7th August 2020

A 48-year-old male patient presents with a poorly demarcated, dry, vesicular rash on his left wrist

A 48-year-old male patient presents with a poorly demarcated, dry, vesicular rash on his left wrist. He has recently bought a new watch, and he complains the skin underneath it is very itchy. He has hayfever, as do his brother and mother

Given the likely diagnosis what is the next most appropriate investigation? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.