Clinical practice guidelines for the diagnosis and treatment of scabies in Korea: Part 1. Epidemiology, clinical manifestations, and diagnosis - a secondary publication.

Scabies is a skin disease caused by the parasite Sarcoptes scabiei var. hominis, which is primarily transmitted via direct skin or sexual contact or, less commonly, via contact with infested fomites. In Korea, the incidence of scabies has decreased from approximately 50,000 cases per year in 2010 to about 30,000 cases per year in 2021. However, outbreaks are consistently observed in residential facilities, such as nursing homes, especially among older adults. The clinical manifestations of scabies vary based on the patient's age, health status, the number of mites, and the route of transmission. Typical symptoms of classic scabies include intense nocturnal itching and characteristic skin rashes (burrows and erythematous papules), with a predilection for the interdigital web spaces, inner wrists, periumbilical areas, axillae, and genital areas. In contrast, older adults with immunodeficiency or neurological disorders may exhibit hyperkeratotic scaly lesions or an atypical distribution with mild to no itching (crusted scabies). The diagnosis of scabies is based on clinical symptoms and the results of diagnostic tests aimed at identifying the presence of the parasite. While a history of close contact and characteristic clinical findings suggest scabies, confirmation of the diagnosis requires detecting scabies mites, eggs, or scybala. This can be achieved through light microscopy of skin samples, non-invasive dermoscopy, and other high-resolution in vivo imaging techniques.