Final answer:
A nurse should refer a client to a dermatologist immediately if skin lesions show signs that may indicate skin cancer such as asymmetry, irregular borders, varied color, and large diameter, or if there is a rapidly progressing severe infection like necrotizing fasciitis.
Step-by-step explanation:
When a nurse is conducting skin assessments on clients, there are specific lesions that would prompt an immediate referral to a dermatologist. Lesions that are asymmetric, have irregular borders, present in varied shades of brown or black, or have a large diameter are concerning signs that may indicate skin cancer, such as melanoma. These characteristics can be remembered with the mnemonic ABCDE, which stands for Asymmetry, Borders, Color, Diameter, and Evolving. It's crucial for early detection and treatment, as skin cancer is most treatable when caught early. A nurse would also refer a client immediately if an infection seems to be rapidly progressing and severe, like in the case of necrotizing fasciitis, which is a life-threatening condition.