Source of Support: None, Conflict of Interest: None
Forty patients of chronic, stable, plaque psoriasis were treated with different concentrations of crude coal tar (CCT) with varied times of application but constant sun exposure. All concentrations with 8-10 hours of application were found to be equally effective. However, shorter period of application (2 hour) resulted in decreased efficacy. An application of white petrolatum was as effective as crude coal tar when combined with sun exposure.