A NEW AQUEOUS DITHRANOL GEL FOR PSORIASIS - COMPARISON WITH PLACEBO AND CALCIPOTRIOL OINTMENT

A new aqueous dithranol gel has been developed to reduce irritation an d staining by minimizing unwanted dithranol residue on the skin surfac e. Left-right paired comparisons were conducted vs placebo (phase I) i n 12 inpatients and vs calcipotriol ointment (phase II) in 25 inpatien ts with symmetrical chronic plaque psoriasis to assess its efficacy an d acceptability. In phase I, dithranol gel was significantly better th an the placebo after 4 weeks treatment for each severity parameter, er ythema, scale and palpability (P less than or equal to 0.022). Combine d severity scores (maximum 9) fell from 6.3 to 1.1 with dithranol and to 4.1 with placebo. In phase II, calcipotriol produced significantly greater improvement after 3 weeks than dithranol gel, but there was no difference after 4 weeks by which time severity scores fell from 6.3 to 2.2 with dithranol and to 1.8 with calcipotriol. There was a greate r reduction in psoriasis area (P = 0.04) with calcipotriol but no over all difference in the patients' assessment of effectiveness for either treatment after 4 weeks use. At 4 and 12 weeks follow-up there was no objective difference in severity, although more patients thought that the caldpotriol-treated sites showed greater deterioration. Calcipotr iol caused less irritation and staining than dithranol gel (P < 0.001) . Dithranol in an aqueous gel formulation was effective for inpatient treatment of chronic psoriasis and acceptable for patients, but showed a higher incidence of irritation and staining than calcipotriol ointm ent.