section_path: Personal hygiene/Challenges/Hygiene hypothesis and allergies
section_name: Hygiene hypothesis and allergies
paragraph_text: Hygiene hypothesis and allergies
  
  Although media coverage of the hygiene hypothesis has declined, popular folklore continues to sometimes assert that dirt is healthy and hygiene unnatural. This has caused health professionals to be concerned that hygiene behaviors which are the foundation of public health are being undermined. In response to the need for effective hygiene in home and everyday life settings, the International Scientific Forum on Home Hygiene developed a "risk-based" or targeted approach to home hygiene that seeks to ensure that hygiene measures are focused on the places and times most critical for infection transmission. While targeted hygiene was originally developed as an effective approach to hygiene practice, it also seeks, as far as possible, to sustain "normal" levels of exposure to the microbial flora of our environment to the extent that is important to build a balanced immune system.
  
  Although there is substantial evidence that some microbial exposures in early childhood can in some way protect against allergies, there is no evidence that humans need exposure to harmful microbes (infection) or that it is necessary to develop a clinical infection. Nor is there evidence that hygiene measures such as hand washing, food hygiene, etc., are linked to increased susceptibility to atopic disease. If this is the case, there is no conflict between the goals of preventing infection and minimizing allergies. A consensus is now developing among experts that the answer lies in more fundamental changes in lifestyles that have led to decreased exposure to certain microbial or other species, such as helminths, that are important for development of immuno-regulatory mechanisms. There is still much uncertainty as to which lifestyle factors are involved.