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Posted By: Amanda Michaud, MMS, PA-C
July 24, 2020
Chronic idiopathic urticaria (CIU), also called chronic spontaneous urticaria (CSU), is a condition when urticaria, or hives, are present for more than 6 weeks. Unlike acute urticaria, chronic urticaria is unlikely to be caused by a specific offending agent such as a food, drug, or other allergen. The cause and pathogenesis of CSU is unknown.
The diagnosis of CSU is clinical. It requires at least 6 weeks of pruritus, as well as red, raised, and well-circumscribed lesions that vary in size and location. Individual lesions typically do not last more than 24 hours in one location and disappear without any bruising or skin changes. Approximately 40% to 50% of patients have associated angioedema.
Many patients who have CSU are fixated on an allergic trigger. It's important to educate them on the difference between acute urticaria seen in allergic reactions versus chronic hives. Routine laboratory evaluation for CSU, in absence of other symptoms, is not indicated. While there is an association between CSU and autoimmunity, labs to evaluate for other conditions such as Hashimoto's thyroiditis or lupus should only be done in the presence of symptoms specific for those disease states. If there is associated bruising or skin changes, skin biopsy should be completed to assess for vasculitis. Food allergy panels are not recommended.
Pruritus in CSU can be severe, and the associated skin appearance and lack of sleep can lead to significant psychosocial distress. Thankfully, there are several safe and effective treatment options for patients with CSU.
First-line treatment includes nonsedating, second- or third-generation antihistamines (eg, cetirizine, levocetirizine, fexofenadine) taken 2 to 4 times per day. If the symptoms improve, the dose can be decreased as tolerated. If additional symptom control is needed, some guidelines recommend adding a twice-daily H2-blocker such as famotidine or a leukotriene antagonist, but there is quite weak evidence that these medications are effective. Additionally, sedating, first-generation antihistamines such as diphenhydramine or hydroxyzine can be utilized, especially at bedtime.
The consensus for patients inadequately controlled on antihistamines is to start omalizumab 300 mg every 4 weeks. Clinical trials have demonstrated significant symptom improvement with omalizumab in patients with CSU; 52% had clinical response and 34% were hive-free by week 12 (3 doses). It has also been shown that 81% of patients on combined oral antihistamines and omalizumab will have clearance of hives. Unfortunately, there are some patients who do not respond to omalizumab; other treatment options can be utilized, with cyclosporine being the most widely used, followed by dapsone, methotrexate, sulfasalazine, hydroxychloroquine, gamma globulin infusions, or long tapers of oral corticosteroids.
Overall, proper identification and treatment of CSU can eliminate unnecessary testing, patient anxiety, and reduce healthcare costs. Further, by following established treatment guidelines, patients with CSU will have improved clinical outcomes.
- Kaplan AP. Therapy of chronic urticaria: a simple, modern approach. Ann Allergy Asthma Immunol. 2014;112:419-425.