Evaluation of coal tar fractions for use in psoriasiform diseases using the mouse tail test. III. High boiling tar oil acids.

Twelve phenolic fractions of creosote and anthracene oils derived from a high temperature tar were applied in an ointment base to mouse tail skin. After treatment with the higher boiling acids, formerly parakeratotic scale areas underwent granular layer induction and 'basket-weave' keratin was produced. Changes in distribution of acid phosphatase and in horny layer fluorescence were consistent with the conversion to an orthokeratotic state. It is suggested that some of these phenols may be of value in the treatment of chronic psoriasis.