Chronic urticaria is a disease characterized by the formation of an edematous plaque or angioedema, or both, in which mast cells play the main role, mediated by histamine. The widespread distribution of mast cells and histamine receptors in the body has raised the question of whether this release exerts a systemic effect on the body or represents systemic activation without overt organ damage.

Children with chronic urticaria were compared with healthy controls in terms of serum and urine histamine levels, 24-hour ECG rhythm (Holter) and 24-hour ambulatory blood pressure measurement (ABPM).

The mean age of patients with chronic urticaria was 12.4±4.22 years. Systemic symptoms included peptic discomfort (30.3%), palpitations (15.1%), chest pain (9.1%), dyspnea, joint pain and headache. No significant difference was found with regard to serum histamine levels, while urinary histamine levels were higher in the patient group (p=0.164, p<0.001). Urinary histamine levels were significantly higher in patients with peptic symptoms, palpitations, dyspnea and headache (p=0.004, p=0.019, p=0.019, p=0.008, respectively). The SDS values for systolic and diastolic blood pressure in the office were significantly higher in the patient group (p<0.05). Urinary histamine levels were higher in patients with rare ST-T changes in Holter rhythm than in patients without ST-T changes (p=0.04). There was no significant difference between the total and subgroup scores of the quality of life questionnaire, the urticaria activity score of the patient group and their serum and urinary histamine levels (p>0.05).

Determining the systemic symptoms caused by histamine in patients with chronic urticaria may help to create a more effective and aggressive treatment plan in the early stages of the disease and reduce the disease burden. Urinary histamine may be useful in assessing (p>0.05). Chronic exposure, but studies with larger samples are needed to understand its efficacy.