Remotely provided open-label placebo reduces frequency of and impairment by allergic symptoms

Placebos being prescribed with full honesty and disclosure (i.e., open-label placebo [OLP]) have been shown to reduce symptom burden in a variety of conditions. With regard to allergic rhinitis, previous research provided inconclusive evidence for the effects of OLP, possibly related to a separate focus on either symptom severity or symptom frequency. Overcoming this limitation of previous research, the present study aimed to examine the effects of OLP on both the severity and frequency of allergic symptoms.In a randomized-controlled trial, patients with allergic rhinitis ( N = 74) were randomized to OLP or treatment as usual (TAU). Because of the COVID-19 pandemic, OLP was administered remotely in a virtual clinical encounter. Participants took placebo tablets for 14 days. The primary outcomes were the severity and frequency of allergic symptoms. The secondary end point was allergy-related impairment.OLP did not significantly improve symptom severity over TAU ( F (1,71) = 3.280, p = .074, η2 = 0.044) but did reduce symptom frequency ( F (1,71) = 7.272, p = .009, η2 = 0.093) and allergy-related impairment more than TAU ( F (1,71) = 6.445, p = .013, η2 = 0.083), reflecting medium to large effects. The use of other antiallergic medication did not influence the results.Although OLP was able to lower the frequency of allergic symptoms and allergy-related impairment substantially, its effects on symptom severity were weaker. The remote provision of OLP suggests that physical contact between patients and providers might not be necessary for OLP to work.