This study evaluated the short- and long-term effects of the modified Ingram regimen in widespread plaque psoriasis. A group of 22 patients were evaluated at regular intervals for 210 days using the psoriasis area and severity index (PASI) score and a psoriatic histological value (PHV). Of the 22 patients, 4 were lost to follow-up after day 70, 4 were withdrawn due to therapy failure, and 14 completed the final evaluation at day 210. This trial confirmed the effectiveness of the Ingram regimen in inducing remission in patients with widespread plaque psoriasis. A post-treatment steady-state was identified clinically and histologically.