Psoriasis
Psoriasis is a long-lasting autoimmune disease characterized by patches of abnormal skin.[6] These skin patches are typically red, dry, itchy, and scaly.[3] On people with darker skin the patches may be purple in colour.[9] Psoriasis varies in severity from small, localized patches to complete body coverage.[3] Injury to the skin can trigger psoriatic skin changes at that spot, which is known as the Koebner phenomenon.[10]
There are five main types of psoriasis: plaque, guttate, inverse, pustular, and erythrodermic.[6] Plaque psoriasis, also known as psoriasis vulgaris, makes up about 90 percent of cases.[4] It typically presents as red patches with white scales on top.[4] Areas of the body most commonly affected are the back of the forearms, shins, navel area, and scalp.[4] Guttate psoriasis has drop-shaped lesions.[6] Pustular psoriasis presents as small non-infectious pus-filled blisters.[11] Inverse psoriasis forms red patches in skin folds.[6] Erythrodermic psoriasis occurs when the rash becomes very widespread, and can develop from any of the other types.[4]Fingernails and toenails are affected in most people with psoriasis at some point in time.[4] This may include pits in the nails or changes in nail color.[4]
Psoriasis is generally thought to be a genetic disease that is triggered by environmental factors.[3] In twin studies, identical twins are three times more likely to be affected compared to non-identical twins. This suggests that genetic factors predispose to psoriasis.[4] Symptoms often worsen during winter and with certain medications, such as beta blockers or NSAIDs.[4] Infections and psychological stress can also play a role.[3][6]Psoriasis is not contagious.[4] The underlying mechanism involves the immune system reacting to skin cells.[4] Diagnosis is typically based on the signs and symptoms.[4]
There is no cure for psoriasis; however, various treatments can help control the symptoms.[4] These treatments include steroid creams, vitamin D3 cream, ultraviolet light and immune system suppressing medications, such as methotrexate.[6] About 75 percent of cases can be managed with creams alone.[4] The disease affects two to four percent of the population.[8] Men and women are affected with equal frequency.[6] The disease may begin at any age, but typically starts in adulthood.[5] Psoriasis is associated with an increased risk of psoriatic arthritis, lymphomas, cardiovascular disease, Crohn’s disease and depression.[4] Psoriatic arthritis affects up to 30 percent of individuals with psoriasis.[11]
Waco
Waco (/ˈweɪkoʊ/ way-koh) is a city which is the county seat of McLennan County, Texas, United States.[3] It is situated along the Brazos River and I-35, halfway between Dallas and Austin. The city had a 2010 population of 124,805, making it the 22nd-most populous city in the state.[4] The US Census 2015 population estimate is 132,356.[5] The Waco Metropolitan Statistical Area consists of McLennan and Falls Counties, which had a 2010 population of 234,906.[6] Falls County was added to the Waco MSA in 2013. The US Census 2016 population estimate for the Waco MSA is 265,207.[7]
Indigenous peoples occupied areas along the river for thousands of years. In historic times, the area of present-day Waco was occupied by the Wichita Indian tribe known as the “Waco” (Spanish: Hueco or Huaco).
In 1824, Thomas M. Duke was sent to explore the area after the Waco people tried to defend themselves and their lands from settlers. His report to Stephen F. Austin, described the Waco village:
After further violence due to settler incursion, Austin halted an attempt to destroy their village in retaliation. In 1825, he made a treaty with them. The Waco were eventually pushed out of the region, settling north near present-day Fort Worth. In 1872, they were forced onto a reservation in Oklahoma with other Wichita tribes. In 1902, the Waco received allotments of land and became official US citizens. Neil McLennan settled in an area near the South Bosque River in 1838.[8] Jacob De Cordovabought McLennan’s property[9] and hired a former Texas Ranger and surveyor named George B. Erath to inspect the area.[10]In 1849, Erath designed the first block of the city. Property owners wanted to name the city Lamartine, but Erath convinced them to name the area Waco Village, after the Indians who had lived there.[11] In March 1849, Shapley Ross built the first house in Waco, a double-log cabin, on a bluff overlooking the springs. His daughter Kate was the first settler child to be born in Waco.[12]