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The objective of this study was to compare the clinical efficacy and acceptability of two dithranol creams (Micanol and Amitase) in patients with plaque type psoriasis treating themselves daily at home. Thirty-five patients started with Amitase (0.1%) and 37 with Micanol (0.1%) applied at night in this 6-week single-blind parallel groups comparison study. Patients who responded more slowly than a theoretically estimated "standard" rate of improvement had their concentration increased to 0.25% at the visit after 2 or 4 weeks. By the end of the study slightly more than half of the number of patients remained on 0.1%. There was no difference between the treatment groups. In comparison with the level at start the composite sign severity score for patients in the Amitase group was reduced by 24% after 1 week, 36% after 2 weeks, 49% after 4 weeks and 62% after 6 weeks. The reduction in the Micanol group was similar. Patients in the Micanol group showed after 1 week of treatment more irritative reactions than patients in the Amitase group. At all follow-up visits, staining of perilesional skin was more prevalent in the Micanol group. Staining of clothing was, however, far more prevalent and severe for patients given the Amitase cream. It may be concluded that Micanol is an important alternative for home treatment of psoriasis.

The clinical effect, side effects, cosmetic properties and the patients preference between Micanol and other dithranol formulations were investigated in three separate studies combining UV-B phototherapy and a short contact dithranol regimen. Good clinical results without difference between Micanol and other dithranol formulations were obtained. Side effects, cosmetic properties and preferences were mostly in favor of Micanol. Therefore, a high patient compliance can be obtained with the new dithranol formulation.

A new dithranol formulation (Dithranol-Biogram), in which the dithranol is microencapsulated by crystalline monoglycerides, has been developed. This stable formulation has pharmaceutical and cosmetic properties which overcome several draw-backs associated with conventional dithranol preparations. The clinical efficacy and side-effects of Dithranol-Biogram were compared to a conventional ex-tempore formulation in the treatment of 33 patients at a day-care centre. The study was designed as a randomized, single-blind, within-patient comparison. Patients were treated 4 times weekly for up to 6 weeks. Each session started with suberythematous UV-B doses followed by application of 1% dithranol for 20 min. There was no difference in clinical efficacy between treatments. Within 2-6 weeks the lesions in 21 of the 33 patients were classified as healed. The average reduction in severity score was 39%, 62% and 79% after 2, 4 and 6 weeks, respectively. The incidence of perilesional irritation was, however, several times higher for the ex-tempore treated sides. At the end of the study 21 patients preferred the Dithranol-Biogram formulation, 6 the ex-tempore formulation and 6 had no preference. The results of this study suggest that this novel formulation may become an important contribution to the management of psoriasis.

Langerhans cells (LC) were studied at the light and electron microscopic levels in normal skin and in positive patch test areas after long-term healing before and after the flare-up reaction induced by oral administration of nickel. A number of reactive changes indicating increased cell activity, similar to those found in positive patch tests 72 hours after allergen application, were registered in the test areas. Thus, strong reactive changes persist in the LC system after a fulminant contact allergic dermatitis, even beyond clinical healing. Some cellular reactions, especially pronounced after oral nickel provocation, indicate that much of the LC activity takes place on a superficial level of the epidermis. Oral nickel administration induced, among other things, an intense formation of lipid-like inclusions in the LC, formerly observed only in contact allergic reaction to nickel. Goniometric analysis of the LC cytomembrane showed that the concept "spotty damage" is probably erroneous and that the LC are not targets of destruction in contact allergy. Keratinocytes adjacent to LC exhibited membrane and cytoplasmic changes indicative of interaction between these two cell types. Combined fluorescence and electron microscopic analyses of contact allergic dermatitis using long series of sections have disclosed a variety of reactive changes in, and an increased activity of, the Langerhans cell system (1, 2). In the present study Langerhans cells (LC) have been scrutinized for reactive changes after long-term healing of challenged epidermis and after oral nickel provocation causing a flare-up reaction of healed patch test areas.