The influence of a topical corticosteroid on short-contact high-dose dithranol therapy

Anthralin/dithranol in dermatology

Anthralin (1,8-dihydroxy-9anthrone, dithranol) was first synthesized as a derivative of chrysarobin, prepared from the araroba tree in Brazil over a century ago. Drawbacks to the use of anthralin include irritation and discoloration of the skin. This property of the molecule prompted workers to investigate details of its pharmacology, mode of action, and indications. The major point of this article is to highlight and revisit these aspects for pertinent future use. Therefore, it is worthwhile to consider that the drug is relatively innocuous, yet effective, and is devoid of any systemic side effects in contrast to a wide variety of systemic and topical therapies available for psoriasis and other dermatoses.

Combinations of classical time-honoured topicals in plaque psoriasis: a systematic review

BACKGROUND

Despite the availability of newer topical treatments, classical topical treatments for chronic plaque psoriasis still have an important position for selected patient populations. The vast majority of patients are treated with a combination of topicals. The question arises: what is the evidence behind these approaches?

OBJECTIVES

To systematically review all available literature on efficacy and safety of combinations of classical topical treatments in chronic plaque psoriasis, including all combinations with dithranol, coal tar and penetration enhancers, and ultimately, to propose recommendations for combination treatment.

METHODS

Standardized literature searches in PubMed, EMBASE and the Cochrane Controlled Clinical Trial Register, and allocation of the degree of evidence was carried out.

RESULTS

In total 2918 publications on topical combination therapy were revealed, of which 48 articles on combinations of classical treatments. In this article, the results concerning the 19 included publications are stated. The majority of combination regimens is at least as effective as monotherapies, and is generally well tolerated.

CONCLUSIONS

Methods of classical treatments are not standardized and different protocols in different treatment settings are used. Therefore the interpretation of study results cannot be generalized. Most evidence was found to recommend the use of a combination regimen of topical corticosteroids and salicylic acid, above monotherapy with either component. Also, the combinations of dithranol with superpotent corticosteroids or with coal tar may be preferred above both monotherapies. In case first-line treatments and systemic therapies are not effective or contraindicated, combinations of classical topicals may provide an important opportunity.

Trans-synaptic regulation of calmodulin gene expression after experimentally induced orofacial inflammation and subsequent corticosteroid treatment in the principal sensory and motor trigeminal nuclei of the rat

The cutaneous and mucosal surfaces in the infraorbital region around the whisker pad are innervated by the maxillary division of the afferent fibers of the trigeminal nerve, while certain ganglion cells project to the principal sensory trigeminal nucleus (Pr5). In turn, some of the neurons in the Pr5 project to the motor trigeminal nucleus (Mo5), whose neurons do not innervate the infraorbital skin. We analyzed the calmodulin (CaM) gene expression in these nuclei after dithranol-induced inflammation and subsequent treatment with corticosteroid in the infraorbital skin. CaM gene-specific mRNA populations were detected through quantitative image analysis of the distribution of CaM gene-specific riboprobes in brain stem cryostat sections of control rats and rats chronically treated with dithranol, corticosteroid or both. These nuclei displayed a differentially altered CaM gene expression in response to the treatments. While the CaM I and II mRNA contents were increased, the CaM III transcripts remained unaltered after chronic dithranol treatment in the Mo5. In the Pr5, however, the CaM mRNA contents were either unchanged (CaM I and III) or increased (CaM II). Subsequent corticosteroid treatment reversed the stimulatory effects of dithranol on the expression of all the CaM genes in the Mo5, but was without significant effects on the CaM I and II genes, or even increased the CaM III mRNA contents in the Pr5. Corticosteroid treatment alone was either ineffective or decreased the levels of CaM mRNAs in these nuclei. These data suggest that peripheral noxae of dermal origin may result in a trans-synaptically acting differential regulation of the multiple CaM genes in the brain.

Dithranol abolishes UCH-L1 immunoreactivity in the nerve fibers of the rat orofacial skin

Dithranol has been used to treat psoriasis for decades. Although its beneficial effect may involve the induction of cutaneous inflammation, and inflammation often leads to damages in nerve fibers, these alterations are not well documented. Therefore, we investigated the effects of dithranol on the immunohistochemical characteristics of the cutaneous nerve fibers in the rat skin. Epidermal nerve fiber staining was achieved with ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) immunohistochemistry in the orofacial skin of control rats, rats treated with (a) dithranol for 5 days, (b) corticosteroid for 5 days following dithranol treatment for 5 days, and (c) corticosteroid for 5 days. The results revealed a complete loss of UCH-L1 immunoreactivity in the dithranol-treated animals. Topical application of corticosteroid onto the inflamed skin for 5 days reversed this effect: the UCH-L1 immunoreactivity was almost completely restored. Steroid treatment for 5 days did not change the appearance of the UCH-L1-immunoreactive nerve fibers. These findings were supported by Western blot analyses. We conclude that dithranol, incidentally similarly to psoriasis, causes inflammation and abolishes UCH-L1 immunoreactivity in the rat orofacial skin in a corticosteroid-reversible manner. This phenomenon may be due to the ability of dithranol to cause oxidative damage to the UCH-L1 protein, and to the antioxidant activity of the corticosteroids countering this effect.

The effects of topical corticosteroids and a coal tar preparation on dithranol-induced irritation in patients with psoriasis

Dithranol has been a mainstay in the treatment of psoriasis for more than 80 years. Although a safe approach, the irritation of the clinically uninvolved perilesional skin remains a major limitation of this treatment. Corticosteroids and coal tar solution have an anti-inflammatory potential. The aim of the present study was to investigate the clinical and cell-biological effects of two topical corticosteroids and a coal tar preparation on dithranol-irritated skin. During 4 consecutive days, 2% dithranol cream was applied to six uninvolved skin sites (3 cm in diameter) on the lower back of 9 patients with psoriasis. Dithranol was left on the skin for 1 h, subsequently removed with water and soap and the skin was dried with a towel. Subsequently, SITE 1 was treated with 0.05% clobetasol-17-propionate ointment (CP), SITE 2 with unguentum cetomacrogolis (vehicle 1), SITE 3 with 0.005% fluticasonpropionate ointment (FP), SITE 4 with 10% coal tar solution in lanettewax cream (CTS), SITE 5 was left untreated (control) and SITE 6 was treated with lanettewax cream (vehicle 2). Erythema, oedema and vesicle formation was scored every day. On day 5, punch biopsies were taken from the six sites. The expression of epidermal proliferation, differentiation and inflammation markers and the clinical irritation scores indicate that the application of a high potency corticosteroid (CP) is the best approach to minimise dithranol irritation, whereas CTS had virtually no effect on dithranol irritation during this 4-day experimental model.

An immunohistochemical assessment of the response of the psoriatic lesion to single and repeated applications of high-dose dithranol cream

Dithranol, although a time-honoured treatment and from the beginning of the previous century still going strong, remains an empirical treatment. There is growing evidence that the biochemical basis for the mechanism of action of dithranol at the molecular level is related to the redox activity leading to the production of active oxygen species, which include singlet oxygen, superoxide anion radical and hydroxyl radical. Some authors suggest that epidermal proliferation and/or keratinisation may be the target for dithranol, while others refer to aspects of cutaneous inflammation as crucial in the antipsoriatic effect of dithranol. The present study aims to analyse the effect of single and repeated applications of dithranol on aspects of epidermal proliferation, keratinisation and inflammation in the psoriatic plaque. The most marked effect of dithranol proved to be that on epidermal proliferation (the number of Ki-67-positive nuclei) with an early reduction already 1 day following the single application. This reduction lasted for 16 days. However, such an application induced only a modest clinical improvement. Repeated challenges, resulting in a decrease in the number of Ki-67-positive nuclei of 66%, led to a substantial clinical improvement after 12 days. Repeated challenges resulted in a significant reduction of the number of polymorphonuclear leucocytes. However, this reduction was less pronounced as compared to the effect on epidermal proliferation. It is concluded that epidermal proliferation is a sensitive marker to demonstrate an early effect of dithranol. The dynamics of the cell-biological responses suggest that intermittent applications might be a promising new approach. As dithranol does not reduce the number of T lymphocytes, it is attractive to speculate that the combination of dithranol with immunosuppressive treatments might be a very effective combination.

The response of uninvolved skin of patients with psoriasis to single and repeated applications of dithranol cream: an immunohistochemical assessment

Dithranol is one of the most effective topical treatments for patients with psoriasis. The well-known irritation is a serious limitation. In an earlier study we investigated the inflammatory response to single and repeated applications with dithranol 2% cream in skin from healthy volunteers. In the present study, we assessed the clinical and cell-biological response of single and repeated challenges with dithranol 2% cream in uninvolved skin of patients with psoriasis. A striking difference between the two studies is the late phase in the single-challenge group after 8 days, showing a longer-lasting response in the uninvolved skin compared to normal skin with respect to proliferation and inflammation markers. A controlled and synchronised irritation by dithranol might induce anti-inflammatory processes and as such constitute an antipsoriatic principle. It is attractive to speculate that in psoriasis the induction of anti-inflammatory responses is defective. Following repeated applications of dithranol, a more uniform course of proliferation, differentiation and inflammation markers was observed in the uninvolved psoriatic skin as compared to the skin of healthy volunteers. Again a defect in the induction of anti-inflammatory responses might account for this event. In view of these differences between normal skin and psoriatic uninvolved skin, it may be advisable to use the uninvolved skin of patients with psoriasis in further studies on the interference between dithranol irritancy and various anti-inflammatory agents.

Combining lesional short-contact dithranol therapy of psoriasis with a potent topical corticosteroid

BACKGROUND

Since its introduction, the effectiveness of dithranol in treating psoriasis has been unequalled by other topical treatments. Out-patient short-contact dithranol treatment is effective with regard to clinical response rate and relapse rate after 1 year. A drawback, however, is the relatively long treatment duration.

OBJECTIVES

To study a dithranol regimen combined with a potent topical corticosteroid with regard to clinical response rate, treatment duration and remission period after clearance.

METHODS

Twelve patients with stable psoriasis vulgaris participated in this study. We treated three comparable psoriasis lesions on the extremities for 39 consecutive days. The first lesion was treated daily with short-contact dithranol cream followed by clobetasol-17-propionate ointment 5 days per week. The second lesion was treated daily with short-contact dithranol cream followed by the vehicle of clobetasol-17-propionate ointment. The third lesion was treated with clobetasol-17-propionate ointment 5 days per week. The patients attended on days 1, 4, 9, 12, 15, 18, 22, 25, 32 and 39 during treatment. We assessed lesional severity scores at each visit and registered the baseline area at the first visit. During the follow up at weeks 2, 4, 6, 10, 14, 19 and 23 we assessed lesional sum scores. We also estimated the area involved in recurrence of the lesion as a percentage of the baseline area. The overall differences between the three treatment curves for the treatment period and follow-up period separately were tested with a likelihood ratio test.

RESULTS

Differences between the curves of the sum scores during treatment (P < 0.001) were mainly due to the different time-course of dithranol monotherapy, which showed a slower decrease in sum score. Differences between the linear trends of the sum score (P < 0.001) and the area score P < 0.001) during follow up were due to a different time-course of the combination therapy, which started lower and increased more slowly, suggesting a slower relapse rate with combination therapy. When comparing the follow-up data, it must be kept in mind that the three treatments showed an overall significantly different sum and area score at the start of follow up.

CONCLUSIONS

Intermittent addition of clobetasol-17-propionate ointment enhanced the antipsoriatic efficacy of short-contact, high-dose dithranol therapy in terms of clearing capacity and treatment duration, without shortening remission duration.