Histamine intolerance is a condition where the body cannot effectively eliminate histamine, leading to a range of symptoms. The condition is influenced by genetic factors, dietary intake, and medications that affect diamine oxidase (DAO), an enzyme responsible for breaking down histamine. Symptoms include gastrointestinal, skin, respiratory, and cardiovascular issues, often mimicking allergic reactions. Diagnosis remains challenging due to the non-specific nature of symptoms and lack of a single definitive test. Serum DAO levels are used as a potential marker, but its reliability is debated. Diagnosis often involves a combination of clinical evaluation, symptom assessment, and tests like DAO measurement or histamine challenge tests. Management primarily involves a low-histamine diet, avoiding foods high in histamine, and DAO supplementation. Antihistamines and other medications may be used in some cases. Research highlights the need for better diagnostic tools, standardized criteria, and more robust clinical trials to improve understanding and treatment of histamine intolerance. Future directions include exploring genetic factors, environmental influences, and novel therapeutic targets to enhance diagnosis and management. Overall, histamine intolerance is a complex condition requiring multidisciplinary approaches for effective management.Histamine intolerance is a condition where the body cannot effectively eliminate histamine, leading to a range of symptoms. The condition is influenced by genetic factors, dietary intake, and medications that affect diamine oxidase (DAO), an enzyme responsible for breaking down histamine. Symptoms include gastrointestinal, skin, respiratory, and cardiovascular issues, often mimicking allergic reactions. Diagnosis remains challenging due to the non-specific nature of symptoms and lack of a single definitive test. Serum DAO levels are used as a potential marker, but its reliability is debated. Diagnosis often involves a combination of clinical evaluation, symptom assessment, and tests like DAO measurement or histamine challenge tests. Management primarily involves a low-histamine diet, avoiding foods high in histamine, and DAO supplementation. Antihistamines and other medications may be used in some cases. Research highlights the need for better diagnostic tools, standardized criteria, and more robust clinical trials to improve understanding and treatment of histamine intolerance. Future directions include exploring genetic factors, environmental influences, and novel therapeutic targets to enhance diagnosis and management. Overall, histamine intolerance is a complex condition requiring multidisciplinary approaches for effective management.