Answer the following question: Information:  - Ankylosing spondylitis (AS) is a type of arthritis in which there is long term inflammation of the joints of the spine. Typically the joints where the spine joins the pelvis are also affected. Occasionally other joints such as the shoulders or hips are involved. Eye and bowel problems may also occur. Back pain is a characteristic symptom of AS, and it often comes and goes. Stiffness of the affected joints generally worsens over time. The cause of ankylosing spondylitis is unknown; however, it is believed to involve a combination of genetic and environmental factors. More than 90% of those effected have a specific human leukocyte antigen known as the HLA-B27 antigen. The underlying mechanism is believed to be autoimmune or autoinflammatory. Diagnosis is typically based on the symptoms with support from medical imaging and blood tests. AS is a type of seronegative spondyloarthropathy, meaning that tests show no presence of rheumatoid factor (RF) antibodies. There is no cure for ankylosing spondylitis. Treatments may improve symptoms and prevent worsening. This may include medication, exercise, and surgery. Medications used include NSAIDs, steroids, DMARDs such as sulfasalazine, and biologic agents such as infliximab. Between 0.1% and 1.8% of people are affected. Onset is typically in young adults. Males are more often affected than females. The condition was first fully described in the late 1600s by Bernard Connor; however, skeletons with ankylosing spondylitis are found in Egyptian mummies. The word is from Greek "ankylos" meaning stiffening, "spondylos" meaning vertebra, and "-itis" meaning inflammation.  - Guttate psoriasis (also known as eruptive psoriasis) is a type of psoriasis that presents as small (0.51.5 cm in diameter) lesions over the upper trunk and proximal extremities; it is found frequently in young adults. Guttate psoriasis is classically triggered by a bacterial infection, usually an upper respiratory tract infection.  - Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In some types other organs are also affected. Onset can be gradual or sudden. There are over 100 types of arthritis. The most common forms are osteoarthritis (degenerative joint disease) and rheumatoid arthritis. Osteoarthritis usually occurs with age and affects the fingers, knees, and hips. Rheumatoid arthritis is an autoimmune disorder that often affects the hands and feet. Other types include gout, lupus, fibromyalgia, and septic arthritis. They are all types of rheumatic disease. Treatment may include resting the joint and alternating between applying ice and heat. Weight loss and exercise may also be useful. Pain medications such as ibuprofen and paracetamol (acetaminophen) may be used. In some a joint replacement may be useful. Osteoarthritis affects more than 3.8% of people while rheumatoid arthritis affects about 0.24% of people. Gout affects about 1 to 2% of the Western population at some point in their lives. In Australia about 15% of people are affected, while in the United States more than 20% of have a type of arthritis. Overall the disease becomes more common with age. Arthritis is a common reason that people miss work and can result in a decreased quality of life. The term is from Greek "arthro-" meaning joint and "-itis" meaning inflammation.  - Lymphoma is a group of blood cell tumors that develop from lymphocytes (a type of white blood cell). The name often refers to just the cancerous ones rather than all such tumors. Signs and symptoms may include enlarged lymph nodes, fever, drenching sweats, unintended weight loss, itching, and constantly feeling tired. The enlarged lymph nodes are usually painless. The sweats are most common at night. There are dozens of subtypes of lymphomas. The two main categories of lymphomas are Hodgkin's lymphomas (HL) and the non-Hodgkin lymphomas (NHL). The World Health Organization (WHO) includes two other categories as types of lymphoma: multiple myeloma and immunoproliferative diseases. About 90% of lymphomas are non-Hodgkin lymphomas. Lymphomas and leukemias are a part of the broader group of tumors of the hematopoietic and lymphoid tissues. Risk factors for Hodgkin lymphoma include infection with EpsteinBarr virus and a history of the disease in the family. Risk factors for common types of non-Hodgkin lymphomas include autoimmune diseases, HIV/AIDS, infection with human T-lymphotropic virus, immunosuppressant medications, and some pesticides. Eating large amounts of red meat and tobacco smoking may also increase the risk. Diagnosis, if enlarged lymph nodes are present, is usually by lymph node biopsy. Blood, urine, and bone marrow testing may also be useful in the diagnosis. Medical imaging may then be done to determine if and where the cancer has spread. Lymphoma most often spreads to the lungs, liver, and/or brain. Treatment may involve one or more of the following: chemotherapy, radiation therapy, targeted therapy, and surgery. In some non-Hodgkin lymphomas, an increased amount of protein produced by the lymphoma cells causes the blood to become so thick that plasmapheresis is performed to remove the protein. Watchful waiting may be appropriate for certain types. The outcome depends on the subtype with some being curable and treatment prolonging survival in most. The five-year survival rate in the United States...  - A blister is a small pocket of lymph within the upper layers of the skin, typically caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid, either serum or plasma. However, blisters can be filled with blood (known as blood blisters) or with pus (if they become infected).  - Replacement arthroplasty (from Greek "arthron", joint, limb, articulate, + "plassein", to form, mould, forge, feign, make an image of), or joint replacement surgery, is a procedure of orthopedic surgery in which an arthritic or dysfunctional joint surface is replaced with an orthopedic prosthesis. Joint replacement is considered as a treatment when severe joint pain or dysfunction is not alleviated by less-invasive therapies. During the latter half of the 20th century, rheumasurgery developed as a subspecialty focused on these and a few other procedures in patients with rheumatic diseases.  - Human leukocyte antigen (HLA) B27 (subtypes B*2701-2759) is a class I surface antigen encoded by the B locus in the major histocompatibility complex (MHC) on chromosome 6 and presents antigenic peptides (derived from self and non-self antigens) to T cells. HLA-B27 is strongly associated with ankylosing spondylitis (AS), and other associated inflammatory diseases referred to as "spondyloarthropathies". Diseases associated with the HLA-B27 subtype can be remembered with the mnemonic PAIR, and include Psoriasis, Ankylosing spondylitis, Inflammatory bowel disease, and Reactive arthritis.  - Fibromyalgia (FM) is a medical condition characterised by chronic widespread pain and a heightened pain response to pressure. Other symptoms include feeling tired to a degree that normal activities are affected, sleep problems, and troubles with memory. Some people also report restless legs syndrome, bowel or bladder problems, numbness and tingling, and sensitivity to noise, lights or temperature. Fibromyalgia is frequently associated with depression, anxiety, and posttraumatic stress disorder. Other types of chronic pain are also frequently present. The cause of fibromyalgia is unknown; however, it is believed to involve a combination of genetic and environmental factors with half the risk attributed to each. The condition runs in families and many genes are believed to be involved. Environmental factors may include psychological stress, trauma, and certain infections. The pain appears to result from processes in the central nervous system and the condition is referred to as a "central sensitization syndrome". Fibromyalgia is recognized as a disorder by the US National Institutes of Health and the American College of Rheumatology. There is no specific diagnostic test. Diagnosis involves first ruling out other potential causes and verifying that a set number of symptoms are present. The treatment of fibromyalgia can be difficult. Recommendations often include getting enough sleep, exercising regularly, and eating a healthy diet. Cognitive behavioral therapy may also be helpful. The medications duloxetine, milnacipran, or pregabalin may be used. Use of opioid pain medication is controversial with some stating their use is poorly supported by evidence and others saying that weak opioids may be reasonable if other medications are not effective. Dietary supplements also lack evidence to support their use. While fibromyalgia can last a long time, it does not result in death or tissue damage. Fibromyalgia is estimated to affect 28% of the population. Females are affected about twice as often as males. Rates appear...  - A disease is a particular abnormal condition, a disorder of a structure or function, that affects part or all of an organism. The study of disease is called pathology which includes the causal study of etiology. Disease is often construed as a medical condition associated with specific symptoms and signs. It may be caused by external factors such as pathogens, or it may be caused by internal dysfunctions particularly of the immune system such as an immunodeficiency, or a hypersensitivity including allergies and autoimmunity.  - Psoriasis is a long-lasting autoimmune disease which is characterized by patches of abnormal skin. These skin patches are typically red, itchy, and scaly. They may vary in severity from small and localized to complete body coverage. Injury to the skin can trigger psoriatic skin changes at that spot, which is known as the Koebner phenomenon. There are five main types of psoriasis: plaque, guttate, inverse, pustular, and erythrodermic. Plaque psoriasis, also known as psoriasis vulgaris, makes up about 90% of cases. It typically presents with red patches with white scales on top. Areas of the body most commonly affected are the back of the forearms, shins, around the navel, and the scalp. Guttate psoriasis has drop-shaped lesions. Pustular psoriasis presents with small non-infectious pus-filled blisters. Inverse psoriasis forms red patches in skin folds. Erythrodermic psoriasis occurs when the rash becomes very widespread, and can develop from any of the other types. Fingernails and toenails are affected in most people at some point in time. This may include pits in the nails or changes in nail color. Psoriasis is generally thought to be a genetic disease which is triggered by environmental factors. In twin studies, identical twins are three times more likely to both be affected compared to non-identical twins; this suggests that genetic factors predispose to psoriasis. Symptoms often worsen during winter and with certain medications such as beta blockers or NSAIDs. Infections and psychological stress may also play a role. Psoriasis is not contagious. The underlying mechanism involves the immune system reacting to skin cells. Diagnosis is typically based on the signs and symptoms. There is no cure for psoriasis. However, various treatments can help control the symptoms. These treatments may include steroid creams, vitamin D3 cream, ultraviolet light, and immune system suppressing medications such as methotrexate. About 75% of cases can be managed with creams alone. The disease affects 24% of the population. Men...  - Septic arthritis, also known as infectious arthritis or joint infection, is the purulent invasion of a joint by an infectious agent which produces arthritis. People with artificial joints are more at risk than the general population but have slightly different symptoms, are infected with different organisms and require different treatment. Septic arthritis is considered a medical emergency. If untreated, it may destroy the joint in a period of days. The infection may also spread to other parts of the body.  - Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any part of the gastrointestinal tract from mouth to anus. Signs and symptoms often include abdominal pain, diarrhea (which may be bloody if inflammation is severe), fever, and weight loss. Other complications may occur outside the gastrointestinal tract and include anemia, skin rashes, arthritis, inflammation of the eye, and feeling tired. The skin rashes may be due to infections as well as pyoderma gangrenosum or erythema nodosum. Bowel obstruction also commonly occurs and those with the disease are at greater risk of bowel cancer. Crohn's disease is caused by a combination of environmental, immune and bacterial factors in genetically susceptible individuals. It results in a chronic inflammatory disorder, in which the body's immune system attacks the gastrointestinal tract possibly directed at microbial antigens. While Crohn's is an immune related disease, it does not appear to be an autoimmune disease (in that the immune system is not being triggered by the body itself). The exact underlying immune problem is not clear; however, it may be an immunodeficiency state. About half of the overall risk is related to genetics with more than 70 genes found to be involved. Tobacco smokers are two times more likely to develop Crohn's disease than nonsmokers. It also often begins after gastroenteritis. Diagnosis is based on a number of findings including biopsy and appearance of the bowel wall, medical imaging and description of the disease. Other conditions that can present similarly include irritable bowel syndrome and Behçet's disease. There are no medications or surgical procedures that can cure Crohn's disease. Treatment options help with symptoms, maintain remission, and prevent relapse. In those newly diagnosed, a corticosteroid may be used for a brief period of time to quickly improve the disease with another medication such as either methotrexate or a thiopurine used to prevent recurrence. An important part of treatment is the...  - Psoriatic arthritis ( also arthritis psoriatica , arthropathic psoriasis or psoriatic arthropathy ) is a type of inflammatory arthritis that will develop in up to 30 percent of people who have the chronic skin condition psoriasis . Psoriatic arthritis is classified as a seronegative spondyloarthropathy and therefore occurs more commonly in patients with tissue type HLA - B27 .  - Pus is an exudate, typically white-yellow, yellow, or yellow-brown, formed at the site of inflammation during bacterial or fungal infection. An accumulation of pus in an enclosed tissue space is known as an abscess, whereas a visible collection of pus within or beneath the epidermis is known as a pustule, pimple, or "spot".  - Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involved, with the same joints typically involved on both sides of the body. The disease may also affect other parts of the body. This may result in a low red blood cell count, inflammation around the lungs, and inflammation around the heart. Fever and low energy may also be present. Often, symptoms come on gradually over weeks to months. While the cause of rheumatoid arthritis is not clear, it is believed to involve a combination of genetic and environmental factors. The underlying mechanism involves the body's immune system attacking the joints. This results in inflammation and thickening of the joint capsule. It also affects the underlying bone and cartilage. The diagnosis is made mostly on the basis of a person's signs and symptoms. X-rays and laboratory testing may support a diagnosis or exclude other diseases with similar symptoms. Other diseases that may present similarly include systemic lupus erythematosus, psoriatic arthritis, and fibromyalgia among others. The goal of treatment is to reduce pain, decrease inflammation, and improve a person's overall functioning. This may be helped by balancing rest and exercise, the use of splints and braces, or the use of assistive devices. Pain medications, steroids, and NSAIDs are frequently used to help with symptoms. A group of medications called disease-modifying antirheumatic drugs (DMARDs), such as hydroxychloroquine and methotrexate, may be used to try to slow the progression of disease. Biological DMARDs may be used when disease does not respond to other treatments. However, they may have a greater rate of adverse effects. Surgery to repair, replace, or fuse joints may help in certain situations. Most alternative medicine treatments are not supported by evidence. RA affects between 0.5 and 1% of adults in the developed...  - Osteoarthritis (OA) is a type of joint disease that results from breakdown of joint cartilage and underlying bone. The most common symptoms are joint pain and stiffness. Initially, symptoms may occur only following exercise, but over time may become constant. Other symptoms may include joint swelling, decreased range of motion, and when the back is affected weakness or numbness of the arms and legs. The most commonly involved joints are those near the ends of the fingers, at the base of the thumb, neck, lower back, knee, and hips. Joints on one side of the body are often more affected than those on the other. Usually the symptoms come on over years. It can affect work and normal daily activities. Unlike other types of arthritis, only the joints are typically affected. Causes include previous joint injury, abnormal joint or limb development, and inherited factors. Risk is greater in those who are overweight, have one leg of a different length, and have jobs that result in high levels of joint stress. Osteoarthritis is believed to be caused by mechanical stress on the joint and low grade inflammatory processes. It develops as cartilage is lost and the underlying bone becomes affected. As pain may make it difficult to exercise, muscle loss may occur. Diagnosis is typically based on signs and symptoms, with medical imaging and other tests occasionally used to either support or rule out other problems. In contrast to rheumatoid arthritis, which is primarily an inflammatory condition, in osteoarthritis, the joints do not typically become hot or red. Treatment includes exercise, efforts to decrease joint stress, support groups, and pain medications. Efforts to decrease joint stress include resting and the use of a cane. Weight loss may help in those who are overweight. Pain medications may include paracetamol (acetaminophen) as well as NSAIDs such as naproxen or ibuprofen. Long-term opioid use is generally discouraged due to lack of information on benefits as well as risks of addiction and other side effects. If...    After reading the paragraphs above, we are interested in knowing the entity with which 'psoriatic arthritis' exhibits the relationship of 'medical specialty'. Find the answer from the choices below.  Choices: - genetics  - infection  - pathology  - rheumatology  - surgery
Answer:
rheumatology