Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itch leads to a scratch reflex.Unmyelinated nerve fibers for itch and pain both originate in the skin; however, information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract. Classification
Most commonly, an itch is felt in one place. If it is felt all over the body, then it is called generalized itch or generalized pruritus.If the sensation of itching persists for six weeks or longer, then it is called chronic itch or chronic pruritus. Chronic idiopathic pruritus or essential pruritus is a rare form of itch that persists for longer than six weeks, and for which no clear cause can be identified. Signs and symptoms
Pain and itch have very different behavioral response patterns. Pain elicits a withdrawal reflex, which leads to retraction and therefore a reaction trying to protect an endangered part of the body. Itch in contrast creates a scratch reflex, which draws one to the affected skin site. Itch generates stimulus of a foreign object underneath or upon the skin and also the urge to remove it. For example, responding to a local itch sensation is an effective way to remove insects from ones skin.
A tracheoesophageal fistula (TEF, or TOF; see spelling differences) is an abnormal connection (fistula) between the esophagus and the trachea. TEF is a common congenital abnormality, but when occurring late in life is usually the sequela of surgical procedures such as a laryngectomy. Presentation
Tracheoesophageal fistula is suggested in a newborn by copious salivation associated with choking, coughing, vomiting, and cyanosis coincident with the onset of feeding. Esophageal atresia and the subsequent inability to swallow typically cause polyhydramnios in utero. Rarely it may present in an adult. Complications
Surgical repair can sometimes result in complications, including:
Stricture, due to gastric acid erosion of the shortened esophagus
Leak of contents at the point of anastomosis
Recurrence of fistula
Gastro-esophageal reflux disease
Dysphagia
Asthma-like symptoms, such as persistent coughing/wheezing
Recurrent chest infections
Tracheomalacia

Associations
Neonates with TEF or esophageal atresia are unable to feed properly. Once diagnosed, prompt surgery is required to allow the food intake. Some children experience problems following TEF surgery; they can develop dysphagia and thoracic problems. Children with TEF can also be born with other abnormalities, most commonly those described in VACTERL association - a group of anomalies which often occur together, including heart, kidney and limb deformities. 6% of babies with TEF also have a laryngeal cleft. Cause
Congenital TEF can arise due to failed fusion of the tracheoesophageal ridges after the fourth week of embryological development.A fistula, from the Latin meaning a pipe, is an abnormal connection running either between two tubes or between a tube and a surface. In tracheo-esophageal fistula it runs between the trachea and the esophagus.