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Published on: October 7, 2017
Reducing transcranial direct current stimulation-induced erythema with skin pretreatment: considerations for
Fabiana Guarienti1,2, Wolnei Caumo2, Pedro Shiozawa1,3
1Service of Interdisciplinary Neuromodulation & Interdisciplinary Center for Applied Neuromodulation, Department and Institute of Psychiatry, University Hospital, University of São Paulo, São Paulo, Brazil.
Objectives:
Transcranial direct current stimulation (tDCS)-induced erythema (skin reddening) has been described as an adverse effect that can harm blinding integrity in sham-controlled designs. To tackle this issue, we investigated whether the use of topical pretreatments could decrease erythema and other adverse effects associated with tDCS.
Materials And Methods:
Thirty healthy volunteers were recruited, and four interventions were applied 30 min prior to tDCS in a Latin square design: placebo, ketoprofen 2%, hydroxyzine 1%, and lidocaine 5%. TDCS was applied for 30 min (2 mA, anode and cathode over F3 and F4, respectively) in two active sessions with a minimum 1-week interval. The Draize erythema scoring system scale was used to assess erythema intensity; a tDCS questionnaire was used to assess other adverse effects (e.g., tingling, itching, burning sensation, and pain).
Results:
We found that ketoprofen (but not hydroxyzine or lidocaine) significantly attenuated tDCS-induced erythema regarding intensity and duration, with a medium effect compared with placebo. Erythema was overall mild, short-lived (lasting 18-24 min after tDCS ending), and more intense under the anode. Subjects with darker skin color also tended to present less intense tDCS-induced erythema. The prevalence of other adverse effects was low and did not differ between dermatological groups.
Conclusions:
Ketoprofen 2% topical pretreatment might be an interesting strategy to reduce tDCS-induced erythema and might be useful for blinding improvement in further sham-controlled tDCS trials.
