Tissue Disease: Psoriasis

Psoriasis is identified with the thickening, reddening, and flaking of skin. It can also occur at the nails, scalp, and joints as well. The afflicted area may be raised up to several millimeters above the skin, is typically one centimeter in diameter, and is called a plaque. The flaking that occurs from psoriasis can range from different types of visibility, and are known as ostraceous scales. The cause of psoriasis is vague for now, as scientists are not sure whether it is based solely on genetics, or if environmental factors have a major role in the disease. Sometimes, signs of psoriasis may lead doctors to investigate whether the surface symptoms reveal to be more invasive diseases, such as rheumatoid or arthritis.



Credit http://www.medicinenet.com/psoriasis/article.htm
http://images.medicinenet.com/images/slideshow/adult_skin_s4.jpg