 It may involve, for example, using deodorants or perfume, shaving, or combing, besides other practices.Excessive body hygiene is one example of obsessive compulsive disorder.The hygiene hypothesis was first formulated in 1989 by Strachan who observed that there was an inverse relationship between family size and development of atopic allergic disorders—the more children in a family, the less likely they were to develop these allergies.