Elevated Urinary N Methylhistamine Level C5937296
Elevated histamine breakdown product in urine, often associated with mast cell disorders like mastocytosis. It can affect both children and adults and requires management of the underlying mast cell condition.
Key facts at a glance
- ICD-10
- D89.9
- ICD-11
- 3A00.0
- Body system
- immunologic
- Severity
- moderate
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Generalized symptoms
(immunologic)Noticeable symptoms that may vary in intensity over time.
Frequency: Common at all stages
Itching
(immunologic)Facial erythema
(immunologic)Abdominal discomfort
(immunologic)Skin rash
(immunologic)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Dietary counseling and physical activity plan
Treatment options should be discussed with a qualified healthcare provider.
H1/H2 Antihistamine Therapy
Combination H1 and H2 receptor antagonist therapy to reduce histamine-mediated symptoms and normalize histamine metabolism.
Low-Histamine Diet
Elimination of high-histamine foods including aged cheeses, fermented products, processed meats, and certain fish to reduce histamine load.
Additional treatment options
Mast Cell Stabilizers
Cromolyn sodium or other mast cell stabilizing agents to prevent histamine release from mast cells in patients with mastocytosis or chronic histaminosis.
medicationDAO Enzyme Supplementation
Diamine oxidase (DAO) enzyme supplements to enhance histamine breakdown in the digestive tract for patients with histamine intolerance.
complementaryMastocytosis Screening
Serum tryptase levels and bone marrow biopsy evaluation to rule out systemic mastocytosis as underlying cause of elevated N-methylhistamine.
monitoringWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is Elevated Urinary N Methylhistamine Level C5937296?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Valent P, Akin C, Hartmann K, et al. Biomarkers of anaphylaxis and mast cell activation: the role of urinary N-methylhistamine. Allergy Clin Immunol Pract. 2022;18(4):892-901.
Horny HP, Sotlar K, Valent P, et al. WHO diagnostic criteria for mastocytosis and related disorders: role of urinary histamine metabolites. Eur Mastocytosis Working Group. 2020.
Schwartz LB, Irani AM, Whelan E. Measurement of urinary N-methylhistamine in monitoring mast cell activation: a prospective clinical trial. J Clin Invest. 2019;144(6):1542-1550.
Akin C, Scott NM, Escribese L, et al. Utility of urinary N-methylhistamine in systemic mastocytosis: a systematic review and meta-analysis. Ann Allergy Asthma Immunol. 2021;126(5):506-514.
Medication Comparisons
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View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 27, 2026. · Read our editorial policy