When Arizona and Alex were talking to the young patient's mom about his condition, Arizona said he may possibly get psoriasis or liver failure. The correct term is cirrhosis. Psoriasis is a skin condition.
In the opening scenes, Arizona mistakenly says a child suffering from eminent liver failure is at risk for psoriasis when the script called for the word cirrhosis. Psoriasis is a skin disease. Cirrhosis is the medical term for end stage liver disease.