Are oral H1 antihistamines effective add-on therapy to topical treatments for eczema?
In children with eczema, there is no evidence to support the addition of oral H1 antihistamines to standard treatment regimens. In adults, the use of fexofenadine (Allegra), 120 mg per day, improves patient-assessed eczema symptoms compared with placebo (number needed to treat = 11; 95% CI, 5.5 to 255).1 (Strength of Recommendation: B, based on inconsistent or limited-quality patient-oriented evidence.)
Eczema (atopic dermatitis) is a chronic inflammatory skin condition resulting in an itchy, red rash that affects roughly 31.6 million people in the United States.2 The disease occurs in 13% of children and 7% of adults,3,4 and significantly affects quality of life. Patients with eczema report that the disease causes embarrassment and frustration and interferes with daily activities, and children report being bullied in school.5,6 Conventional eczema treatment involves topical emollients, corticosteroids, and immunomodulators. However, some patient resources mention oral antihistamines as a possible treatment option.7,8
This Cochrane review included 25 randomized controlled trials with 3,285 participants (1,344 adults and 1,941 children).1 In total, 13 oral H1 antihistamines were studied. Primary outcomes included change in patient-assessed symptoms of eczema and the adverse effect rate reported by participants. Secondary outcomes included change in physician-assessed clinical signs of eczema, change in patient-reported quality of life, and number of eczema flare-ups. The authors reported the effects from specific trials instead of pooling the data because the studies used different oral H1 antihistamines, topical agents (mostly different potency corticosteroids), and durations of treatment.
The reviewers found no evidence demonstrating improvement in primary or secondary outcomes with the use of cetirizine (Zyrtec) or loratadine (Claritin) in children or adults. Reported adverse effects did not differ between treatment and placebo groups. Moderate-quality evidence revealed a small reduction in patient-assessed eczema symptoms (mean difference = –0.25; 95% CI, –0.43 to –0.07; P = .006) with the use of fexofenadine, 120 mg per day, in adults. Acrivastine, azelastine (Astelin), chlorpheniramine, chlorpheniramine maleate, hydroxyzine, ketotifen (Zaditor), and levocetirizine (Xyzal) were not found to be helpful as add-on therapy for eczema.
Topical moisturizers, corticosteroids, and immunomodulators continue to be the main treatments for eczema. The low quality of evidence and lack of standardization among the studies made the pooling of data difficult; nonetheless, the evidence suggests that most oral H1 antihistamines have no role in the treatment of eczema. Neither the 2018 consensus-based European guidelines for the treatment of atopic eczema nor the 2014 American Academy of Dermatology atopic dermatitis guidelines mentions the use of oral H1 antihistamines in this patient population.9,10 They do, however, warn against the use of topical antihistamines. The European guidelines state that there is insufficient evidence to demonstrate the effectiveness of oral H1 antihistamines, and the American Academy of Dermatology does not support their routine use.