Dermpedia

Sharing dermatology and dermatopathology knowledge

Scabies is a highly contagious dermatogical condition caused by the mite, Sarcoptes scabiei. The female mite burrows into the epidermis to lay eggs. Larvae hatch in 3-5 days, mature about 2 weeks later, and then migrate to the surface and mate to continue the cycle. Papules and burrows are often found in the webbing between the fingers and toes, or the sides of fingers.

The host immunologic response (immune complex mediated)  to the mite or its feces (seen microscopically as scybala when hardened) produces the intense itching experienced by patients. Secondary infection is common. 

Scabies transmitted by prolonged skin to skin contact contact.

Who is affected: those living in poor socioeconomic conditions, overcrowded areas (eg nursing homes, jails), and have poor personal hygiene. Scabies can be transmitted during sexual contact.

Microscopic features: acanthosis, hyperkeratosis, and often spongiosis with lymphocytic infiltrate.  The mite is usually subcorneal, at the junction between the epidermis and stratum corneum.

Diagnosis: is made by visualizing the mite, mite parts or its feces.

Treatment of choice: topical permethrin cream.

Prevention measures: good personal hygiene; machine wash infected laundry with hot water; seal infected objects (toys) in a plastic bag for 3 days.