A case of Scabies

A35-year-old woman presents with a pruritic rash that has been present over the last few weeks. The area affected is in the webs of the fingers, and symptoms are reported to be worse at night. Topical over-the-counter steroids have not been beneficial. The likely diagnosis is:

• A)poison ivy
• B)dyshidrotic eczema
• C)scabies
• D)tinea corporis
• E)psoriasis

The answer is ( C ). (Scabies) 
The condition of scabies is associated with intense pruritus that is noted predominantly at night. The lesions are brownish in color and often form irregular burrow lines that may be marked with scaling at one end and a vesicle at the other end. The lesions are typically found in intertriginous areas and warm, protected areas such as the finger webs, inframammary areas, and axilla. The mite Sarcoptes scabei is responsible. Scrapings of the lesion are treated with 10% potassium hydroxide solution and studied under light microscopy. The mite is often identified. Treatment consists of permethrin cream 5% applied from head to toes and left in place for 12 hours before being washed off. Lindane can also be used as an alternative, but not in infants or in pregnant women.