Berit C. Carlsen

The association between null mutations in the filaggrin gene and contact sensitization to nickel and other chemicals in the general population

Background  It was recently shown that filaggrin gene (FLG) null mutations are positively associated with nickel sensitization. We have hypothesized that histidine‐rich filaggrin proteins in the epidermis chelate nickel ions and prevent their skin penetration and exposure to Langerhans cells. Furthermore, we have proposed that the low degree of genetic predisposition to nickel sensitization found by a Danish twin study was explained by a high prevalence of ear piercing among participants resulting in ‘bypassing’ of the filaggrin proteins.

Filaggrin null mutations increase the risk and persistence of hand eczema in subjects with atopic dermatitis: results from a general population study

Summary Background  Hand eczema is prevalent in the general population. It remains unclear whether or not filaggrin gene (FLG) null mutations increase the overall risk of hand eczema or only increase the risk of hand eczema in subjects with atopic dermatitis.

Prevalence of nickel and cobalt allergy among female patients with dermatitis before and after Danish government regulation: a 23-year retrospective study.

BACKGROUND An increased prevalence of nickel allergy prompted the Danish government to prohibit excessive nickel release (ie, >0.5 microg nickel/cm(2)/wk) from consumer products in 1990. Concomitant allergy to nickel and cobalt is often observed among patients with dermatitis, probably as a result of cosensitization. OBJECTIVES The study investigated the development of nickel and cobalt allergy among Danish female patients with dermatitis tested between 1985 and 2007. This was done to examine whether Danish nickel regulation has reduced the prevalence of nickel allergy and to examine whether the prevalence of cobalt allergy has increased as a result of the nickel regulation. METHODS A retrospective analysis of all patch test data from our database was performed (n = 10,335). Comparisons were made using a chi-square test for trend. Logistic regression analyses were used to test for associations. RESULTS The prevalence of nickel allergy decreased significantly among those aged 5 to 30 years from 27.6% in 1985 to 16.8% in 2007 (P(trend) < .002) but increased among those aged 31 to 49 years from 21.3% to 33.8% in the same period (P(trend) < .001). The median age was significantly higher among patients with isolated cobalt allergy than among patients with nickel allergy (P < .001). LIMITATIONS No information on causative exposures was available. CONCLUSIONS Nickel allergy decreased among young female patients with dermatitis between 1985 and 2007 whereas it increased among older patients, probably as a result of a cohort effect. The prevalence of cobalt allergy remained relatively unchanged.

20 Years of standard patch testing in an eczema population with focus on patients with multiple contact allergies

Results of standard patch tests performed with the same methodology in one centre are rarely available over a large time span. This gives the unique opportunity to study not only prevalence but also persistency of contact allergy and characterize subpopulations. The objectives were to investigate sensitivity rates and persistencies of patch test results and characterize patients with multiple contact allergies. A 20‐year retrospective database‐based study of 14 998 patients patch tested with the European Standard Series was performed. 34.5% were sensitized, primarily women. Sensitivity to nickel was most frequent and least frequent to mercaptobenzothiazole, N‐isopropyl‐N‐phenyl‐p‐phenylenediamine and benzocaine. Yearly proportion of negative, mono/double‐allergic, and multiple‐allergic cases remained stable. Persistency of positive reactions was high for para‐phenylenediamine, Cl(Me)isothiazolinone, and primin and poor for paraben mix. 5.1% were multiple allergic, primarily women, and 90% got diagnosed by the first test. Frequency of multiple allergies increased with age. More multiple‐ than mono/double‐allergic patients were tested multiple times. Persistency and sensitivity rates in a Danish eczema population are provided and are useful for decisions regarding the standard series. Patients with multiple contact allergies are typically elderly women who might have long‐lasting and hard‐to‐treat eczema. Cumulative environmental exposure seems necessary to develop multiple allergies.

The prevalence of chromium allergy in Denmark is currently increasing as a result of leather exposure

Background  Chromium allergy has traditionally been caused by occupational skin contact with cement. In 1983, Danish legislation made the addition of ferrous sulphate compulsory in cement to reduce the water‐soluble chromium content to not more than 2 ppm. An effect from this intervention has previously been demonstrated among Danish construction workers.

Nickel reactivity and filaggrin null mutations – evaluation of the filaggrin bypass theory in a general population

Background. It was recently shown that filaggrin null mutation carrier status was associated with nickel allergy and self‐reported intolerance to costume jewellery. Because of the biochemical characteristics of filaggrin, it may show nickel barrier properties in the stratum corneum.

Temporal trends of preservative allergy in Denmark (1985–2008)

Background: Most cosmetics and industrial products contain preservatives. Preservative allergy is common and, historically, changing contact allergy epidemics caused by preservatives have been observed. In 1997, Alan Dillarstone predicted a stable development of preservative allergy following mandatory ingredient labelling on cosmetic products.

Trends of contact allergy to fragrance mix I and Myroxylon pereirae among Danish eczema patients tested between 1985 and 2007

Background:  Fragrance contact allergy has for long been recognized as an important health issue. In Denmark, the frequency of fragrance mix (FM) I contact allergy increased between 1985–1986 and 1997–1998 among male and female dermatitis patients.

Filaggrin mutations are strongly associated with contact sensitization in individuals with dermatitis.

Background. Although heterozygous filaggrin gene (FLG) mutation carriers seem to have an increased risk of atopic, irritant and allergic nickel dermatitis, it remains unclear whether the risk of contact sensitization to allergens other than nickel is also elevated in FLG mutation carriers.

Patients with multiple contact allergies: a review.

Patients with multiple contact allergies, also referred to as polysensitized, are more frequent than predicted from prevalence of single sensitivities. The understanding of why some people develop multiple contact allergies, and characterization of patients with multiple contact allergies is limited. This review presents the current knowledge on the topic and discusses the evidence and characteristics of an increased susceptibility factor, possible causes to and genetic markers for the increased susceptibility, composition of the patient group and identification of patients at risk of developing multiple contact allergies. Evidence of allergen clusters among polysensitized individuals is also reviewed. The literature supports the idea that patients with multiple contact allergies constitute a special entity within the field of contact allergy. There is no generally accepted definition of patients with multiple contact allergies. We suggest that contact allergy to 3 or more allergens are defined as multiple contact allergies.