Background: Adherence to subcutaneous biologic agents for the treatment of psoriasis can be negatively influenced by injection pain.Objective: To explore the differences in injection site pain when patients are pre-treated with heat or cold, versus no pre-treatment prior to administration of a subcutaneous biologic agent.Methods: In an observational cohort study, patients receiving subcutaneous injections of ustekinumab were randomly assigned to receive pretreatment with ice, heat, or no intervention over three visits. Post-dose, patients rated pain on a 100 mm visual analogue scale (VAS).Results: There was an increase in the VAS score for both heat (2.51, P=0.30) and ice (3.33, P=0.16), compared to no intervention. No differences were found between the two intervention groups (-0.83, P=0.73). On average, females had the same VAS scores with ice compared to that of no intervention (-0.12, P=0.97) and a non–significant decrease of 3.29 points (P=0.38) with heat. Males had increased pain scores by 5.65 points (P=0.07) with ice and by 6.39 points (P=0.04) with heat.Limitations: Pain is a subjective measurement and objective quantification is difficult.Conclusions: On average, neither heat nor cold application reliably reduced pain. Our results do not support the application of heat or cold prior to ustekinumab injection.
