 This study will evaluate the efficacy and safety of two concentrations 0.5 percent and 1 and two application frequencies once a day and twice a day of GSK2894512 cream for the topical treatment in adolescent and adult subjects with atopic dermatitis. Results from this study will be considered when selecting the most appropriate concentration of GSK2894512 cream and application frequency in future clinical studies. This is a multicenter United States, Canada, and Japan, randomized, double-blind sponsor-unblind, vehicle-controlled, 6-arm, parallel-group, dose-finding study in adolescent and adult subjects with atopic dermatitis. Two concentrations of GSK2894512 cream 0.5 and 1 and a vehicle control cream will be equally randomized and evaluated following application to all atopic dermatitis lesions except on the scalp once daily evening or twice daily morning and evening for 12 weeks. This study will consist of 3 periods: up to 4 weeks screening, 12 weeks double-blind treatment, and 4 weeks post-treatment follow-up. The total duration of subject participation will be approximately 16 to 20 weeks. Approximately 270 adolescent and adult males and females subjects with atopic dermatitis will be screened in order to have at least 228 randomized subjects 38 subjects for each of the 6 treatment groups and approximately 204 evaluable subjects overall. Approximately 30 subjects will be randomized in Japan to achieve at least 24 evaluable Japanese subjects. 