7th August 2020

An 88-year-old gentleman presents with a few days history of bilateral itchy rashes on his fingers, wrists and elbows

An 88-year-old gentleman presents with a few days history of bilateral itchy rashes on his fingers, wrists and elbows. The lesions are described as linear burrows associated with some rubbery nodules. His wife, son and daughter, complain that they are all having similar issues, but different areas of their skin are affected. The patient denies any travel history and has always been fit and well. The dermatologist suspects that the patient, as well as all his household members, have contracted the same disease. 

Which THREE of the following investigations can confirm the diagnosis? Select THREE options only.