Figure 1 Quiz of the Week
A 38-year-old man presents with itchy, scaly lesions on his elbows and small, erythematous papules in the web spaces of his fingers.

Image credit:Ìý.
Answer: Scabies
Scabies is caused by the tick Sarcoptes scabiei, that burrows into human skin where it lays its eggs. The inflammation is caused by a type IV hypersensitivity reaction which produces erythema and intense pruritus that is often worse at night. Scabies can be treated with topical or systemic therapy.
!
Explore cases, quiz yourself, and solve medical mysteries along with thousands of other medical professionals around the world onÌý, the free app where doctors expand their clinical knowledge.