A clinicopathologic study of ten patients with recurrent unexplained flushing.

We describe the clinicopathologic features of 10 patients with recurrent unexplained flushing. These patients were referred to the National Institutes of Health with a diagnosis of mastocytosis or idiopathic anaphylaxis. Both diagnoses were eliminated after evaluation. Patients reported attacks of flushing lasting 15 minutes to 2 days and associated with such symptoms as anxiety, chest tightness, paresthesia, slurred speech, weakness, and pruritus. Abdominal pain was a constant feature, often associated with cramping and an increase in stool frequency. Attacks witnessed by physicians consisted of an exaggerated blush response of the face and upper part of the chest, and were sometimes associated with tachycardia, mild hypertension, and tachypnea. Hives, angioedema, wheezing, and hypotension were not observed. Routine laboratory studies and 5-hydroxyindoleacetic acid, vanillylmandelic acid, and plasma histamine levels were normal. Plasma histamine levels did not elevate during attacks. When performed, results of bone marrow examinations, skin biopsies, and bone scans were normal. Psychiatric examinations frequently revealed somatization disorders. Patients had often been prescribed a wide variety of medications including antihistamines, nonsteroidal anti-inflammatory drugs, and steroids, with little or no benefit. Despite the benign nature of the clinical and laboratory findings, patients had undergone repeated, often invasive, examinations for several years. Whether such patients have a prominent flush response exaggerated through a somatization disorder or a relatively benign flushing disorder associated with putative mediator release remains to be determined. Recognition of this category of patients with unexplained flushing will avoid subjecting such patients to unwarranted repeated examinations, procedures, and inappropriate therapy.