A 70-year-old immunocompromised patient in a nursing home presents with generalized thick crusted lesions over the scalp, face, and hands. Microscopy of scrapings shows hundreds of Sarcoptes scabiei mites and eggs. The treatment of choice and the precautionary measure required are:

• A Permethrin 5% cream x1 application; no special precautions
• B Benzyl benzoate 25% daily for 3 days; quarantine for 48 hours
• C Topical malathion 0.5% lotion x2 applications 1 week apart
• D Oral ivermectin 200 μg/kg on day 1, 2, 8, 9, 15 (and 22, 29 for severe cases); strict contact isolation ✓

Explanation

Norwegian (crusted) scabies occurs in immunocompromised patients and is characterized by hyperkeratotic crusts harboring thousands to millions of mites, making it highly contagious. Single-dose permethrin or ivermectin is insufficient for crusted scabies. WHO and international guidelines recommend oral ivermectin 200 μg/kg on days 1, 2, 8, 9, 15 with repeat dosing on days 22 and 29 for severe cases, combined with topical keratolytics (salicylic acid) to remove crusts and topical scabicide (permethrin 5%). Strict contact isolation and treatment of all contacts and healthcare workers is mandatory to prevent institutional outbreaks. Benzyl benzoate is an alternative topical for ordinary scabies.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.