Effect of coadministration of corticosteroids on the development of contact sensitization

Background: Transdermal administration of drugs can increase patient compliance and reduce side effects, but it can also cause contact sensitization. Corticosteroids frequently are used to suppress the local immune response; however, their use as a pretreatment for transdermal system application sites is not practical. Objective: Our purpose was to determine the feasibility of suppressing contact sensitization by delivering a corticosteroid with the transdermal delivery systems. Methods: Materials were applied continuously for 3 weeks to the same (protocol SS) or different (protocol AS) skin sites. Skin flux and appearance of sensitization were determined. Results: Coadministration of hydrocortisone reduced the incidence of sensitization by d-chlorpheniramine and benzoyl peroxide from 45% to 7.5% and from 20% to 2.3%, respectively, under protocol SS. Under protocol AS, sensitization by d-chlorpheniramine was reduced from 15% to 1%. Frequent exposure to the sensitizer plus corticosteroid induced tolerance to the sensitizer. Conclusion: Sensitization by moderately immunogenic drugs after any length of exposure may be reduced to acceptable levels by the coadministration of hydrocortisone.