Objective

The aim of this study was to compare the efficacy of halobetasol propionate 0.05% ointment administered once daily with that of the ointment administered twice daily in combination with 12% ammonium lactate lotion for treatment of plaque psoriasis. A second objective was to investigate the benefits of maintenance therapy with ammonium lactate 12% lotion.

Design

The study was a randomized, investigator-masked, parallel trial. In the first phase, subjects applied halobetasol 0.05% ointment either once or twice daily in combination with 12% ammonium lactate lotion twice daily for 2 weeks. In the second phase, subjects either continued ammonium lactate twice daily or discontinued all treatment for 4 weeks.

Setting

University of California San Francisco Psoriasis and Skin Treatment Center. Participants: The study comprised 40 patients with a target plaque of at least 1 cm² and a Psoriasis Severity Assessment (PSA) score of at least 6.

Measurements

Plaque induration, scale, and erythema were recorded at weeks 0, 1, 2, 4, and 6. Paired t-tests compared improvement between the two groups; unpaired t-tests compared differences between the two arms.

Results

No significant difference was noted in efficacy between once- and twice-daily halobetasol application at weeks 0 and 2 for induration (respectively, P = 0.10 and P = 0.21), scale (P = 0.49 and 0.51), erythema (P = 0.42 and 0.14), and total PSA (P = 0.37 and 0.23). A significant difference was found in scale between weeks 2 and 4 (P = 0.04) and weeks 2 and 6 (P = 0.03) in favor of patients continuing ammonium lactate lotion.

Conclusion

Once-daily halobetasol ointment achieves results similar to those of twice-daily application when used with ammonium lactate lotion in plaque psoriasis treatment. Sequential therapy with 2-week halobetasol ointment followed by twice-daily ammonium lactate may enhance therapeutic duration.