How Scabies is Transmitted
Scabies is primarily transmitted through direct, prolonged skin-to-skin contact with an infected person, with indirect transmission through contaminated fomites (bedding, clothing, towels) being less common but possible. 1, 2
Primary Transmission Route
Direct skin-to-skin contact is the main mode of transmission, requiring prolonged contact for the mite (Sarcoptes scabiei var. hominis) to transfer from one person to another. 3, 4, 5
The contact must be sustained and intimate—brief handshakes or casual contact are typically insufficient for transmission in classic scabies. 6
Secondary Transmission Route
Indirect transmission can occur through contaminated fomites including bed linens, clothing, and towels, though this is less common than direct contact. 3, 4
Scabies mites can survive on clothing for up to 4 days without skin contact, but only 1-2 days at room temperature (21°C), making fomite transmission time-limited. 2
Environmental decontamination requires machine washing and drying items using hot cycles, dry cleaning, or removing items from body contact for at least 72 hours. 1, 2
Special Consideration: Crusted (Norwegian) Scabies
Crusted scabies is far more contagious than typical scabies because the skin harbors thousands to millions of mites (versus 10-15 mites in classic scabies). 1
In crusted scabies, mites are dispersed within shed scales, enabling transmission from contaminated surfaces and making this variant highly infectious. 7, 4
This aggressive form occurs in immunodeficient, debilitated, or malnourished persons and poses significant outbreak risk in institutional settings. 1
High-Risk Settings and Populations
Close contacts, overcrowding within households, communities, nursing homes, and healthcare institutions are major risk factors for scabies transmission. 5, 6
Healthcare workers and institutional staff are at occupational risk, particularly in residential homes for the elderly where outbreaks commonly occur. 3
Children under age 2 and elderly individuals are at greatest risk for acquisition and complications. 6
Critical Management Principle
All persons with close personal, sexual, or household contact within the preceding month must be examined and treated simultaneously, even if asymptomatic, as failure to treat contacts is the most common cause of treatment failure. 1, 2
In outbreak settings, all patients, contact persons, and staff must be treated simultaneously to achieve control. 3