Clinical Practice Guidelines for the Diagnosis and Treatment of Scabies in Korea: Part 1. Epidemiology, Clinical Manifestations, and Diagnosis

Scabies is a skin disease caused by the parasite Sarcoptes scabiei var. hominis, 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 people/yr in 2010 to approximately 30,000 people/yr in 2021. However, outbreaks have been consistently observed in residential facilities, such as nursing facilities, particularly among the older population. The clinical manifestations of scabies vary depending on a patient's age, health status, number of mites, and transmission route. Typical clinical presentations of classic scabies include intense nocturnal pruritus and characteristic skin rashes (burrows and erythematous papules), with a predilection for the interdigital web spaces, inner wrists, periumbilical areas, axillae, and genital areas. Unlike classic scabies, older adults with immunodeficiency or neurological disorders exhibit hyperkeratotic scaly lesions or an atypical distribution with mild-to-non pruritus (crusted scabies). Diagnosis of scabies is based on clinical symptoms and results of diagnostic tests aimed at identifying the presence of the parasite. Although a close contact history and characteristic clinical findings are suggestive of scabies, confirmation of diagnosis requires detection of 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.