Chronic idiopathic urticaria: autologous skin tests and treatment

Abstract

BackgroundChronic urticaria is defined as urticaria persisting daily or almost daily for more than 6 weeks. It affects 0.1% of the population. Intradermal injection of autologous serum and plasma elicits a cutaneous reactivity in almost 45-60% of patients with chronic idiopathic urticaria (CIU). Activation of coagulation process seems to play an important role in the pathogenesis of CIU. Oral anticoagulant therapy has been shown to be effective in the treatment of CIU.ObjectiveThe aim of this study was to evaluate and compare autologous serum skin test (ASST) and autologous plasma skin test (APST) in the diagnosis of CIU and to determine the effect of treatment with antihistamine (loratadine) and anticoagulant (dipyridamole).Patients and methodsThis study included 30 patients suffering from CIU. All patients were subjected to intradermal testing with their serum (ASST) and their plasma (APST). The patients were classified into three equal groups, according to treatment: 10 patients were treated with loratidine, 10 patients were treated with dipyridamole, and 10 patients were treated with combination of loratidine and dipyridamole for 1 month. Follow-up for the three groups was carried out at the first, second, and fourth week of treatment evaluating the effectiveness and adverse effects of drugs. Assessment of the symptom score reduce index (SSRI) in positive and negative ASST and APST patients was evaluated.ResultsThe ASST was positive in 40% of patients, whereas APST was positive in 90% of patients. Loratadine, dipyridamole, and combination of both were effective in the management of patients with CIU. However, best results occurred with combination of both. No serious side effects of treatment were encountered.ConclusionBoth ASST and APST can be used for diagnostic purposes in patients with CIU. APST is superior to ASST in diagnosis of CIU. Combined treatment with antihistamines and anticoagulants provides an effective management of chronic urticaria in positive autologous serum and plasma skin tests patients.