Coal Tar Making a Psoriasis Comeback



LAS VEGAS – Topical tar therapy for psoriasis may be making a comeback thanks to more user-friendly formulations.

That trend is happening in Europe and may be replicated in the United States, Dr. Linda Stein Gold said at a dermatology seminar sponsored by Skin Disease Education Foundation (SDEF).

"Topical therapy is the bread and butter of psoriasis treatment," and coal tar has been used for centuries to control the symptoms of plaque psoriasis, said Dr. Stein Gold, director of dermatology research at Henry Ford Hospital, Detroit.

The Goeckerman regimen, a combination of topical tar and ultraviolet light therapy in use since the 1920s, proved "exceptionally" effective and durable, she noted, with an average time of 18 days to 90% clearing of psoriatic lesions and 90% of patients remaining clear for up to 8 months.

But tar therapy was time consuming, a logistical hassle, and aesthetically unpleasing, and its use declined in recent decades with the advent of systemic biologic medications. "People weren't using tar before because it's messy and it smelled. Now we have some better options," Dr. Stein Gold said.

Photo courtesy Dr. Alexa B. Kimball

One of the newer topical solutions is a transparent gel of 15% liquor carbonis distillate (LCD), the equivalent of 2.3% coal tar (Psorent, NeoStrata Co.). "It doesn’t discolor bleached hair" when used for scalp psoriasis, it is quick-drying, and it comes in bottles with "dab-on" applicators, she said.

Photo courtesy Dr. Alexa B. Kimball

In a controlled comparison with calcipotriol cream in 12 weeks of treatment of 60 adults with moderate plaque psoriasis, the LCD solution was more effective and led to fewer relapses 6 weeks after treatment. Among 55 patients with complete data, mean Psoriasis Area Severity Index (PASI) scores improved by 58% in the LCD solution group and 37% in the calcipotriol group, a significant difference (J. Am. Acad. Dermatol. 2009;60:Ab174 [doi: 10.1016/j.jaad.2008.11.757]).

Photo courtesy Dr. Alexa B. Kimball.

Abdominal psoriatic plaque at baseline (top photo) and after 4 (middle photo) and 12 weeks (bottom photo) of twice daily treatment with topical Psorent solution.

A 75% improvement in PASI scores was seen in 11 of 27 (41%) of the LCD solution group and none of the 28 patients on calcipotriol. A 50% improvement in PASI scores was seen in 18 of 27 (67%) in the LCD group and 10 of 28 (36%) in the calcipotriol group. These differences between groups were statistically significant.

Among 42 patients with Physician Global Assessment (PGA) scores 6 weeks after treatment, the PGA scores worsened to baseline in 5 of 22 patients (23%) in the LCD solution group and in 14 of 20 patients (70%) in the calcipotriol group, again a significant difference.

A separate study compared the LCD solution in combination with UVB therapy on one side of the body with UVB light therapy alone on the other side of the body in 12 patients in 4 weeks of therapy. "Very quickly, the combo therapy gets more rapid and complete efficacy compared with UVB alone," said Dr. Stein Gold (J. Drugs. Dermatol. 2009;8 [4]:351-7).

Another relatively user-friendly product is an over-the-counter 2% coal tar formulation in a foam base (Scytera, Promius Pharma). The foam is "a much more cosmetically elegant" treatment compared with older tar therapies, she said. It spreads easily, dries quickly, and has an acceptable fragrance, Dr. Stein Gold added.

In a randomized, observer-blind study of 38 patients with chronic plaque-type psoriasis, two lesions on each patient were treated for 8 weeks with a 1% coal tar foam or calcipotriol cream. The treatments appeared to be comparably effective. More patients reported itching, unpleasant odor or staining with the tar foam than with calcipotriol cream, but the foam is considerably less expensive, the investigators noted (Br. J. Dermatol. 2003;149:350-53).

"Tar is something we probably should look at again," Dr. Stein Gold said.

Other useful topical therapies include corticosteroids, she said. While studies with objective measures of atrophy have proved that potent topical corticosteroids do lead to thinning of the skin over time, often this effect is not clinically noticeable, and it reverses over time once treatment is stopped.

Topical vitamin D is complementary to topical steroids for psoriasis therapy and helps counteract some of the side effects of topical steroids on skin.

Dr. Stein Gold said she has had financial associations with Leo Pharma, Medicis Pharmaceutical Corp., Stiefel Laboratories, Galderma, and Novartis. SDEF and this news organization are owned by Elsevier.

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