Urticaria is a localized edema reaction due to skin and mucosal small blood vessels dilating and increasing permeability. Chronic urticaria refers to a wheal that occurs at least twice a week for no less than 6 weeks1.
The pathogenesis of urticaria is still not fully understood and may involve infection, allergies, pseudo-allergic reactions and autoreactivity. Mast cells play a central role in the pathogenesis, and they activate and degranulate, leading to the release of histamine, leukotrienes, prostaglandins, etc., which are the key factors affecting the occurrence, development, prognosis and therapeutic response2.
The clinical manifestation of urticaria is wheal. The outbreaks are diverse and often accompanied by itching. A few patients may have angioedema. The cause of urticaria, especially chronic urticaria, is unclear, and the condition is recurrent, and prolonged as well. Except for a small number of concurrent respiratory or other systemic symptoms, the majority are benign3.
Drug selection should follow the principles of safe, effective and regular use to improve the quality of life of patients. It is recommended to develop and adjust treatment plans based on the patient's condition and response to treatment. At present, the second-generation non-sedating or low-sedation antihistamines are preferred for first-line treatment. After effective treatment, the dose is gradually reduced to achieve effective control of wheal. For the treatment of acute urticaria, glucocorticoids can be selected when the cause is actively identified and eliminated, and the oral antihistamines are not effective in controlling symptoms.3
1.  Zuberbier T, Asero R,Bindslev-Jensen C, et al. EAACI/GA(2)LEN/EDF/WAO guideline: definition, classification and diagnosis of urticaria[J]. Allergy, 2009, 64(10): 1417-1426.
2.  钟华, 郝飞. 荨麻疹的病理生理与临床[J]. 中华皮肤科杂志, 2007, 40(10): 652-654.
3.  中华医学会皮肤性病学分会. 中国荨麻疹诊疗指南(2014版)[J]. 中华皮肤科杂志, 2014, 47(7): 514-516.