Pieter Jan Coenraads

The epidemiology of occupational contact dermatitis.

Occupational contact dermatitis (OCD) ranks first of all occupational diseases in many countries. The incidence rate is believed to be around 0.5-1.9 cases per 1000 full-time workers per year. Epidemiological studies play an important role in observing disease trends, analysing risk factors, and monitoring the effect of preventive measures. In this review article the lack of truly epidemiologic data on OCD and the difficulties of those studies are illustrated. The following issues are highlighted: case ascertainment and bias, the distribution of allergic and irritant contact dermatitis in the working population, the interrelationship between exogenous (allergens, irritants) and endogenous factors, the prognosis, the social and economic impact, and the need for intervention studies.

Efficacy and safety of oral alitretinoin (9-cis retinoic acid) in patients with severe chronic hand eczema refractory to topical corticosteroids: results of a randomized, double-blind, placebo-controlled, multicentre trial.

Background  Patients with severe chronic hand eczema (CHE) refractory to topical corticosteroids currently have limited treatment options suited for chronic use, and few controlled clinical studies have investigated new therapies in this setting.

Management of chronic hand eczema

Hand eczema (HE) is one of the most frequent skin diseases and has often a chronically relapsing course with a poor prognosis resulting in a high social and economic impact for the individual and the society. In this article, we highlight the results of an expert workshop on the ‘management of severe chronic hand eczema’ with the focus on the epidemiology, the burden of severe HE, its classification and diagnostic procedures, and the current status of treatment options according to an evidence‐based approach (randomized controlled clinical trials, RCTs). We conclude that despite the abundance of topical and systemic treatment options, disease management in patients with severe chronic HE is frequently inadequate. There is a strong need for RCTs of existing and new treatment options based on clearly diagnosed subtypes of HE and its severity.

Susceptibility to irritants: role of barrier function, skin dryness and history of atopic dermatitis

The susceptibility of the skin to various irritants was investigated with the aim of determining the role of the barrier function of the stratum corneum, skin dryness and whether a history of atopic dermatitis (AD) was a factor. The transepidermal water loss (TEWL) was measured using an evaporimeter and skin hydration using a Corneometer and by visual scoring. The group with a history of AD (n= 20) had a lower pre‐exposure barrier function and a higher TEWL value following irritant exposure than the group with a history of allergic contact dermatitis (n= 18) and a control group (n= 18). Clinically dry skin was more susceptible than normal skin, though no difference was noted in the pre‐exposure barrier function. The increased susceptibility to irritants in those with a past history of AD was probably due to impaired barrier function. The increased susceptibility to irritants in those with a past history of AD was probably due to impaired barrier function and/or the presence of a dry skin.

The European baseline series in 10 European Countries, 2005/2006 : results of the European Surveillance System on Contact Allergies (ESSCA)

Background: Continual surveillance based on patch test results has proved useful for the identification of contact allergy.

Prevalence, incidence and course of eczema on the hands and forearms in a sample of the general population

In 1979, the inhabitants of a geographically defined area were examined for skin disorders of the hands and forearms. In 1982 this cohort was invited for re‐examination. In persons with eczema, patch testing was performed. Irritant factors were found to play a rôle in 73% of the cases, whereas a contact allergy could be detected in 30%. The must frequent allergens were nickel sulphate (20%), potassium dichromate (6%), land cobalt chloride (4%). In some persons with a definite history of allergy to metals, no positive patch test with nickel, chromate or cobalt could be obtained; other mechanisms may be involved. Significantly more positive patch tests were found among persons with an eczema of longer than 2 years duration compared with persons, with eczema present for a shorter period of time, indicating that many cases of eczema are primarily of irritant nature, but later complicated by sensitisation.

Evaluation of a self‐administered questionnaire on hand dermatitis

The purpose of the study was to evaluate a sell‐administered questionnaire on hand dermatitis than was developed to identify persons with hand dermatitis in epidemiological studies. A total of 109 nurses were subject to dermatological examination of the hands within 1 month of returning the questionnaire. 2 types of questionnaire diagnoses were made: a ‘symptom‐bused’ diagnosis and a ‘self‐reported diagnosis’. These were compared to the medical diagnosis of hand dermatitis. The prevalence of hand dermatitis in the 12 months before the study, based on the medical diagnosis, was 18.3%. The prevalence according to the symptom‐based diagnosis and the self‐reported diagnosis was 47.7% and 17.4%. respectively. The sensitivity and specificity of the symptom‐based diagnosis were 100% and 64%, respectively. It is concluded that the symptom‐based diagnosis can be used as screening instrument for the detection of cases in large study populations, if followed by dermatological examination of persons with a positive diagnosis. The sensitivity and specificity of the self‐reported diagnosis were 65% and 93%, respectively. It is concluded that the self‐reported diagnosis can be used to obtain a rough estimate of the prevalence, although comparison of prevalence figures between study populations may be distorted due to a difference in reporting of hand dermatitis. The results of the study illustrate the size of the differences in prevalence estimates that may arise as a result of differences in the definition and method of diagnosing hand dermatitis.

Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

This is one of series of review articles on formaldehyde and formaldehyde‐releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty‐five chemicals were identified as being formaldehyde‐releasers. Although a further seven are listed in the literature as formaldehyde‐releasers, data are inadequate to consider them as such beyond doubt. Several (nomenclature) mistakes and outdated information are discussed. Formaldehyde and formaldehyde allergy are reviewed: applications, exposure scenarios, legislation, patch testing problems, frequency of sensitization, relevance of positive patch test reactions, clinical pattern of allergic contact dermatitis from formaldehyde, prognosis, threshold for elicitation of allergic contact dermatitis, analytical tests to determine formaldehyde in products and frequency of exposure to formaldehyde and releasers. The frequency of contact allergy to formaldehyde is consistently higher in the USA (8–9%) than in Europe (2–3%). Patch testing with formaldehyde is problematic; the currently used 1% solution may result in both false‐positive and false‐negative (up to 40%) reactions. Determining the relevance of patch test reactions is often challenging. What concentration of formaldehyde is safe for sensitive patients remains unknown. Levels of 200–300 p.p.m. free formaldehyde in cosmetic products have been shown to induce dermatitis from short‐term use on normal skin.

PREVALENCE OF ECZEMA AND OTHER DERMATOSES OF THE HANDS AND ARMS IN THE NETHERLANDS - ASSOCIATION WITH AGE AND OCCUPATION

In a sample of about 3000 adults the hands and arms were examined for the presence of skin disorders. The most important diagnostic category was eczema; prevalence among males was 4.6% and among females it was 8%. In the majority of patients with eczema irritant factors were found to play a role. Among males occupation was a major factor associated with prevalence of eczema. After correction for occupation there remained no association with age.

Prediction of susceptibility to an irritant response by transepidermal water loss

The roles of the natural permeability of the stratum corneum to water, and the changes in that permeability effected by a single patch test, were investigated as parameters to predict the susceptibility of the skin to repeated exposures of an irritant. One site on the forearm skin of 27 non‐atopic healthy subjects was exposed to a 0.5% concentration of sodium lauryl sulphate by a single occlusive 24‐h patch. Another site was exposed to a twice daily 4‐day repeated occlusive patch with the same irritant solution. The effects were evaluated by transepidermal water loss measurements made prior to the applications (baseline) on day 1 (BASE), following the single 24‐h patch on day 2 (SINGL), and following the 4‐day repeated applications on day 5 (REPET). Individuals with higher BASE had higher SINGL (R= 0.80, P < 0.001) and higher REPET (R= 0.76, P < 0.001). There was also a significant linear correlation between SINGL and REPET (R= 0.63, P < 0.001). Multiple linear regression analysis of results, however, indicated that a high baseline TEWL is a better indication of an individuals increased susceptibility (high REPET) to weak irritants than a high TEWL value following a single 24‐h patch test. Baseline TEWL may therefore be used as a reasonably accurate preliminary “predictive” screening test for susceptibility to irritants.