Which insect bite causes intense pruritus with burrows concentrated on web spaces, fingers, and toes?

• A. Bed bug bites
• B. Lice bites
• C. Scabies
• D. Flea bites

Answer: (C)

Burrows in the web spaces between the fingers and toes with intense itching is classic for scabies. The itching, often worst at night, comes from a hypersensitivity reaction to the mites, eggs, and feces that live in the superficial skin. The burrows themselves are thin, serpiginous tracks in the stratum corneum and are most evident in interdigital areas, wrists, and other flexural sites. This combination—severe nocturnal itching plus characteristic burrows in the web spaces—distinguishes scabies from other insect bites: bed bug bites tend to affect exposed skin and lack burrows; lice bites are associated with hair-bearing regions and nits; flea bites commonly cluster on the legs. Therefore, scabies is the most likely diagnosis. Treatment involves topical scabicides (like permethrin 5%) or oral ivermectin for the patient and close contacts, along with thorough cleaning of clothing, bedding, and environment.