Comparison of skin concentrations following topical versus oral corticosteroid treatment: reconsidering the treatment of common inflammatory dermatoses.

BACKGROUND

Topical corticosteroids are often considered to have greater safety and poorer efficacy than oral corticosteroids in treating psoriasis and atopic dermatitis. There are limited data for assessing relative efficacy of topical and systemic corticosteroids, however. The concentration of corticosteroid in skin, adjusted for the relative potency of the active compound, may be a predictor of clinical efficacy and can be estimated for both topical and oral administration.

PURPOSE

To analyze the assumption that oral corticosteroid therapy should be more potent than topical therapy by comparing relative corticosteroid concentrations in the skin expected with topical versus systemic administration.

METHODS

The estimated skin concentration of prednisone following oral dosing was calculated based on data showing 70-100% bioavailability and an even tissue distribution. Data on the concentration of corticosteroids found in skin after topical application were obtained from the literature. The relative potencies of corticosteroid molecules were then used to compare skin concentrations of corticosteroid following topical versus oral treatment.

RESULTS

Data derived from the existing literature demonstrated that hydrocortisone 2.5% ointment, triamcinolone 0.1% ointment, and clobetasol 0.05% foam achieved effective skin concentrations greater than the effective concentration achieved by oral prednisone. Betamethasone 0.1% cream achieved effective concentrations in skin within the range created by oral prednisone.

LIMITATIONS

This analysis was limited by the paucity of data regarding cutaneous concentrations of corticosteroids after topical application, and by the differing experimental designs utilized in the available studies.

CONCLUSION

Most topical corticosteroids have the potential to achieve greater effective drug levels in the superficial layers of skin than those achieved with standard doses of oral prednisone. The apparently greater efficacy of oral corticosteroid therapy may be attributable, in part, to poor patient compliance with topical therapy. Systemic alterations in immune function following oral, but not topical, corticosteroid use may also play a role.