Histamine Intolerance: A Pioneering Report on the Oral Manifestations of a Complex Systemic Disorder

Histamine intoxication, initially described as scombroid fish poisoning, is now recognized as histamine intolerance (HIT), a condition associated with impaired histamine metabolism, often due to diamine oxidase (DAO) deficiency. HIT presents with nonspecific gastrointestinal and systemic symptoms, frequently overlooked in clinical practice. While extraintestinal manifestations are well-documented, oral findings have not been previously described.

This short communication presents the first reported cases of HIT diagnosed through oral lesions, providing a brief review of this emerging condition.

Five patients (2022-2024) were evaluated based on clinicopathological findings and dietary anamnesis, focusing on histamine-rich food intake. A thorough oral examination was conducted, and diagnostic criteria and differential diagnoses were reviewed.

All cases exhibited persistent oral burning, sensitivity to acidic foods, and erythematous velvety macules on oral mucosa. Symptoms correlated with histamine intake and improved with dietary restriction and antihistamines. Differential diagnoses included food allergies, plasma cell mucositis, fungal infections, lupus, and oral lichen planus. A familial case suggests a genetic component of DAO deficiency.

Recognizing oral lesions as potential HIT manifestations may improve diagnostic accuracy in patients with unexplained mucosal symptoms. Further research is needed to establish standardized diagnostic criteria and optimize clinical management.