Eczema epidemiology

Several epidemiology studies on occupational exposure to 1,4-dioxane are available in the literature. Very limited conclusions can be drawn from the negative findings of these studies. All of the studies lack sufficient cohort size and number of cases to enable identification of low-level excess cancer risk. Of note, the reported cancers have various sites of origin and are not similar to those seen in animal models. A mortality study was conducted on employees exposed to 1,4-dioxane. Observed deaths from overall cancer were not significantly different from expected number of deaths. 1,4-Dioxane can be inhaled in amounts sufficient to cause serious systemic intoxication. Injury may become apparent hours after termination of an exposure that had been erroneously considered to be negligible. Prolonged and repeated contact can cause eczema and repeated inhalation exposures to low concentrations have been fatal. 

However, Pearce et al. [14(NC)] have written that the problem of information bias is of particular concern in asthma epidemiology issues because of the difficulties in defining and measuring asthma, allergic rhinoconjunctivitis and atopic eczema, and the difficulties in obtaining exposure information in the aetiologically relevant time period. However, provided that the information has been collected in a standardized manner, then misclassification will be non-differential, and any bias it produces will usually be towards the null value. 

Fisher et al. (1971) introduced the vehicle tray in patch testing and thereby increased the physician s awareness of the possibility of contact allergy to vehicle ingredients. The vast majority of vehicles has not been studied in a systematic fashion they have not been subjected to predictive testing in animals and only limited epidemiologic data exist from screening of eczema patients (Hjorth and Trolle Lassen 1963 Hannuksela et al. 1976 a Iden and Schroeter 1977). 

Even if in epidemiological terms atopic eczema is an effect modifier, it can be argued that the observed ICD associated with atopy is in fact an exacerbation of atopic eczema, rather then ICD. 

Coenraads PJ, Smit J (1995) Epidemiology. In Rycroft RJG, Menne T, Frosch PJ (eds) Textbook of contact dermatitis. Springer, Berlin Heidelberg New York, pp 133-150 Coenraads PJ, Nater JP, van der Lende R (1983) Prevalence of eczema and other dermatoses of the hands and arms in the Netherlands. Association with age and occupation. Clin Exp Dermatol 8 495-503... 

Table 1. Traditional and clinical epidemiology. Comparison of frequencies of positive patch-test reactions in the general population and in eczema patients at a dermatological clinic in the same area of greater Copenhagen in 1990 (from Menne and Knudsen 1997)...

Meding B (1990) Epidemiology of hand eczema in an industrial city. Acta Derm Venereol Stockh Suppl 153 2-43 Meding B, Swanbeck G (1989) Epidemiology of different types of hand eczema in an industrial city. Acta Derm Venereol Stockh 69 227-33... 

This chronic foot eczema is especially common in children and has baffled pediatricians for years. Some clinicians regard it as one of the varied manifestations of atopic eczema. The epidemiologic evidence, however, suggests that it is an example of hydration... 

While population-based epidemiological studies on the frequency of ICD are rare, there is agreement that irritant dermatitis is more frequent than ACD, although ACD tends to have more severe consequences for the patient. Coenraads and Smit (1995) reviewed international prevalence studies for eczema due to all causes conducted with general populations in five countries (England, the Netherlands, Norway, Sweden,... 

Meding B (1990) Epidemiology of hand eczema in an industrial city. Acta Derm Venereol Suppl (Stockh) 153 1-43... 

Rystedt I (1985) Hand eczema and long-term prognosis in atopic dermatitis. Acta Derm Venereol Suppl (Stocldi) 117 1-59 Schubert H, Berova N, Czernielewski A, et al. (1987) Epidemiology of nickel allergy. Contact Dermatitis 16 122-128 Shah M, Lewis FM, Gawkrodger DJ (1996) Prognosis of occupational hand dermatitis in metalworkers. Contact Dermatitis 34 27-30... 

Hand eczema and nickel allergy often affect hairdressers early in their careers and often during their apprenticeship (Wahlberg 1975 Lindemayr 1984). This propensity to allergies among hairdressers will affect their careers and their tendency to leave the occupation, and it also affects the results of epidemiological and clinical studies concerning hairdressers. 

Some authors have doubted that the high prevalence of nickel allergy is due to occupational exposure. Current epidemiological studies will hopefully help to settle the question. In an individual case it must, however, be recognised that occupational nickel exposure might be an important factor contributing to or causing the hairdressers hand eczema. 

By adding ferrous sulfate to the cement, it is possible to prevent the development of allergic cement eczema. This was illustrated in an epidemiological intervention study from Denmark (Avnstorp 1992) and in reports from Finland and Sweden (Roto et al. 1996). 

Hovding G (1970) Cement eczema and chromium allergy, an epidemiologic investigation (thesis). University of Bergen, Norway... 

Most data do not separate cement eczema into subgroups of allergic and irritant. Exact prevalences might therefore be difficult to give. Another problem in the interpretation of data concerning prevalences and incidences is due to the fact that most data are obtained from patch-test clinics. This may give inaccurate information due to selection bias. Studies carried out at work sites provide more accurate epidemiological information. 

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