Psoriasis can be mild, with rash on small areas. In moderate or severe psoriasis, the skin gets inflamed with raised red areas topped with loose, silvery, scales. In case of severe psoriasis, the skin becomes itchy and tender and sometimes large patches form and may be uncomfortable. Sometimes, the patches can join together and cover large areas of skin, such as the entire back.

Psoriasis can also affect the fingernails and toenails, causing the nails to pit, change color, resulting in separation from the nail bed.