Carcinoid syndrome occurs in about 10% of patients with these tumors. In 75% of patients, episodes of severe flushing are precipitated by exercise, alcohol, stress, and certain foods (spices, chocolate, cheese, avocados, plums, walnuts, red sausage, and red wine). With time the flushing may appear without provocation. The character of the flush differs depending upon the site of origin of the tumor. Tumors of the foregut (stomach, lung, pancreas) are associated with a bright-red “geographic” flush of a more sustained duration, as well as lacrimation (the secretion of tears), wheezing, sweating, and a sensation of burning. In ileal tumors, the flush is patchier and more violet in color, intermingled with areas of pallor, and does not last as long. Flushing of either type may be associated with facial edema that may persist and lead to telangiectasia and even facial rosacea.The patient should receive an adequate niacin supplement (nicotinamide rather than nicotinic acid, since the latter causes flushing) and should avoid foods, agents, and activities that precipitate symptoms.
