SummaryThe present guideline summarizes all aspects of patch testing for the diagnosis of contact allergy in patients suspected of suffering, or having been suffering, from allergic contact dermatitis or other delayed-type hypersensitivity skin and mucosal conditions. Sections with brief descriptions and discussions of different pertinent topics are followed by a highlighted short practical recommendation. Topics comprise, after an introduction with important definitions, materials, technique, modifications of epicutaneous testing, individual factors influencing the patch test outcome or necessitating special considerations, children, patients with occupational contact dermatitis and drug eruptions as special groups, patch testing of materials brought in by the patient, adverse effects of patch testing, and the final evaluation and patient counselling based on this judgement. Finally, short reference is made to aspects of (continuing) medical education and to electronic collection of data for epidemiological surveillance.

A substantial number of studies have investigated the prevalence of contact allergy in the general population and in unselected subgroups of the general population. The aim of this review was to determine a median prevalence and summarize the main findings from studies on contact allergy in the general population. Published research mainly originates from North America and Western Europe. The median prevalence of contact allergy to at least 1 allergen was 21.2% (range 12.5-40.6%), and the weighted average prevalence was 19.5%, based on data collected on all age groups and all countries between 1966 and 2007. The most prevalent contact allergens were nickel, thimerosal, and fragrance mix. The median nickel allergy prevalence was 8.6% (range 0.7-27.8%) and demonstrates that nickel was an important cause of contact allergy in the general population and that it was widespread in both men and women. Numerous studies demonstrated that pierced ears were a significant risk factor for nickel allergy. Nickel was a risk factor for hand eczema in women. Finally, heavy smoking was associated with contact allergy, mostly in women. Population-based epidemiological studies are considered a prerequisite in the surveillance of national and international contact allergy epidemics.

Numerous studies have investigated the prevalence and risk factors of hand eczema in the general population. These studies are of high value as they tend to be less biased than studies using clinical populations and as they are important for healthcare decision makers when they allocate resources. This study aimed to review the epidemiology of hand eczema in the general population.Literature was examined using Pubmed-Medline, Biosis, Science Citation Index, and dermatology text books. On the basis of studies performed between 1964 and 2007, the point prevalence of hand eczema was around 4%, the 1-year prevalence nearly 10%, whereas the lifetime prevalence reached 15%. Based on seven studies, the median incidence rate of hand eczema was 5.5 cases/1000 person-years (women = 9.6 and men = 4.0). A high incidence rate was associated with female sex, contact allergy, atopic dermatitis, and wet work. Atopic dermatitis was the single most important risk factor for hand eczema. Hand eczema resulted in medical consultations in 70%, sick leave (>7 days) in about 20%, and job change in about 10%. Mean sick time was longer among those with allergic hand eczema than those with atopic and irritant hand eczema. Moderate to severe extension of hand eczema was the strongest risk factor for persistence of hand eczema. Other risk factors included early onset of hand eczema and childhood eczema. The aetiology of hand eczema is multifactorial and includes environmental as well as genetic factors. Future studies should focus on unresolved areas of hand eczema, for example, genetic predisposition.Key words: general population; hand eczema; hand dermatitis, nickel allergy; public health; regulation. © John Wiley & Sons A/S, 2010. Accepted for publication 3 November 2009Like contact allergy (1), hand eczema is one of the most frequent dermatological disorders (2-4). In the past, numerous studies have investigated the prevalence and risk factors of hand eczema in the general population. These studies are of high value as they tend to be less biased than studies using clinical populations and as they are important for health care decision makers when they allocate resources. The present article aims to review the epidemiology of hand eczema in the general population. Hopefully, it may serve as a stepping *The content has not been published previously and is not otherwise submitted for publication. stone for future research but also prove useful for clinicians who on daily basis advise their patients about risk factors and prognosis.