Step 1 : Introduction to the question " What is psoriasis? "
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Psoriasis is a chronic, long-lasting, disease in which the immune system becomes overactive, causing skin cells to multiply too quickly. Patches of skin become scaly and inflamed, most often on the scalp, elbows, or knees, but other parts of the body can be affected as well. Scientists do not fully understand what causes psoriasis, but they know that it involves a mix of genetics and environmental factors. It is generally thought to be a genetic disease that is triggered by environmental factors
It's a common condition affecting about 8 million people in the US and 125 million worldwide. The five main types of psoriasis are plaque, guttate, inverse, pustular, and erythrodermic. Plaque psoriasis, also known as psoriasis vulgaris, makes up about 90% of cases. It typically presents as red patches with white scales on top. Areas of the body most commonly affected are the back of the forearms, shins, navel area, and scalp. Guttate psoriasis has drop-shaped lesions. Pustular psoriasis presents as small, noninfectious, pus-filled blisters. Inverse psoriasis forms red patches in skin folds. Erythrodermic psoriasis occurs when the rash becomes very widespread, and can develop from any of the other types.
Treatment with creams and medications can help but it can't be cured.
More Info:
en.wikipedia.org