Recently the prevalence of skin eczema has increased substantially in many countries, especially the industrialized countries where between 10% and 20% of the population has it. This increase (two or three times in the last decade) has been too fast to be explained by genetic changes for improvement when diagnose this skin disease or the higher standard of living of the population. It can, however, suggest that environmental factors play a role in the etiology of this new epidemic.
Several factors have been shown to be associated with the development of eczema , and personal factors such as genetic factors, age, as 85% of cases occur before age five, sex (studies have found increased susceptibility of girls) , nutritional status, snuff consumption, lifestyle, but also environmental stimuli such as environmental pollution, smoke snuff , house dust, animal dander, workplace, cooling systems, or inhaled allergens and aeroallergens, ie substances that airborne in a sensitized person, can trigger respiratory allergy symptoms as allergic rhinitis, bronchospasm and asthma bronchial, conjunctival and skin (atopic eczema). The most important are dust mites, animal dander, pollens and molds.