Redness of the face is one of the manifestations of carcinoid syndrome, but it does not necessarily mean that redness of the face is definitely carcinoid syndrome. Carcinoid syndrome is a syndrome that accompanies tumours and can cause damage to multiple systems, including skin, digestive and respiratory, and is caused by a variety of tumour diseases.
The main manifestations are flushing of the skin; abdominal pain and diarrhoea; hypoglycaemia; cough, coughing, shortness of breath and dyspnoea; precocious puberty and abnormal sex drive. The diagnosis is clear based on a significant increase in 5-hydroxyindoleacetic acid in urine examination, with a normal reference value of <10mg/24h and often >40mg/24h in patients.