Niels Henrik Nielsen

Gentofte Hospital , Hellebæk, Capital Region, Denmark

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Publications (16)111.92 Total impact

  • Source
    Article: Prevalence of allergic contact dermatitis caused by hydroxyisohexyl 3-cyclohexene carboxaldehyde has not changed in Denmark.
    Contact Dermatitis 07/2012; 67(1):49-51. · 3.51 Impact Factor
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    Article: Contact allergy to epoxy resin: risk occupations and consequences.
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    ABSTRACT: Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences. The dataset comprised 20 808 consecutive dermatitis patients patch tested during 2005-2009. All patients with an epoxy resin-positive patch test were sent a questionnaire. A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization to epoxy resin remained stable over the study period. Of the patients with an epoxy resin-positive patch test, 71% returned a questionnaire; 95 patients had worked with epoxy resin in the occupational setting, and, of these, one-third did not use protective gloves and only 50.5% (48) had participated in an educational programme. The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required.
    Contact Dermatitis 04/2012; 67(2):73-7. · 3.51 Impact Factor
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    Article: Deodorants are the leading cause of allergic contact dermatitis to fragrance ingredients.
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    ABSTRACT: Fragrances frequently cause contact allergy, and cosmetic products are the main causes of fragrance contact allergy. As the various products have distinctive forms of application and composition of ingredients, some product groups are potentially more likely to play a part in allergic reactions than others. To determine which cosmetic product groups cause fragrance allergy among Danish eczema patients. This was a retrospective study based on data collected by members of the Danish Contact Dermatitis Group. Participants (N = 17,716) were consecutively patch tested with fragrance markers from the European baseline series (2005-2009). Of the participants, 10.1% had fragrance allergy, of which 42.1% was caused by a cosmetic product: deodorants accounted for 25%, and scented lotions 24.4%. A sex difference was apparent, as deodorants were significantly more likely to be listed as the cause of fragrance allergy in men (odds ratio 2.2) than in women. Correlation was observed between deodorants listed as the cause of allergy and allergy detected with fragrance mix II (FM II) and hydroxyisohexyl 3-cyclohexene carboxaldehyde. Deodorants were the leading causes of fragrance allergy, especially among men. Seemingly, deodorants have an 'unhealthy' composition of the fragrance chemicals present in FM II.
    Contact Dermatitis 05/2011; 64(5):258-64. · 3.51 Impact Factor
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    Article: Fragrance mix II in the baseline series contributes significantly to detection of fragrance allergy.
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    ABSTRACT: Fragrance mix II (FM II) is a relatively new screening marker for fragrance contact allergy. It was introduced in the patch test baseline series in Denmark in 2005 and contains six different fragrance chemicals commonly present in cosmetic products and which are known allergens. To investigate the diagnostic contribution of including FM II in the baseline series by comparing it with other screening markers of fragrance allergy: fragrance mix I (FM I), Myroxylon pereirae and hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC). Retrospective study of 12 302 patients consecutively patch tested with FM II by members of the Danish Contact Dermatitis Group 2005-2008. FM II gave a positive patch test in 553 patients (4.5%), and in 72.2% of these patients the reaction was judged to be clinically relevant. FM II ranked second in detecting fragrance allergy, after FM I. If FM II had not been included as a screening marker in the baseline series, 15.6% (n = 202) of individuals with fragrance allergy would not have been identified by the other fragrance screening markers (FM I, M. pereirae or HICC). FM II contributes substantially to detecting fragrance allergy. It ranked second among the fragrance screening markers tested in the baseline series and detects individuals with an allergy who otherwise would not have been identified.
    Contact Dermatitis 11/2010; 63(5):270-6. · 3.51 Impact Factor
  • Article: The association between hand eczema and nickel allergy has weakened among young women in the general population following the Danish nickel regulation: results from two cross-sectional studies.
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    ABSTRACT: An association between nickel contact allergy and hand eczema has previously been demonstrated. In 1990, Denmark regulated the extent of nickel release in the ear-piercing process as well as nickel release from consumer products. This study aimed to evaluate the effect of the Danish nickel regulation by comparing the prevalence of concomitant nickel allergy and hand eczema observed in two repeated cross-sectional studies performed in the same general population in Copenhagen. In 1990 and 2006, 3881 18-69 year olds completed a postal questionnaire and were patch tested with nickel. Data were analysed by logistic regression analyses and associations were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). The prevalence of concomitant nickel contact allergy and a history of hand eczema decreased among 18-35-year-old women from 9.0% in 1990 to 2.1% in 2006 (P < 0.01). The association between nickel contact allergy and a history of hand eczema decreased in this age group between 1990 (OR = 3.63; CI = 1.33-9.96) and 2006 (OR = 0.65; CI = 0.29-1.46). Among older women, no significant changes were observed in the association between nickel contact allergy and hand eczema. Conclusions: Regulatory control of nickel exposure may have reduced the effect of nickel on hand eczema in the young female population.
    Contact Dermatitis 10/2009; 61(6):342-8. · 3.51 Impact Factor
  • Article: Nickel allergy in Danish women before and after nickel regulation.
    New England Journal of Medicine 06/2009; 360(21):2259-60. · 53.30 Impact Factor
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    Article: Characteristics of nickel-allergic dermatitis patients seen in private dermatology clinics in Denmark: a questionnaire study.
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    ABSTRACT: The use of nickel in certain consumer goods has been regulated in Denmark since 1990. The aim of this study was to reveal the clinical characteristics of nickel-allergic patients seen in seven private dermatology clinics and to identify current sources of nickel that may elicit nickel dermatitis. During 2006 to 2007, 634 patients with dermatitis aged 17-91 years were patch-tested and completed a questionnaire including a question about the occurrence of dermatitis following skin contact with ear-rings or ear-pins, watches, buttons or metal clasps (i.e. metal dermatitis). chi2 tests were applied to test for statistical significant differences. Analysis revealed a lower prevalence of nickel allergy among women in the youngest age group (17-22 years) in comparison with older age groups (23-34 years and 35-46 years) (p < 0.03). Most patients experienced metal dermatitis on the first occurrence be-tween 1975 and 1985. No new cases of metal dermatitis were identified after 1985. We conclude that nickel allergy has decreased among young females with dermatitis due to the nickel regulation.
    Acta Dermato-Venereologica 01/2009; 89(4):384-8.
  • Article: Is there a risk of active sensitization to PPD by patch testing the general population?
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    ABSTRACT: Para-phenylenediamine (PPD), a constituent of permanent hair dyes, may cause contact allergy in exposed individuals. It has previously been questioned whether a patch testing with PPD in population-based epidemiological studies is entirely safe. The Glostrup allergy studies patch tested the same cohort twice. In 1990, 567 persons were patch-tested and only one person had a (+) positive reaction to PPD. In 1998, 540 persons were re-invited to a new patch test and 365 (participation rate 68%) were re-tested. There were no positive reactions to PPD. These studies indicate that patch testing with PPD in individuals with no previous positive reactions to PPD or with only one previous positive reaction does not cause active sensitization and can be performed with minimal risk.
    Contact Dermatitis 09/2007; 57(2):133-4. · 3.51 Impact Factor
  • Article: Bullous erythema multiforme following herpes zoster and varicella‐zoster virus infection
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    ABSTRACT: Four cases of herpes zoster-induced bullous erythema multiforme (EM) are reported. Three patients presented with widespread skin lesions 10 to 14 days after an episode of thoracic herpes zoster. In these patients a high increase in varicella-zoster virus (VZV) antibody titer was detected, indicating secondary VZV infection. Histologic examinations of skin biopsy from a patient with widespread lesions (case 4) revealed a mixture of EM, toxic epidermal necrolysis and herpetic virus infection. VZV should be included in the list of infectious agents able to trigger EM and Stevens-Johnson syndrome.
    Journal of the European Academy of Dermatology and Venereology 09/2006; 11(2):147 - 150. · 2.98 Impact Factor
  • Article: Nickel sensitization and ear piercing in an unselected Danish population
    Niels Henrik Nielsen, Torkil Menné
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    ABSTRACT: The study aimed at evaluating nickel sensitization and ear piercing in an unselected population. A questionnaire and ready-to-apply patch tests (TRUE-Test) were mailed to 793 subjects, aged 15 to 69 years. A total of 567 (71.5% out of the 793) were patch tested. The tests were read 2 days after application. Nickel sensitization was diagnosed in 11.1% of the females and in 2.2% of the males. Independent of sex, old age was associated with a lower risk of nickel sensitization (p <0.01). The risk of nickel sensitization was independent of a history of flexural eczema (p>0.5). Ear piercing was more common in the young than in the older age groups, ranging from 30.5% to 0.0% in men, and from 91.5% to 42.9% in women, Sensitization lo nickel was found in 14.8% of those with pierced ears as compared to 1.8% among those without pierced ears. When adjusted for the effects of sex and age, the risk of nickel sensitization among those with pierced ears remained significantly increased and the odds ratio value was 4.5: the 95% confidence interval of the odds ratio value was 1.5 to 13.0. The study confirmed that nickel sensitization in the general population is common, particularly among women. Ear piercing is probably an important risk factor for nickel sensitization.
    Contact Dermatitis 04/2006; 29(1):16 - 21. · 3.51 Impact Factor
  • Article: Smoking might be a risk factor for contact allergy.
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    ABSTRACT: Contact allergy is a major public health problem in industrialized countries. Hitherto, known risk factors for contact allergy have mainly included increased exposure to allergens. There are no published data on the relation between smoking and contact allergy. To investigate the association between smoking and contact allergy. The study population comprised a cross-sectional, general population-based sample of 15- to 69-year-old persons living in Copenhagen, Denmark. A total of 1056 persons (73.6% of the invited) were given a patch test (TRUE test). Contact allergy was defined as a positive patch test result to at least 1 of 23 allergens. Nickel contact allergy was defined as a positive patch test reaction to nickel. Allergic nickel contact dermatitis was defined as a history of eczema on exposure to metallic objects and a positive patch test reaction to nickel. A detailed smoking history was obtained in a questionnaire. Contact allergy (adjusted odds ratio, 1.8; 95% CI, 1.2 to 2.9), nickel contact allergy (adjusted odds ratio, 2.7; 95% CI, 1.4 to 5.2), and allergic nickel contact dermatitis (adjusted odds ratio, 3.0; 95% CI, 1.5 to 6.2) were significantly associated with a smoking history of more than 15 pack-years. Moreover, these associations showed a significant dose-response relation, and they were independent of sex, age, and exposure to nickel, as reflected by a history of ear piercing. These data raise the hypothesis that smoking increases the risk of contact allergy. Further epidemiologic studies and investigations into the possible mechanisms are warranted.
    Journal of Allergy and Clinical Immunology 06/2003; 111(5):980-4. · 11.00 Impact Factor
  • Article: IgG antibodies against microorganisms and atopic disease in Danish adults: the Copenhagen Allergy Study.
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    ABSTRACT: Seropositivity to food-borne and orofecal microorganisms (hepatitis A virus, Helicobacter pylori, and Toxoplasma gondii ), which are considered to be markers of poor hygiene, has been reported to be associated with a lower prevalence of atopy. In contrast, colonization of the gut with Clostridium difficile, a potential intestinal bacterial pathogen, in early childhood may be associated with a higher prevalence of atopy. The objective of this study was to investigate the association between atopy and exposure to 2 groups of food-borne and orofecal microorganisms: (1) markers of a poor hygiene and (2) intestinal bacterial pathogens. A cross-sectional population-based study of 15- to 69-year-olds living in Copenhagen, Denmark, was carried out in 1990 to 1991. Atopy was defined as a positive test result for specific IgE to at least 1 of 6 inhalant allergens. Exposure to microorganisms was assessed as IgG seropositivity to microorganisms. Seropositivity to 2 or 3 markers of poor hygiene (hepatitis A virus, H pylori, and T gondii ) was associated with a lower prevalence of atopy (adjusted odds ratio, 0.5; 95% CI, 0.3 to 0.8). In contrast, seropositivity to 2 or 3 intestinal bacterial pathogens (C difficile, Campylobacter jejuni, and Yersinia enterocolitica ) was associated with a higher prevalence of atopy (adjusted odds ratio, 1.7; 95% CI, 1.2 to 2.6). Exposure to markers of poor hygiene was associated with a lower prevalence of atopy, whereas exposure to intestinal bacterial pathogens was associated with a higher prevalence of atopy. These findings raise the hypothesis that different groups of food-borne and orofecal microorganisms may have different effects on the risk of atopy.
    Journal of Allergy and Clinical Immunology 05/2003; 111(4):847-53. · 11.00 Impact Factor
  • Article: The association between contact allergy and hand eczema in 2 cross‐sectional surveys 8 years apart
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    ABSTRACT: Hand eczema is a recurrent chronic skin disease related to contact allergy and atopic dermatitis. When possible, efforts should be redoubled to eliminate provoking factors. Our objective was to assess changes in the prevalence of self-reported hand eczema and to evaluate the association between contact allergy and hand eczema among adult Danes before and after nickel exposure regulation in Denmark. In 1990 and 1998, random samples of 15–41-year-old persons were examined in 2 cross-sectional studies of the general population in Copenhagen, Denmark. The studies included questionnaires, patch and prick testing. From 1990 to 1998 the prevalence of a history of hand eczema increased significantly. This increase did not appear to be fully explained by changes in the prevalence of flexural eczema, prick test reactivity, patch test reactivity, and nickel allergy. In 1990, nickel allergy and allergic nickel contact dermatitis were significantly associated with a history of hand eczema among women. In 1998, these associations were not found. It can be concluded that, from 1990 to 1998, the prevalence of a history of hand eczema rose significantly. It was indicated that it might be possible to prevent the hand eczema related to nickel allergy by exposure regulation, public education or both.
    Contact Dermatitis 11/2002; 47(2):71 - 77. · 3.51 Impact Factor
  • Article: [Increasing prevalence of specific IgE against aeroallergens in an adult Danish population--two cross-sectional studies in 1990 and 1998].
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    ABSTRACT: There is evidence that the prevalence of respiratory allergy has increased in children in many countries. However, this evidence is largely based on questionnaire data, and little is known about similar trends in adults. We investigated whether the prevalence of specific IgE to aeroallergens had increased in an adult general population over an 8-year period. Two cross-sectional surveys were carried out in 1990 and 1998. A screening questionnaire on respiratory symptoms sent to random samples of 15-41-year-old subjects living in Copenhagen (Denmark) preceded both surveys. Random samples of responders were invited to a health examination, which included assessment of specific IgE to six common aeroallergens. Totals of 312 (74.6% of those invited) and 482 (53.4% of those invited) subjects were examined in 1990 and 1998, respectively. Serum samples from both surveys were analysed in 1999. The prevalence of specific IgE to at least one allergen increased significantly from 1990 to 1998 (26.5% versus 33.9%; odds ratio adjusted for sex, age, and season of examination, 1.63; 95% confidence interval, 1.15-2.32). This increase remained unexplained after adjustment for changes in questionnaire variables on life-style and home environment. The clinical significance of this increase was underlined by a corresponding increase in the prevalence of allergic rhinitis symptoms associated with specific IgE positivity. We found that the prevalence of specific IgE positivity to aeroallergens increased in an adult Danish general population from 1990 and 1998.
    Ugeskrift for laeger 09/2002; 164(35):4061-5.
  • Article: The association between contact allergy and hand eczema in 2 cross-sectional surveys 8 years apart.
    [show abstract] [hide abstract]
    ABSTRACT: Hand eczema is a recurrent chronic skin disease related to contact allergy and atopic dermatitis. When possible, efforts should be redoubled to eliminate provoking factors. Our objective was to assess changes in the prevalence of self-reported hand eczema and to evaluate the association between contact allergy and hand eczema among adult Danes before and after nickel exposure regulation in Denmark. In 1990 and 1998, random samples of 15-41-year-old persons were examined in 2 cross-sectional studies of the general population in Copenhagen, Denmark. The studies included questionnaires, patch and prick testing. From 1990 to 1998 the prevalence of a history of hand eczema increased significantly. This increase did not appear to be fully explained by changes in the prevalence of flexural eczema, prick test reactivity, patch test reactivity, and nickel allergy. In 1990, nickel allergy and allergic nickel contact dermatitis were significantly associated with a history of hand eczema among women. In 1998, these associations were not found. It can be concluded that, from 1990 to 1998, the prevalence of a history of hand eczema rose significantly. It was indicated that it might be possible to prevent the hand eczema related to nickel allergy by exposure regulation, public education or both.
    Contact Dermatitis 09/2002; 47(2):71-7. · 3.51 Impact Factor
  • Article: Have oral contraceptives reduced the prevalence of acne? a population-based study of acne vulgaris, tobacco smoking and oral contraceptives.
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    ABSTRACT: The prevalence of acne among adolescents appears to vary geographically. This study was therefore undertaken to describe the prevalence rate of acne among Danish adolescents and to study the possible influence of oral contraceptives (OC) and tobacco smoking on disease prevalence and severity. Both have been suggested to influence acne and are therefore potential confounders in studies of acne prevalence. A random sample of 186 15- to 22-year-old subjects participating in a population-based study of allergic diseases in Copenhagen County were also examined for acne. Questionnaire data on demographic variables, acne problems, smoking status and use of OC were recorded, and acne was graded according to the Leeds scale. The prevalence of clinical acne (Leeds score >1) was 40.7% for men and 23.8% for women (odds ratio, OR, acne vs. no acne: 0.46, 95% confidence interval, CI: 0.24-0.85). Acne was perceived as a personal problem by 37.6% of all subjects, and this was associated with clinical acne (OR: 5.5, 95% CI: 2.7-10.9). The use of OC was associated with a significantly lower prevalence of acne (OR: 0.32, 95% CI: 0.11-0.86), while the use of tobacco smoking was not significantly associated with acne (OR: 0.54, 95% CI: 0.17-1.78). In congruence with recent reports from other countries, the prevalence rate of acne among adolescents was found to be lower than previously described in older reports. In this population, the use of OC was associated with a lower prevalence of acne.
    Dermatology 01/2002; 204(3):179-84. · 2.05 Impact Factor

Institutions

  • 2009–2012
    • Gentofte Hospital
      Hellebæk, Capital Region, Denmark
    • Psykiatrisk Center Sct. Hans
      Roskilde, Zealand, Denmark
  • 2006
    • Bispebjerg Hospital, Copenhagen University
      Copenhagen, Capital Region, Denmark
  • 2003–2006
    • Glostrup Hospital
      • • Medical Department C
      • • Centre for Preventive Medicine
      Glostrup, Capital Region, Denmark
  • 2002
    • Roskilde University
      Roskilde, Zealand, Denmark