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Abnormalities in histamine pharmacodynamics in chronic urticaria
G Kanny1, D A Moneret-Vautrin, H Schohn
1Service de Médecine D, Immunologie Clinique et Allergologie, Centre Hospitalier Universitaire de Nancy, Hôpital de Brabois, France.
Summary
Patients with chronic urticaria (CU) show abnormal histamine metabolism after a digestive histamine challenge (DHC). This suggests impaired histamine breakdown, potentially due to a diamine oxidase (DAO) deficit, contributing to CU development.
Area of Science:
- Immunology
- Gastroenterology
- Dermatology
Background:
- Histamine is implicated in chronic urticaria (CU) pathogenesis.
- Exogenous histamine metabolism in CU patients is not fully understood.
Purpose of the Study:
- To investigate the effects of ingested histamine on CU patients.
- To assess histamine and methylhistamine levels following a digestive histamine challenge (DHC).
Main Methods:
- 25 CU patients underwent duodenal histamine instillation (120 mg).
- Plasma histamine (H) and methylhistamine (MH) levels were measured.
- Urinary MH and flow rates were analyzed.
Main Results:
- 64% of CU patients developed urticaria post-DHC; controls remained asymptomatic.
- Elevated plasma histamine levels were observed in 72% of CU patients.
- Increased urinary MH and flow rates correlated with urticaria attacks.
Conclusions:
- CU patients exhibit disturbed exogenous histamine metabolism, likely due to intestinal hyperpermeability or reduced enzymatic catabolism.
- A deficit in enterocyte diamine oxidase (DAO) is postulated.
- Skin reactivity to histamine varies individually.