Study of histamine wheal suppression by dexamethasone with and without iontophoresis

Background: Iontophoresis increases the penetration of drugs into the skin by electric current. The ability of topical steroids to reduce the size of the histamine wheal was used to assess the efficacy of topical dexamethasone delivered with and without iontophoresis. Aim: To determine the wheal suppressing ability of dexamethasone delivered with and without iontophoresis. Methods: A template with three squares of 3 x 3 cm was placed on both forearms of 20 volunteers and the edges marked. A gauze piece soaked in 2 ml of dexamethasone solution was placed on the flexor aspect of the left forearm and the electrode, an aluminum foil was placed on it and connected to the negative pole (since dexamethasone is negatively charged). An electric current was passed for 15 minutes. Similarly, on the right forearm, a dexamethasone soaked gauze piece was placed without iontophoresis. Histamine wheal suppression was assessed at the end of 30 min, 1 hr and 2 hrs, on both sides. Statistical analysis was done using an independent t-test. Results: There was a statistically significant difference in wheal suppression at 30 min ( p =0.006) on the left hand where iontophoresis was used. Conclusion: Our experiment showed that topical dexamethasone with iontophoresis has the maximum effect at the end of 30 minutes and is more effective than dexamethasone without iontophoresis.