Epidemiology

The knowledge about the epidemiology of LCH is a very undevelopped field. Information concerning two major aspects of the disorder are coming from epidemiology:

• The frequency of patients suffering from the disease in a given population and perhaps some geographic or temporal variations.
• The risk factor for the outset of the disease.

Due to the rarity of the disease, its multisystemic character and by consequence the great number of medical specialists involved in the care, even the simple count of new patients in a certain time is very difficult. Therefore, the incidence rate in children is only partially known and in adults, it can be considered as unknown. The prevalence which takes into account new patients, patients with reactivations, and patients with permanent consequences has never been scientifically evaluated, even some deduction can be done.
The risk factors have been analyzed once.