A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and therefore treatments for rashes, vary widely. Diagnosis must take into account such things as the appearance of the rash, other symptoms, what the patient may have been exposed to, occupation, and occurrence in family members. The diagnosis may confirm any number of conditions.

The presence of a rash may aid associated signs and symptoms are diagnostic of certain diseases. For example, the rash in measles is an erythematous, morbilliform, maculopapular rash that begins a few days after the fever starts. It classically starts at the head and spreads downwards.

Common causes of rashes include:

Uncommon causes:

The causes of a rash are extremely broad, which may make the evaluation of a rash extremely difficult. An accurate evaluation by a provider may only be made in the context of a thorough history (What medication is the patient taking? What is the patient's occupation? Where has the patient been?) and complete physical examination.

James “Jim” Rash (born July 15, 1970) is an American actor, comedian, producer, and Academy Award-winning screenwriter.

Rash was born in Charlotte, North Carolina. He graduated from Charlotte Latin School in Charlotte, and after graduating there spent a post-graduate year at the Lawrenceville School, located in Lawrenceville, New Jersey.

Rash played Mr. Grayson/Stitches, a sidekick to the supervillain 'Royal Pain' in the 2005 film Sky High and as the recurring characters Fenton on That '70s Show, and "Andrew the Whore House Guy" on Reno 911!. He also guest starred in the last episode of Friends, and played the role of Head T.A. Philip in Slackers. Rash currently is a series regular on Community as Dean Pelton after being a recurring character the first two seasons.

Rash and comedy partner Nat Faxon have recently moved into screenwriting. Their screenplay, based on Kaui Hart Hemmings' novel The Descendants, was on the 2008 edition of the Black List, a list of the most popular unproduced scripts in Hollywood.The film was produced in Hawaii, directed by Alexander Payne and starring George Clooney, and was released on November 18, 2011 to critical acclaim. Payne, Faxon and Rash received a Golden Globe nomination and won an Academy Award for their work.

Craig Ferguson (born 17 May 1962) is a Scottish-American television host, stand-up comedian, writer, actor, director, author, and producer. He is the host of The Late Late Show with Craig Ferguson, an Emmy Award-nominated, Peabody Award-winning late-night talk show that airs on CBS. In addition to hosting that program and performing stand-up comedy, Ferguson has written two books: Between the Bridge and the River, a novel, and American on Purpose, a memoir. He became a citizen of the United States in 2008.

Before his career as a late-night television host, Ferguson was best known in the United States for his role as the office boss, Nigel Wick, on The Drew Carey Show from 1996 to 2003. He also wrote and starred in three films, directing one of them.

Ferguson was born in the Stobhill Hospital in the Springburn district of Glasgow, Scotland to Robert and Janet Ferguson, and raised in nearby Cumbernauld, growing up "chubby and bullied". When he was six months old, he and his family moved from their Springburn apartment to a council house in Cumbernauld. They lived there as Glasgow was re-housing many people following damage to the city from World War II. Ferguson attended Muirfield Primary School and Cumbernauld High School. At age sixteen, Ferguson dropped out of Cumbernauld High School and began an apprenticeship to be an electronics technician at a local factory of American company Burroughs Corporation.