LONGITUDINAL-STUDY OF EXCRETION OF METABOLITES OF POLYCYCLIC AROMATIC-HYDROCARBONS IN URINE FROM 2 PSORIATIC PATIENTS

Coal tar, which is widely used in the treatment of patients with atopi c dermatitis, chronic eczema, and psoriasis, contains a large amount o f polycyclic aromatic hydrocarbons (PAH). Some of the PAH compounds ar e known either to be carcinogenic or to potentiate the effects of othe r carcinogenic substances. In the present study, the excretion pattern s of 1-hydroxypyrene (metabolite of pyrene) and alpha-naphthol (metabo lite of naphthalene) in urine were studied in 2 patients, both treated once a day with coal tar pitch covering more than 50% of the skin. Af ter 1 week of treatment, the concentration of both alpha-naphthol and 1-hydroxypyrene increased approximately 100 times. However, the concen tration after 3 weeks of treatment was decreased to approximately the concentration measured before initiation of the treatment, even though the patients were coal tar-treated with unchanged intensity. The meas ured concentrations of alpha-naphthol and 1-hydroxypyrene in the urine of the 2 patients exceeded by order of magnitude the levels measured in the urine of occupationally exposed workers, and in view of the pre sent study, epidemiological studies are needed to clarify to what exte nt coal tar treatment results in an increased risk of skin cancer, and e.g. bladder cancer.