In addition, the disease can also affect fingernails, toenails, mucous membranes, and sometimes even joints, bones, tendons, ligaments, etc. However, the tell-tale symptoms of most types of psoriasis Psoriasis is inflamed and scaly skin, most commonly in the form of small red or dark patches of skin, covered with white or gray scales, appearing near the elbows, back, neck, scalp,... This scab easily flakes off when scratched and looks like the scales that come out from candle wax (hence the name psoriasis).