Clinical course of occupational irritant contact dermatitis of the hands in relation to filaggrin genotype status and atopy

Increased loss-of-function filaggrin gene mutation prevalence in atopic dermatitis patients across northern latitudes indicates genetic fitness: A systematic review and meta-analysis

Loss-of-function (LoF) mutations in the filaggrin gene (FLG) constitute the strongest genetic risk for atopic dermatitis (AD). A latitude-dependent difference in the prevalence of LoF FLG mutations was systematically evaluated. A systematic review and meta-analysis were performed to estimate the prevalence of LoF FLG mutations in AD patients and the general population by geography and ethnicity. Risk of bias was assessed by Newcastle-Ottawa Scale and Jadad score. StatsDirect, version 3 software was used to calculate all outcomes. PubMed and EMBASE were searched until 9th December 2021. Studies were included if they contained data on the prevalence of LoF FLG mutations in AD patients or from the general population or associations between AD and LoF FLG mutations and were authored in English. Overall, 248 studies and 229 310 AD patients and individuals of the general population were included in the quantitative analysis. The prevalence of LoF FLG mutations was 19.1% (95% CI, 17.3-21.0) in AD patients and 5.8% (95% CI, 5.3-6.2) in the general population. There was a significant positive association between AD and LoF FLG mutations in all latitudes in the Northern hemisphere, but not in all ethnicities. The prevalence of LoF FLG mutations became gradually more prevalent in populations residing farther north of the Equator but was negligible in Middle Easterners and absent in most African populations. FLG LoF mutations are common and tend to increase with northern latitude, suggesting potential clinical implications for future AD management. The existence of possible genetic fitness from FLG LoF mutations remains unknown.

Irritant Contact Dermatitis — a Review

Purpose of Review

Recent Findings

Summary

A loss of function mutation in the filaggrin gene associated with ichthyosis vulgaris and rheumatoid arthritis

Introduction

Mutations in the filaggrin ( FLG) gene are known to cause ichthyosis vulgaris.

Methods

We used whole-genome sequencing (WGS) technology to investigate the genetic causes of rare and complex inherited diseases including rheumatoid arthritis, ichthyosis, and congenital fibrosis of the extraocular muscles type 1 (CFEOM1) in a Chinese family. WGS was performed in four topics, and the identified candidate mutations were further verified through Sanger sequencing.

Results

We identified a mutation in FLG gene (g.152280098 C>A, p.E2422∗) that may be associated with ichthyosis and arthritis. Moreover, a mutation in KIF21A (g.39726207 G>A, p.R954 W) was also determined in affected members as the cause of CFEOM1. The gene interaction network demonstrated an interesting correlation between FLG and genes associated with arthritis and ichthyosis. Functional enrichment analysis of these interacting genes revealed several possible pathways that might be linked to arthritis and ichthyosis.

Conclusion

In general, we confirmed a loss of function mutation in the FLG gene associated with ichthyosis vulgaris and rheumatoid arthritis in this family.

Effectiveness of secondary prevention in metalworkers with work-related skin diseases and comparison with participants of a tertiary prevention program: A prospective cohort study

BACKGROUND

In Germany, a multistep approach has been established to prevent work-related skin diseases (WRSDs).

OBJECTIVES

To evaluate the effect of a secondary individual prevention program (SIP) in metalworkers with WRSD and to compare their characteristics with those of participants of a tertiary individual prevention program (TIP).

PATIENTS AND METHODS

In a prospective cohort study, metalworkers with WRSD of the hands participating either in the SIP (n = 114) or in the TIP (n = 83) were recruited. At baseline and at the respective follow-up 8-12 weeks after the SIP or at dismissal from the TIP (3-4 weeks later), questionnaires were completed and the severity of WRSD was assessed. Saliva samples were collected for assessment of filaggrin (FLG) mutations and an explorative genome-wide association study (GWAS).

RESULTS

Ninety-three SIP patients (81.6%) attended the follow-up. Disease severity was significantly reduced, and knowledge and protective behavior were significantly improved compared to baseline. Significant differences between SIP and TIP patients were found regarding duration and severity of symptoms, work absenteeism, tobacco smoking, and presence of atopic dermatitis, but not regarding FLG mutations and by GWAS.

CONCLUSIONS

The SIP was effective in metalworkers with WRSDs. Individual factors may influence the course of the disease and the need for the TIP.

Genetic variants of filaggrin are associated with occupational dermal exposure and blood DNA alterations in hairdressers

Hairdressers are exposed to high levels of chemicals, including possible carcinogens. For dermal exposure, the skin protects against the uptake of chemicals and the protein filaggrin (encoded by FLG) has a key role in skin barrier function. This study investigated if variants of FLG previously linked to impaired skin barrier function, i.e. null mutations and copy number variation (CNV) alleles (CNV10), are associated with cancer-related DNA changes. Blood and questionnaire data were collected from hairdressers (n = 295) and controls (n = 92). Exposure to aromatic amines was measured as hemoglobin adducts by gas chromatography tandem mass spectrometry. DNA from peripheral blood was used to test for FLG null mutations and CNV (10, 11, or 12 repeats), telomere length, and methylation of selected cancer-related genes. Hairdressers had a lower frequency of FLG null mutations (4.1 vs. 7.6%, P = 0.18) and CNV10 (43.2 vs. 56%, P = 0.0032) than controls. In hairdressers, CNV10 carriers had a decreased risk of high ortho-toluidine adducts in blood compared with non-carriers (odds ratio, OR = 0.49, 95% CI = 0.30-0.81). Further, telomere length was shorter for carriers of any FLG null allele (β = -0.18, 95% CI = -0.31 to -0.044) and CNV10 carriers (β = -0.054, 95% CI = -0.11 to -0.00051, linear regression adjusted for age, passive smoking, residence, and education) compared to non-carriers. Carriers of any FLG null allele showed higher methylation of the cyclin-dependent kinase inhibitor 2A gene CDKN2A (OR = 6.26, CI = 1.13-34.7), but not of the other genes analyzed. These associations were not found among the controls. Our study showed that the frequency of FLG CNV10 was lower among hairdressers than controls, which may indicate a healthy worker selection. Moreover, FLG null and CNV10 were associated with cancer-related DNA changes in hairdressers, which may influence their risk of cancer.

Association of FLG single nucleotide variations with clinical phenotypes of atopic dermatitis

Background

FLG encodes a large protein called profilaggrin, which plays a key role in maintaining an effective skin barrier against the environment. In this study, we identified FLG single nucleotide variations (FLG-SNVs) and evaluated the association of FLG-SNVs with clinical phenotypes including atopic dermatitis (AD)-associated minor clinical features, presence of specific allergic sensitization, and serum parameters.

Methods

Eighty-one Korean patients with AD were enrolled. AD-associated minor clinical features as well as allergic rhinitis and asthma were diagnosed by specialists. FLG-SNVs were identified by Sanger sequencing of entire exons through long-range PCR. Allergic sensitization to a specific allergen was evaluated by multiple allergen simultaneous test. Serologic parameters such as serum eosinophil cationic protein (ECP) and eosinophil derived neurotoxin (EDN) were measured.

Results

A total of seventy-three SNVs and 4 LOF mutations were successfully genotyped. rs71626704 and rs76413899 were significantly associated with a history of asthma and cheilitis (P = 0.002 and P = 0.033, respectively), however, the associations were not found statistically significant after adjustment by multiple comparisons. In addition, we detected haplotype blocks which were correlated with non-specific hand or foot dermatitis and scalp scale. We identified FLG-SNVs which were associated with sensitization to environmental allergens; rs62623409 and rs71625199 (P = 0.038 and P = 0.008, respectively). Patients with FLG P478S TT and history of allergic rhinitis showed a higher EDN level, and among those patients, the ones with asthma showed a higher ECP level.

Conclusion

This study revealed the association of FLG-SNVs with AD-associated minor clinical features. We firstly identified rs71625199 which was associated with higher environmental allergic sensitization. We also suggest that FLG P478S is a kind of disease modifier which affects serologic parameters such as EDN and ECP.

The impact of atopic dermatitis on work life - a systematic review

Atopic dermatitis (AD) has considerable multidimensional personal and societal costs. However, the extend to which the patient's work life is affected due to AD is more sparsely described in the literature. The objective of this review was to examine the impact on work life for patients with AD, with a specific focus on choice of education and occupation, sick leave, social compensations and change of job due to AD. A systematic literature search was performed in PubMed, EMBASE and Web og Science up to 7 February 2017 for articles on the impact on work life for patients with AD. Results were summarized taking several measures of study quality into account. The search identified twenty-three articles, whereof five studies assessed the influence of AD on educational or job choice, without any consistent conslusion, while eight of nine studies with respect to sick leave and two on disability pensions found AD to have a negative impact. Studies of change or loss of job and AD showed more diverse results, as not all studies documented a negative effect of AD on work life. Atopic dermatitis imposes a burden extending beyond personal, emotional and financial costs. This review strongly implies that AD affects sick leave, and though not fully clarified, possible also job choice, change or loss of job and even disability pensions for the more severe cases.

Contact dermatitis in the construction industry: the role of filaggrin loss-of-function mutations

BACKGROUND

A high prevalence of contact dermatitis (CD) and respiratory symptoms has been observed in the construction industry, probably due to widespread exposure to irritants and allergens. It is unknown whether carriers of loss-of-function mutations in the gene encoding filaggrin (FLG), a known risk gene for eczema and asthma, are at increased risk.

OBJECTIVES

To investigate associations of FLG mutations with CD and respiratory symptoms in Dutch construction workers.

METHODS

A questionnaire including items on dermal and respiratory symptoms such as wheeze, shortness of breath and asthma was administered to construction workers. Total and specific serum IgE was analysed by enzyme immunoassays. Four FLG loss-of-function mutations were genotyped. CD was diagnosed by a team of a dermatologist and a clinical occupational medicine specialist using photographs of the subjects' hands and self-reported questionnaire data.

RESULTS

Of the 506 participating workers, 6·3% carried at least one FLG mutation. Mild CD was diagnosed by the specialists in 34·0%, and severe CD in an additional 24·3%. CD was considered work related in 282 of 295 subjects (95·6%). Carriers of FLG variants had an increased risk of CD compared with subjects carrying wild-type alleles [mild CD: odds ratio (OR) 5·71, 95% confidence interval (CI) 1·63-20·06; severe CD: OR 8·26, 95% CI 2·32-29·39]. FLG variants and the presence of CD were not associated with respiratory symptoms and atopy.

CONCLUSIONS

Contact dermatitis prevalence in construction workers is high. FLG loss-of-function mutations increase the risk of CD even further. FLG mutations were not associated with respiratory symptoms or atopy.

The hand eczema proteome: imbalance of epidermal barrier proteins

BACKGROUND

Chronic hand eczema (CHE) is a common skin disease with a high socioeconomic impact. While some light has been shed on the genetic factors that predispose individuals to the disease, little is known about its actual pathogenesis.

OBJECTIVES

We aimed to carry out a systematic and comprehensive analysis of the differential protein expression in CHE using modern mass spectrometry.

METHODS

We performed liquid chromatography with tandem mass spectrometry analyses and label-free quantification to analyse the proteomic profile of palmar skin from 12 individuals (six patients with hand eczema and six healthy volunteers). Immunohistochemistry of the palmar skin from seven different patients with hand eczema and seven different healthy volunteers was performed in a second step.

RESULTS

With this method we were able to identify 185 candidate proteins with a significantly different abundance in the hand eczema samples. Among them we found several barrier proteins: filaggrin (FLG), FLG-2 and hornerin were all downregulated in the hand eczema samples, as were the desquamation-related enzymes kallikrein-related peptidase (KLK)5 and KLK7 and cystatin E/M. The antimicrobial peptides S100A7 and S100A8/A9 and the small proline-rich protein 2B and S100A11 were upregulated in the diseased skin. Immunohistochemistry confirmed these findings.

CONCLUSIONS

Our results corroborate the assumption that skin barrier dysfunction plays an essential role in the pathogenesis of CHE.

Filaggrin loss-of-function mutations are not associated with atopic dermatitis that develops in late childhood or adulthood

BACKGROUND

The influence of filaggrin gene (FLG) mutations on early- vs. late-onset development of atopic dermatitis (AD), allergic contact dermatitis (ACD) and chronic irritant contact dermatitis (CICD) is not completely understood.

OBJECTIVES

To assess the association between FLG mutations and development of AD, ACD and CICD.

METHODS

This study assessed 241 patients with AD. AD developed during infancy in 85 patients, during childhood in 79 patients (32 early and 47 late) and during adulthood in 77 patients. We also included 100 patients with ACD and 44 with CICD, as well as 164 healthy controls. Four prevalent FLG loss-of-function mutations were genotyped (R501X, 2282del4, R2447X and S3247X).

RESULTS

The 2282del4 mutation was significantly associated with a greater risk of AD in the entire group [odds ratio (OR) 4·33, 95% confidence interval (CI) 1·26-14·96]. However, the 2282del4 mutation was associated only with AD that developed during infancy or in early childhood (≤ 8 years: OR 20·91, 95% CI 2·73-159·9), not with AD development in late childhood or adulthood (> 8 or > 18 years), or ACD or CICD. Similar associations were also observed for the combined 2282del4 or R501X genotype. Carriers of FLG mutations also experienced a longer duration of AD and required hospitalization more often.

CONCLUSIONS

FLG mutations are associated with only the early onset of AD, not late onset. Other factors should receive attention in patients with late-onset AD.

Contact dermatitis in the cleaning industry

PURPOSE OF REVIEW

The review summarizes recent findings on contact dermatitis in the cleaning industry.

RECENT FINDINGS

Contact dermatitis is still an important issue in cleaning. Recent studies identified cleaning work sites and tasks, as well as specific cleaning products, which incur a risk increase for occupational contact dermatitis in cleaning. Workers involved in cleaning outdoors prevalence ratio [PR 1.85, 95% confidence interval (CI) 1.16-2.96], cleaning common areas of residential buildings (PR 1.77, 95% CI 1.11-2.84), schools (PR 1.84, 95% CI 1.15-2.93) and cleaning building sites (PR 1.87, 95% CI 1.18-2.95) showed significantly higher rates of contact dermatitis. Relevant allergens in cleaning are rubber chemicals and disinfectants. Leading allergens are thiurams (11.6%, 95% CI 9.1-14.1) and formaldehyde (3.4%, 95% CI 2.0-4.7), but contact with metal allergens might also be important. The most likely allergen sources for sensitization against rubber chemicals are protective gloves. High sensitization rates for disinfectants might result from the fact that employees in cleaning often use single-use medical examination gloves while cleaning. These gloves are not resistant to chemicals, which may break through the gloves within a short period of time, depending on glove material and thickness. No differences in sensitization rates and sensitization profiles were seen in cleaners of younger (≤40 years) and older (>40 years) age.

SUMMARY

Prevalence of occupational contact dermatitis is still high in cleaning. Irritant contact dermatitis is prevailing, but allergic contact dermatitis is quite frequent, too. Up to now, prevention strategies in cleaning seem to be insufficient.

Occupational and non-occupational allergic contact dermatitis: a follow-up study

BACKGROUND/AIMS

The aim of this study was to obtain insight into the clinical course and prognosis of allergic contact dermatitis (ACD), including potential effects of genetic and environmental factors.

METHODS

Eighty-two patients with previously defined ACD acquired occupationally (OACD) or non-occupationally (NOACD) were patch retested and evaluated for the presence of persistent eczema, atopy and filaggrin mutations.

RESULTS

The crude risk for the persistence of a positive patch test (PT) reaction was 6.3 times higher (95% CI 3.63-11.0) for PT reactions assessed as '+++' compared to '++' reactions at the first PT. Among the categories of OACD, NOACD, age, gender, atopy, and the number of positive PT reactions at the first and second PT, only OACD (OR 10.0, 95% CI 1.95-51.2) and number of positive PT reactions at retesting (OR 3.85, 95% CI 1.57-9.44) were found to be predictors of persistent eczema.

CONCLUSIONS

Occupationally acquired contact allergy was emphasized as the most important factor in predicting poor prognosis of ACD.

Filaggrin loss-of-function mutations and atopic dermatitis as risk factors for hand eczema in apprentice nurses: part II of a prospective cohort study

Background/objectives

Environmental exposure and personal susceptibility both contribute to the development of hand eczema. In this study, we investigated the effect of loss-of-function mutations in the filaggrin gene (FLG), atopic dermatitis and wet work exposure on the development of hand eczema in apprentice nurses.

Methods

Dutch apprentice nurses were genotyped for the four most common FLG mutations; atopic dermatitis and hand eczema history were assessed by questionnaire. Exposure and hand eczema during traineeships were assessed with diary cards.

Results

The prevalence of hand eczema during traineeships was higher among subjects with a history of hand eczema reported at inclusion. Hand washing during traineeships and at home increased the risk of hand eczema. After adjustment for the effects of exposure and FLG mutations, an odds ratio of 2.5 (90% confidence interval 1.7–3.7) was found for a history of atopic dermatitis. In this study, an increased risk of hand eczema conferred by FLG mutations could not be shown, but subjects with concomitant FLG mutations and atopic dermatitis showed the highest risk of hand eczema during traineeships.

Conclusion

A history of atopic dermatitis, a history of hand eczema and wet work exposure were the most important factors increasing the risk of hand eczema during traineeships.