoid eczema. 48 patients with persistent or severe discoid eczema were patch tested. The mean age of patients was 45 years and the median duration of symptoms was 6 months. 24 patients (50%) had positive patch tests, and 16 of these (33%) were considered to be clinically relevant. The most common allergens implicated were rubber chemicals, formaldehyde, neomycin, chrome, nickel (5, 2, 2, 2, 2, 2 reactions, respectively). 13 of 16 patients were followed up by telephone in 1996, and 8/13 (61%) slated they had benefited from patch testing. This study suggests allergic contact dermatitis is relatively common in persistent discoid eczema, and allergen avoidance may be of benefit. We recommend patch testing should be considered for all patients with severe or persistent discoid eczema.     

Patch testing in discoid eczema

Fifty patients of both sexes with clinically suspected discoid eczema were patch tested with the Indian Standard Patch Test Battery approved by the Contact and Occupational Dermatosis Forum of India (CODFI). Most of these patients were young adults between 20 and 39 years old, with a mean age of 36 years. The mean duration of symptoms was 21/2 years. The occupational profiles of the patients included farmers (24%), housewives (18%), students (14%), housewives engaged in farming (12%), shopkeepers (10%), and laborers (8%). The miscellaneous group, including technicians, drivers, cable operators, office workers, and computer operators, accounted for the remaining 14%. The common clinical patterns of presentation of discoid eczema included hands and feet (44%), hands and forearms' (30%), legs and feet (12%) and trunk and limbs (12%). Patch test analysis of these patients revealed that, out of the 50 subjects tested, 28 (56%) reacted to one or more allergens. Potassium dichromate was the most common allergen (20%), followed by nickel (16%), cobalt chloride, and fragrance (12% each) in decreasing order of frequency. Hence, it may be concluded that patch testing should be considered for all patients with severe or persistent discoid eczema because allergic contact dermatitis may be relatively common in such patients and the avoidance of offending allergens may be of substantial benefit to the patients.     

Patch testing is a useful investigation in children with eczema

Background. Allergic contact dermatitis in children is less recognized than in adults. However, recently, allergic contact dermatitis has started to attract more interest as a cause of or contributor to eczema in children, and patch testing has been gaining in recognition as a useful diagnostic tool in this group. Objectives. The aim of this analysis was to investigate the results of patch testing of selected children with eczema of various types (mostly atopic dermatitis) attending the Sheffield Children's Hospital, and to assess potential allergens that might elicit allergic contact dermatitis. Patients and methods. We analysed retrospectively the patch test results in 110 children aged between 2 and 18 years, referred to a contact dermatitis clinic between April 2002 and December 2008. We looked at the percentages of relevant positive reactions in boys and girls, by age groups, and recorded the outcome of treatment following patch testing. Results. One or more positive allergic reactions of current or past relevance was found in 48/110 children (44%; 29 females and 19 males). There were 94 allergy‐positive patch test reactions in 110 patients: 81 had a reaction of current or past relevance, 12 had a reaction of unknown relevance, and 1 had reaction that was a cross‐reaction. The commonest allergens with present or past relevance were medicaments, plant allergens, house dust mite, nickel, Amerchol® L101 (a lanolin derivative), and 2‐bromo‐2‐nitropropane‐1,3‐diol. However, finding a positive allergen was not associated with a better clinical outcome. Conclusions. We have shown that patch testing can identify relevant allergens in 44% of children with eczema. The commonest relevant allergens were medicament allergens, plant allergens, house dust mite, nickel, Amerchol® L101, and 2‐bromo‐2‐nitropropane‐1,3‐diol. Patch testing can be performed in children as young as 2 years with the proper preparation.     

Patch testing with benzoyl peroxide: reaction profile and interpretation of positive patch test reactions

Background: Patch testing with benzoyl peroxide 1% pet. frequently leads to (weak) positive reactions, often with uncertain clinical relevance.
Objectives: To describe the pattern of patch tests reactions to benzoyl peroxide and to identify patients at risk of a positive reaction.
Methods: Retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK), 1992–2007.
Results: Benzoyl peroxide 1% pet. was tested in 29 758 patients. Weak positive reactions (erythema, infiltration, possibly papules) occurred in 6.5%, and strong positive reactions (erythema, infiltration, vesicles) in 1.3%. According to logistic regression analysis, strong positive reactions to benzoyl peroxide were associated with leg or face dermatitis, work as dental technicians, young age and being female. Patients with atopic dermatitis had a significantly increased risk of weak positive reactions only.
Conclusions: Our analysis confirms that benzoyl peroxide 1% pet. is a problematic patch test preparation. Hence, clinical relevance of reactions to benzoyl peroxide has to be assessed very carefully. Patients with atopic dermatitis are particularly prone to irritant reactions to benzoyl peroxide. True allergic reactions may occur in dental technicians and following the treatment of leg ulcers with highly concentrated benzoyl peroxide in past. In contrast, widely used acne treatments with benzoyl peroxide seems to sensitize only rarely.     

Patch testing in Japanese subjects

Experience with various patch tests, usage tests, and other studies on Japanese and Caucasian subjects is presented. Differences between the races are noted by their responses.     

Patch test with ether extracts in salicaceae allergy

A total of 23 cases suggestive of airborne contact dermatitis were patch tested with ether extracts of flowers and leaves of populus sp. and salix sp. in a study conducted in Ladakh at an altitude of 3445 meters above sea level. Overall positivity was found in 12 (52.17%), with populus sp. alone in 7 (30.43%), salix sp. alone in 4 (17.39%) and to both in one (8.33%).     

Patch test results in schoolchildren

Our aim was to explore the current spectrum of contact allergens in schoolchildren, as a basis for diagnosis and prevention of allergic contact dermatitis. Results of patch tests in children 6–15 years old, performed in the years 1990–1995 by 22 centres of the German Contact Dermatitis Research Group and filed by the Information Network of Departments of Dermatology, were analysed and evaluated retrospectively, including epidemiologic data. Children with positive tests (62 out of 156 boys and 108 out of 260 girls tested) had a higher frequency of allergic contact dermatitis and a lower frequency of atopic dermatitis than patch test negative ones. 16 distinct allergens elicited positive reactions in 1% of the children tested. Reactions to nickel sulfate occurred in 15.9% of all children tested, but in 25.0% of girls 14/15 years old, and in only 4.5% of boys 6–13 years old. Double-sensitizations with cobalt salts, potassium dichromate and palladium were seen. Mercury compounds were found in 2nd place (thimerosal: all children: 11.3%; 6–13 years old: 14.3%, 14/15 years old: 8.0%), followed by fragrance allergens. We conclude that contact allergy in children is related to their sex and age. Prophylaxis against nickel, mercury, and fragrance allergy needs to be improved. A shortened standard series may be sufficient for testing children.