Every year in France, scabies outbreaks affect several hundred facilities housing the elderly, due to the extreme contagiousness of this parasitic infection and the high susceptibility of residents to scabies. Given the multiple causes of pruritus in the elderly, two requirements are essential for the rapid and effective control of a scabies outbreak in a facility: early diagnosis and its confirmation. In January 2000, CIRE Ouest was alerted by the Morbihan Departmental Directorate for Social Affairs (DDASS) to a resurgence of scabies, within a context described as endemic-epidemic since March 1997. An investigation was launched to confirm the existence of the problem, describe its characteristics, identify factors promoting its transmission, and adjust recommendations. A retrospective descriptive study was conducted from March 1997 to December 1999. The study population included the facility’s 120 residents, 100 staff members (regular and temporary), visitors, and family members. The only identified source of information was a logbook maintained by the nursing staff containing details on the identity of the affected person, the room, the date of identification, the date of treatment, and any observations. In order to describe the cases in terms of time, place, and individuals, a case definition was established retrospectively in three categories: an episode of pruritus attributed to scabies based on a positive parasitological examination was defined as a biologically confirmed case; an episode of pruritus attributed to scabies following a medical consultation was defined as a clinically confirmed case; an episode of pruritus without an etiological diagnosis and not attributed to scabies by a physician was defined as a possible case. It should be noted that, given these definitions, an individual could have been counted multiple times as a case during the study period. An on-site visit was also conducted. Over 34 months, between March 1997 and December 1999, a total of 106 possible and confirmed cases of scabies were identified, 98 (92%) among residents and 8 (8%) among non-residents (5 cases among staff and 3 cases among family members). The 98 cases identified among residents involved 57 individuals, representing a reinfestation rate of 40% (n=23); no cases were biologically confirmed, 19% (n=19, including 1 case of Norwegian scabies) were clinically confirmed, and 81% (n=79) were possible cases. The 8 cases identified among non-residents (staff and family members) involved 7 people: no biologically confirmed cases, 75% (n=6) clinically confirmed, and 25% (n=2) possible cases. The epidemic curve suggests an endemic-epidemic situation with an average prevalence of scabies around 12%. All housing sectors were affected, with the most affected being those containing communal areas (meals, recreational spaces, etc.). The movement of residents within the housing sectors over the study period could not be reconstructed. The retrospective investigation encountered two major difficulties: first, the existence of a single data source, which did not allow for the validation of the information in terms of either reliability or completeness; second, the failure to identify the parasite after 34 months, which could call into question the very existence of the problem. The main merit of implementing rational investigative methods is that it highlighted the importance of confirming the diagnosis of scabies and conducting epidemiological surveillance. Indeed, it made it possible to identify 106 cases of scabies over 34 months, but this figure must be qualified due to the lack of diagnostic evidence; furthermore, the available data did not allow for a supplementary epidemiological investigation aimed at identifying risk factors. However, the risk factors for scabies are well known, particularly poor hygiene conditions, several of which had already been identified by the facility. This type of facility also faces the problem of insufficient cooperation between consulting private practitioners and public health professionals. Recommendations have been proposed. No new cases of scabies have been identified since February 2000.