Psoriatic arthritis, a chronic disease, is characterized by inflammation or swelling of skin (psoriasis) and joints (arthritis). It features patchy, red areas of human skin with inflammation and scaling. Psoriasis frequently affects the tips of our elbows and knees, the scalp, around the genital areas and the navel. Approximately 30% of patients who get psoriasis also develop an inflammation of joints. And patients having inflammatory arthritis and psoriasis are mostly diagnosed for having psoriatic arthritis.

The beginning of psoriatic arthritis is generally found in the fourth and fifth decade of human life. Gents and ladies are equally affected. The skin disease and the arthritis often appear separate. In fact, the psoriasis precedes the joint disease in about 80% of patients. But sometimes the arthritis also precedes the psoriasis in 15% of patients. In some people, the diagnosis of this arthritis may become difficult if the joint disease precedes psoriasis by long years. In fact, some patients have arthritis for more than 20 years before psoriasis actually appears! But also, patients have psoriasis for more than 20 years prior to arthritis development, leading to the diagnosis of psoriatic arthritis. This type of arthritis is nothing but a systemic rheumatic disease that can cause inflammation in body tissues other than the skin, such as in eyes, lungs, heart, and kidneys. It shares several other arthritic conditions, like ankylosing spondylitis, reactive arthritis (formerly known as Reiter's syndrome), and also arthritis associated along with Crohn's disease and ulcerative colitis. All these conditions may cause inflammation or swelling in the spine and other joints also, and the eyes, mouth, skin, and various other organs. According to their similarities and tendency to give rise to inflammation of spine, these conditions are conjointly called as "spondyloarthropathies."

Genetic problems, disorder in immune system as well as atmospheric changes are the most important causes of this disease. In patients with the above cited disease who have arthritis of spine, a gene named HLA-B27 is frequently found. Blood testing is now available to test this. Several others are also found to be more common in patients with this arthritis. Some changes in immune system may be important sometimes in its development. For example, the decline in the number of helper T cells in AIDS patients plays a role in the development and progression of the disease psoriasis in patients. Now-a-days the importance of these infectious agents and also other environmental factors in the cause of this arthritis is investigated by researchers.

Pustular psoriasis is also one of the several types of psoriasis which causes parts of our skin to redden, expand and covered by pus-filled blisters called as pustules. There are also several subtypes of this psoriasis. It may stay confined to small areas of patients' body; some times, just on the palms of our hands, the soles of our feet, or the fingers and toes are harmed and this is called the focal form of this disease. But It also can cover larger areas of the body as well. The generalized form which is also called as von Zumbusch psoriasis is more serious, and this form can also be fatal. For its cure we have to follow the same steps as in normal psoriasis like, reducing stress, smoking, drinking and dealing a healthy life. Its treatment also follows the three processes that are, topical, light therapy and systemic.