GRAND CAYMAN, CAYMAN ISLANDS – Large doses of nonsedating second-generation antihistamines are at the heart of treating chronic urticaria and will adequately control symptoms in about half of patients.

Dr. Diane Baker, a dermatologist in Portland, Ore. Michele G. Sullivan/MDEdge News

Dr. Diane Baker

But for those who don’t respond, treatment guidelines in both the United States and Europe outline a stepwise algorithm that should eventually control symptoms in about 95% of people, without continuous steroid use, Diane Baker, MD, said at the Caribbean Dermatology Symposium, provided by Global Academy for Medical Education.

The guidelines from the American Academy of Allergy, Asthma & Immunology/American College of Allergy, Asthma, and Immunology, and the European Academy of Allergy and Clinical Immunology [EAACI] and the American Academy of Allergy /Global Allergy are markedly similar, said Dr. Baker, a dermatologist in Portland, Ore.

The U.S. document offers a few more choices in its algorithm, while the European document sticks to a more straightforward progression of antihistamine progressing to omalizumab and then to cyclosporine.

“Both guidelines start with monotherapy of a second-generation antihistamine in the licensed dose. This has to be continuous monotherapy though. We still get patients who say, ‘My hives get better with the antihistamine, but they come back when I’m not taking it.’ Yes, patients need to understand that they have to stay on daily doses in order to control symptoms.”

Drug choice is largely physician preference. A 2014 Cochrane review examined 73 studies of H1-histamine blockers in 9,759 participants and found little difference between any of the drugs. “No single H1‐antihistamine stands out as most effective,” the authors concluded. “Cetirizine at 10 mg once daily in the short term and in the intermediate term was found to be effective in completely suppressing urticaria. Evidence is limited for desloratadine given at 5 mg once daily in the intermediate term and at 20 mg in the short term. Levocetirizine at 5 mg in the intermediate but not short term was effective for complete suppression. Levocetirizine 20 mg was effective in the short term, but 10 mg was not,” the study noted (Cochrane Database Syst Rev. 2014 Nov 14;[11]:CD006137).

“In my practice, we use cetirizine,” Dr. Baker said. “But if a patient is on fexofenadine, for example, and doing well, I wouldn’t change that.”

The treatment guidelines agree on the next step for unresponsive patients: Updosing the antihistamine. “You may have to jump up to four times the recommended dose,” she said. “Sometimes we do this gradually, but sometimes I go right ahead to that dose just to get the patient under control. And there’s good evidence that 50%-75% of our patients will be controlled on an updosing regimen. Just keep them on it until they are symptom free, and then you can try reducing it to see how they do.”

But even this can leave up to half of patients still itching. The next treatment step is where the guidelines diverge, Dr. Baker said. The U.S. document suggests trying several other options, including adding another second-generation antihistamine, adding an H2 agonist, a leukotriene receptor antagonist, or a sedating first-generation antihistamine.

“The European recommendation is to go straight to omalizumab,” Dr. Baker said. “They based this recommendation on the finding of insufficient evidence in the literature for any of these other things.”

Instead of recommending omalizumab to antihistamine-resistant patients, the U.S. guidelines suggest a dose-advancement trial of hydroxyzine or doxepin.

But there’s no arguing that omalizumab is highly effective for chronic urticaria, Dr. Baker noted. The 2015 ASTERIA trial perfectly illustrated the drug’s benefit for patients who were still symptomatic on optimal antihistamine treatment (J Invest Dermatol. 2015 Jan;135[1]:67-75).

The 40-week, randomized, double-blind placebo controlled study enrolled 319 patients, who received the injections as a monthly add-on therapy for 24 weeks in doses of 75 mg, 150 mg, or 300 mg or placebo. This was followed by 16 weeks of observation. The primary endpoint was change from baseline in weekly Itch Severity Score (ISS) at week 12.

The omalizumab 300-mg group had the best ISS scores at the end of the study. This group also met nine secondary endpoints, including a decreased time to reach the clinically important response of at least a 5-point ISS decrease.

The drug carries a low risk of adverse events, with just four patients (5%) in the omalizumab 300-mg group developing a serious side effect; none of these were judged to be related to the study drug. There is a very low risk of anaphylaxis associated with omalizumab – about 0.1% in clinical trials and 0.2% in postmarketing observational studies. A 2017 review of three omalizumab studies determined that asthma is the biggest risk factor for such a reaction.

The review found 132 patients with potential anaphylaxis associated with omalizumab. Asthma was the indication for omalizumab therapy in 80%; 43% of patients who provided an anaphylaxis history said that they had experienced a prior non–omalizumab-related reaction.

The U.S. guidelines don’t bring omalizumab into the picture until the final step, which recommends it, cyclosporine, or other unspecified biologics or immunosuppressive agents. At this point, however, the European guidelines move to a cyclosporine recommendation for the very small number of patients who were unresponsive to omalizumab.

Pivotal trials of omalizumab in urticaria used a once-monthly injection schedule, but more recent data suggest that patients who get the drug every 2 weeks may do better, Dr. Baker added. A chart review published in 2016 found a 100% response rate in patients who received twice monthly doses of 300 mg (J Am Acad Dermatol. 2016 Jun;74[6]:1274-6).

Dr. Baker disclosed that she has been a clinical trial investigator for Novartis.

Global Academy and this news organization are owned by the same parent company.

This article was updated 2/1/19.