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.