Psoriasis, known medically as psoriasis, can appear everywhere on the body, with elbows and knees being the most common locations. Psoriasis is a chronic, relapsing inflammatory skin disease that can occur throughout the body, usually with a symmetrical distribution of the rash, and more commonly on the extensor sides of the limbs, such as the elbows and knees; it is also likely to occur in the sacrococcygeal region. Patients may have a rash, erythema, scaling and other symptoms on the surface of the skin. Clinical symptoms are different in different parts of the skin, for example, the rash may appear as dotted papules on the face; when the rash appears on the scalp, the scales are usually thicker, and the range even exceeds the hairline; the lesions on the trunk and limbs may appear as plaques covered with silvery-white scales, and spotting hemorrhage can be seen when scraping. Psoriasis usually grows in the elbow, knee and other locations, if you suffer from psoriasis, it is recommended that patients to the hospital for formal treatment.