CU, one of the most frequent skin allergy diseases, is a heterogeneous condition, and prognostic factors for each treatment are not well known. Symptomatic treatment for CU is the most frequently used form of management, and a step-wise approach is recommended.19
First-line therapy with an antihistamine-based regimen may not achieve satisfactory control in 5% to as many as 50% of patients with CU.24,25
Those with refractory CU require the addition of cyclosporine, dapsone, or omalizumab to H1-antihistamines, and frequent exacerbations are treated with systemic steroids. However, the toxicities and adverse events associated with cyclosporine and long-term steroid exposure should be considered carefully.19,26
Thus, a continuing need exists for effective and safe treatments for refractory CU; trials of several novel therapeutics are in progress.
Recent studies have demonstrated favorable effects of omalizumab in patients with refractory CU. Omalizumab significantly improved the UAS, health-related QOL, and medication use, with a rapid onset of effects that persisted for the duration of treatment.15,16,20,27
The onset of effects occurred after 1-2 weeks,15
and greater than 50% improvement in health-related QOL was noted.15,20
In the present study, when we analyzed 26 patients with refractory CU, the effects, including improvement in the UAS, CU-QOL score, and medication use, were comparable to previous findings.15-17,20
However, in eight patients, urticaria symptoms recurred during the treatment period, and medications had to be restarted to control the symptoms, which in half of these subjects recurred at week 24. These findings suggest that although long-term study results are needed, omalizumab may be considered as an alternative regimen for controlling refractory CU in patients who do not respond to conventional treatments.
A longer duration of disease, concurrent angioedema, the combination with physical urticaria, and a positive autologous serum skin test (ASST) are related to severe CU.28,29
While all patients with mild CU were symptom-free after 2 years, more than 30% of patients with moderate-to-severe symptoms appeared to continue to suffer at 5 years.29
At least 50% of patients with CU have angioedema,30
one-third show a positive response on the ASST,31,32
and the prevalence of CU in combination with physical urticaria is 10% to 50%.33,34
These patients were more severely affected and had a longer disease duration.30,33,34
Generally, omalizumab could induce clinical remission in 50%-70% of Western patients with CU.15,20
However, no report has suggested any prognostic factors for predicting the response to omalizumab. In the present study, 53.8% of the patients achieved remission after omalizumab treatment, and half of them exhibited angioedema and physical urticaria. The presence of angioedema, physical urticaria, and the duration of disease were not related to treatment response. Instead, we found a significantly higher prevalence of personal or family history of allergic diseases in the remitted group than in the non-remitted group, indicating that a personal or family history of allergic diseases may be a favorable factor for predicting remission after omalizumab treatment in refractory CU.
Neither severe adverse reactions nor death have been reported in previous studies. Kaplan et al.15
reported no adverse effects. In another study, the rate of adverse events was similar between the omalizumab and placebo groups; the most frequent adverse events were diarrhea, followed by nasopharyngitis, upper respiratory infection, and headache.20
In the present study, minimal adverse reactions were reported in four cases, and no patient discontinued omalizumab treatment.
In conclusion, omalizumab is an effective and safe treatment for patients with refractory CU. The findings suggest that a personal or family history of allergic diseases may be a favorable factor for predicting remission. Further studies will be needed to investigate potential factors for differentiating favorable and unfavorable responders.