It is not uncommon for a patient to present to a physician with the complaint of flushing. Differential diagnoses include menopause, thyrotoxicosis, medications, alcohol, carcinoid syndrome, pheochromocytoma, medullary carcinoma of the thyroid, and systemic mastocytosis.1 Sometimes no cause is identified. In this case report, we describe a family with a novel cause of flushing and diarrhea, most likely the consequence of a hereditary enzymatic defect. Such a disorder may account for some idiopathic cases of flushing and, as illustrated by our subjects, might even be a cause of attention-deficit/hyperactivity disorder (ADHD).
Cheung NW, Earl J. Monoamine Oxidase Deficiency: A Cause of Flushing and Attention-Deficit/Hyperactivity Disorder?. Arch Intern Med. 2001;161(20):2503-2504. doi: