PRAGUE — For psoriasis patients who can handle the smell and mess, coal tar remains an effective, inexpensive treatment option for stable disease, according to Dr. Uma Kumar.
Coal tar proved just as effective as topical tazarotene (Tazorac) in a small randomized study of patients with stable plaque psoriasis. All patients in both groups had either marked or moderate improvement after 12 weeks of treatment.
“Our results indicate that tazarotene 0.1% gel and coal tar 5% ointment appear to have comparable efficacy in stable plaque psoriasis,” Dr. Kumar of the All Indian Institute of Medical Sciences in New Delhi reported at the International Congress of Dermatology.
“Considering the overall cost to benefit ratio in a chronic disease like psoriasis, coal tar ointment is still an effective treatment modality for patients with stable plaque psoriasis, especially in developing countries where the treatment'health care costs are borne by patients themselves,” he said.
The findings came from a comparison of tazarotene gel and crude coal tar in 30 patients with stable plaque psoriasis. The patients had limited disease, defined as involvement of less than 20% of body surface area. Disease duration averaged about 9 years. Before the initiation of randomized treatment, patients completed a 4-week washout period for systemic therapy—2 weeks for topical therapy.
Each patient was treated simultaneously with both agents in an unblinded manner: tazarotene on the right side of the body and coal tar on the left. Treatment continued for 12 weeks, and patients were assessed at 2-week intervals. Response was determined by change in an erythema, scaling, and induration (ESI) score, which averaged about 28 at baseline.
The ESI scores did not differ significantly between treatments at any of the assessments. At 12 weeks, ESI scores averaged 7.1 with tazarotene treatment and 5.9 with coal tar. The mean ESI score for lesions treated with coal tar were lower at 6 and 10 weeks, in addition to the end of the study.
Dr. Kumar reported that 27 patients completed the study. Psoriasis lesions improved by at least 50% in all patients on both sides of the body. Investigators rated the improvement as marked in 41% of tazarotene-treated areas and 59% of areas treated with coal tar. The figures were reversed for moderate improvement.
“Coal tar is one of the commonest conventional treatment modalities for psoriasis,” Dr. Kumar said. “Various studies have proved its effectiveness time and again.
“Patient acceptability is the major problem with coal tar. The preparations are usually greasy and unpleasant smelling, and they can stain clothing,” he noted.
Dr. Kumar and his colleagues reported having no relevant conflicts of interest.