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Why does skin become abnormally thick in psoriasis?

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Learn how regenerative properties of the skin helps to protect the human body from the external environment — human skin Human skin, whose cells are generated continuously by the body, serves as a protective barrier between the inside of the human body and the environment.

In psoriasis, the skin becomes abnormally thick due to an accelerated rate of keratinocyte proliferation.12

Under normal conditions, the production and loss of skin cells are finely balanced, with a typical cell life span of 20 to 28 days. In psoriatic skin, however, the immune system—specifically T cells—mistakenly attacks healthy skin cells. This immune-mediated response triggers a rapid turnover, shortening the life span of skin cells to approximately 3 to 5 days.32

This increased thickness occurs because the rate of cell production in the malpighian layer is significantly higher than normal, and cells move through the epidermis much faster. Researchers believe this is likely achieved by recruiting resting cells into the mitotic cycle and speeding up the cell cycle itself. The resulting accumulation of these rapidly produced cells manifests as the characteristic raised, scaly plaques associated with the disorder.213