Harold is a 50-year-old, overweight, diabetic, hardworking father of three. He has a 15-year smoking addiction. He isn’t crazy about his job and has a habit of scratching his head while sitting at his desk. For the past several months he has noticed dandruff-like flakes falling onto his paperwork. He assumed this was due to dandruff and has been using a dandruff shampoo, with no improvement. Harold has also noticed that his fingernails are pitted and discolored. Today he is itching around his belt line. This is nearly as distracting as the itchy, scaly patches on his anterior knees and the posterior surfaces of his elbows. These round patches are raised, reddened, and scaly with silvery plaques. They are tender and have been enlarging and worsening for the past few weeks. Harold is so concerned about these skin lesions that he consults a dermatologist (skin doctor), who performs a skin biopsy. The dermatologist comments that, under the microscope, the tissue looks like epidermis in "overdrive."Every day your epidermis normally sheds dead skin cells. What is the first step in the process by which epidermal cells are replaced?

It takes about 28 days for young skin cells to reach the surface, however in mature skin they need more time. And that's why more dead cells accumulate in the skin, because the process is slower. When the cells are formed, they will begin to move towards the surface of your epidermis. This usually lasts about from two weeks to a month. The more mature cells die and reach the surface of your skin, detach from your body in the form of scales.