Final answer:
To diagnose psoriasis with an abrupt onset and widespread involvement, a skin biopsy and blood tests to check for specific markers associated with psoriasis can be ordered.
Step-by-step explanation:
Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. It commonly affects areas such as the elbows, knees, scalp, back, face, palms, and feet. If a person has psoriasis with an abrupt onset and widespread involvement, there are certain tests that can be ordered to help diagnose the condition. One of the common tests for psoriasis is a skin biopsy. This involves removing a small piece of skin and examining it under a microscope to look for the characteristic features of psoriasis, such as thickened skin and abnormal cell growth. In addition, blood tests may be ordered to check for specific markers that are associated with psoriasis. These markers include elevated levels of certain immune cells, such as T cells and dendritic cells, as well as increased levels of inflammatory cytokines. These blood tests can help confirm the diagnosis of psoriasis and provide information about the severity and potential complications of the condition.