Is dermatologic usage of coal tar carcinogenic? A review of the literature

Management of psoriasis with nutraceuticals: An update

Psoriasis is a chronic skin disorder that speeds up the life cycle of skin cells, typically on the surface of the skin. Additional skin cells form thick scales and red fixes which are awfully itchy and sometimes painful. Although there are many therapeutic systems available to get symptomatic relief, unfortunately replete cure for psoriasis is not yet reported. Moreover, poor treatment outcomes as well as high toxicity profile of drugs makes these therapies more inconvenient to treat psoriasis. In search of alternative and complementary therapy for this disease, the focus has been shifted to nutraceuticals, few of them were reported since ages. It includes vitamins, herbal extracts, phytochemicals and dietary supplements. In this review, the attempt has been made to highlight key nutraceuticals for better management of psoriasis. Supplementation of appropriate nutraceutical may improve the quality of patient's life and have positive impact on overall state of disease.

Canadian hand dermatitis management guidelines

BACKGROUND

Hand dermatitis (HD) is one of the most common skin conditions; however, it is not a homogeneous disease entity. The severity of HD may range from very mild cases to severe chronic forms, which may result in prolonged disability and, occasionally, refractory HD. Chronic hand dermatitis (CHD) is associated with a high health- economic burden and significant loss of quality of life.

OBJECTIVE

Although numerous treatment options are available, the management of CHD is often difficult and unsatisfactory. There is a paucity of well-designed, randomized, controlled clinical trials in support of the efficacy of established treatment modalities.

CONCLUSION

These guidelines cover the epidemiology, burden, quality of life, etiology, diagnosis, classification, and prevention of HD and provide guidance on management using an approach that is as evidence based as possible.

Coal tar in dermatology

Coal tar is one of the oldest treatments for psoriasis and eczema. It has anti-inflammatory, antibacterial, antipruritic and antimitotic effects. The short-term side effects are folliculitis, irritation and contact allergy. Coal tar contains carcinogens. The carcinogenicity of coal tar has been shown in animal studies and studies in occupational settings. There is no clear evidence of an increased risk of skin tumors or internal tumors. Until now, most studies have been fairly small and they did not investigate the risk of coal tar alone, but the risk of coal tar combined with other therapies. New, well-designed, epidemiological studies are necessary to assess the risk of skin tumors and other malignancies after dermatological use of coal tar.

Management of childhood psoriasis

Treating children with psoriasis represents one of the most rewarding yet constantly challenging endeavors in dermatology. These patients require time, energy, enthusiasm, empathy, and current, comprehensive knowledge of the unique clinical presentations in children and available therapies, including clinical action spectrum, mechanism of action, potential toxicity, and monitoring. Longitudinal trials examining the epidemiology and natural history of psoriasis, as well as the safety and efficacy of current and emerging treatments, are desperately needed in the pediatric population. Partner with the patient, family, and other multidisciplinary providers to form an educational and therapeutic alliance. Early in the course of disease, schedule frequent visits for reinforcement of the therapeutic plan, education, clinical and treatment monitoring, and support. As the disease and the patient's physical, psychosocial and emotional level of functioning evolve, so too will the requirement for follow-up and monitoring. Patient advocacy and education groups, such as the National Psoriasis Foundation (www.psoriasis.org; 800-723-9166) are excellent resources and can serve as an extension of your comprehensive care.

Psoríase na infância e na adolescência

A psoríase é doença inflamatória crônica, imunologicamente mediada, recorrente e de caráter universal. Aproximadamente um terço dos adultos acometidos refere início da doença antes dos 16 anos de idade. Quanto mais precoce, mais grave tende a ser a evolução do quadro. Em crianças, as lesões podem ser fisicamente desfigurantes, causando prejuízos psicológicos e evidente comprometimento da qualidade de vida. As medicações sistêmicas utilizadas na psoríase, bem como a fototerapia, têm indicação limitada na infância, devido aos efeitos cumulativos das drogas, à baixa aceitação e ao risco de teratogenicidade. Nesta seção, discutiremos as principais manifestações clínicas da psoríase na infância e na adolescência, bem como os diagnósticos diferenciais, opções terapêuticas e prognóstico.

Final safety assessment of Coal Tar as used in cosmetics

Coal Tar is a semisolid by-product obtained in the destructive distillation of bituminous coal, which functions in cosmetic products as a cosmetic biocide and denaturant--antidandruff agent is also listed as a function, but this is considered an over-the-counter (OTC) drug use. Coal Tar is a nearly black, viscous liquid, heavier than water, with a naphthalene-like odor and a sharp burning taste, produced in cooking ovens as a by-product in the manufacture of coke. Crude Coal Tar is composed of 48% hydrocarbons, 42% carbon, and 10% water. In 2002, Coal Tar was reported to the Food and Drug Administration (FDA) to be used in four formulations, all of which appear to be OTC drug products. Coal Tar is monographed by the FDA as Category I (safe and effective) OTC drug ingredient for use in the treatment of dandruff, seborrhoea, and psoriasis. Coal Tar is absorbed through the skin of animals and humans and is systemically distributed. In short-term studies, mice fed a diet containing Coal Tar found it unpalatable, but no adverse effects were reported other than weight loss; rats injected with Coal Tar experienced malaise in one study and decreased water intake and increased liver weights in another; rabbits injected with Coal Tar residue experienced eating avoidance, respiratory difficulty, sneezing, and weight loss. In a subchronic neurotoxicity study using mice, a mixture of phenols, cresols, and xylenols at concentrations approximately equal to those expected in Coal Tar extracts produced regionally selective effects, with a rank order of corpus striatum > cerebellum > cerebral cortex. Coal Tar applied to the backs of guinea pigs increases epidermal thickness. Painting female rabbits with tar decreases the absolute and relative weights of the ovaries and decreased the number of interstitial cells in the ovary. Four therapeutic Coal Tar preparations used in the treatment of psoriasis were mutagenic in the Ames assay. Urine and blood from patients treated with Coal Tar were genotoxic in bacterial assays. Coal Tar was genotoxic in a mammalian genotoxicity assay and induced DNA adducts in various tissue types. Chronic exposure of mice to Coal Tar significantly decreased survival and liver neoplasms were seen in a significant dose-related trend; in other studies using mice lung tumors and perianal skin cancers were found. Coal Tar was comedogenic in three small clinical studies. Folliculitis is associated with the prolonged use of some tars. Several published reports describe cases of contact sensitivity to Coal Tar. Polycyclic aromatic hydrocarbons, which make up Coal Tar, are photosensitizers and cause phototoxicity by an oxygen-dependent mechanism. A retrospective study of the reproductive toxicity of Coal Tar in humans compared exposed women to controls and found little difference in spontaneous abortion and congenital disorders. Cancer epidemiology studies of patients who have received Coal Tar therapy of one form or other have failed to link treatment with an increase in the risk of cancer. Although the Cosmetic Ingredient Review (CIR) Expert Panel believes that Coal Tar use as an antidandruff ingredient in OTC drug preparations is adequately addressed by the FDA regulations, the Panel also believes that the appropriate concentration of use of Coal Tar in cosmetic formulations should be that level that does not have a biological effect in the user. Additional data needed to make a safety assessment include product types in which Coal Tar is used (other than as an OTC drug ingredient), use concentrations, and the maximum concentration that does not induce a biological effect in users.

Steroids versus other immune modulators in the management of allergic dermatoses

PURPOSE OF REVIEW

The classic role of topical and systemic corticosteroids for allergic dermatoses is discussed, with special attention to the impact on the current clinical treatment paradigm by newer systemic and topical therapies. These products are reviewed and recommendations presented on how to effectively assimilate them into clinical practice.

RECENT FINDINGS

Current knowledge about the etiopathogenesis of atopic dermatitis has resulted in drug development focused on agents with less toxicity than current topical and systemic corticosteroids. Some agents with ceramide/cholesterol/acid combinations demonstrate efficacy in restoring the dysfunctional skin barrier of atopic patients. Concerns resulting from the recent Federal Drug Administration announcement regarding a theoretical risk of cancer associated with topical calcineurin inhibitors are also addressed. Novel therapeutic entities are presented.

SUMMARY

Patients seeking relief from atopic dermatitis have historically had few really effective and safe therapeutic options. Topical calcineurin inhibitors represent an exciting new therapy for atopic dermatitis without the side-effect profile associated with topical corticosteroids. Nonsteroidal formulations incorporating glycyrrhetinic acid/telmesteine/Vitis vinifera extract and palmitoylethanolamide as 'active' ingredients recently entered the market, stressing antipruritic, antiinflammatory, and skin barrier repair. This confabulates against previously designed topical therapy paradigms. These new products may be used as monotherapy or alternatives to steroid agents.

Therapeutic options in the treatment of psoriasis and atopic dermatitis

A variety of therapeutic options are available to treat psoriasis and atopic dermatitis (AD). Local agents typically are used to treat localized and milder forms of disease, whereas phototherapy and systemic agents are used for more generalized and severe disease. Various combinations and sequences of topical or systemic therapies, or both, have been utilized in the treatment of psoriasis and, less frequently, of AD. Conventional systemic therapies for psoriasis, such as corticosteroids, oral calcineurin inhibitors, antimetabolites, and retinoids, are limited by their propensity to cause serious side effects. More recently, a number of immunobiologic agents, such as monoclonal antibodies, recombinant cytokines, and fusion proteins, have been approved by the Food and Drug Administration or are undergoing development as systemic antipsoriatic treatments. In many of these categories, a number of exciting new therapies are in development that may augment the existing armamentarium available to clinicians for the treatment of inflammatory skin diseases.

Wavelength dependent responses of primary human keratinocytes to combined treatment with benzo[a]pyrene and UV light

The major risk factor for skin cancer is exposure to UV radiation from sunlight, but other environmental exposures may also play a role in combination with UV. We have studied the effects of combined exposure of primary human skin cells in vitro to UVA, UVB or UVC with benzo[a] pyrene (BaP), an environmental carcinogen. Normal human keratinocytes were exposed to 5 microM BaP for 24 h followed by either 1 kJ/m(2) UVA, 100 J/m(2) UVB or 10 J/m(2) UVC. Only BaP + UVA caused increased cell death. BaP or UVA alone did not induce significant DNA damage as measured by comet assay but combined exposure induced 35.1 +/- 6.0% tail DNA, compared with 9.7 +/- 1.3% tail DNA in control cells. After including the Fapy-DNA glycosylase enzyme incubation step to detect oxidized purines, % tail DNA increased another 11.2 +/- 2.9%. Combined exposure of BaP and UVB did not increase damage in the comet assay without Fapy-DNA glycosylase, but in the presence of this enzyme % tail DNA increased by 9.3 +/- 2.2%. BaP + UVB also abrogated the UVB-induced cell cycle G2 arrest. BaP + UVC had no effect on the keratinocytes compared with each treatment alone. These results show a wavelength-dependent difference in the effects of combined exposure on normal human keratinocytes. Both UVA and UVB damage can be enhanced by BaP pre-exposure, although the effects seen with UVA were greater. These findings are important to understanding the role of UVA and UVB in skin carcinogenesis and may have implications for recommended sun exposure limits, especially in polluted areas.

Photochemical genotoxicity: principles and test methods. Report of a GUM task force

In recent years, assessing the photogenotoxic potential of a compound became an issue for certain drugs and cosmetical products. Therefore, existing methods performed according to international guidelines (e.g. OECD guidelines) were adapted to the use of concurrent UV-visible (UV-Vis) light irradiation for the assessment of photomutagenicity/photogenotoxicity. In this review, photobiological bases of the processes occurring in the cell after irradiation with UV- and/or visible (vis)-light as well as a compilation of testing methods is presented. Methods comprise cell free investigations on naked DNA and in vitro methods, such as the photo-Ames test, the photo-HPRT/photo-mouse lymphoma assay (MLA), the photo-micronucleus test (MNT), the photo-chromosomal aberration test (CA) and the photo-Comet assay. A compilation of the currently available international literature of compounds tested on photogenotoxicity is given for each method. The state of the art of photogenotoxicity testing as well as the rational for testing are outlined in relation to the recommendations reached in expert working groups at different international meetings and to regulatory guidance papers. Finally, photogenotoxicity testing as predictor of photocarcinogenicity and in the light of risk assessment is discussed.

[Topical treatment of psoriasis: a systematic update]

Classical topical treatment regimens in psoriasis including dithranol and corticosteroids are widely used and have been supplemented in recent years by topical vitamin D preparations, by vitamin D analogues and topical retinoids. The combination of these preparations with each other, with UV light or with systemic drugs often lead to improved effectiveness and tolerability when compared with the respective monotherapy. In private offices, the combination of calcipotriol with various corticosteroids is very commonly prescribed for patients with mild to moderate psoriasis. This combination can be sequentially applied twice daily or--in a newly introduced fixed preparation--once daily. In severe psoriasis requiring systemic treatment a concomitant effective topical treatment regimen can greatly improve the overall longtime management in affected patients.

A strong genotoxic effect in mouse skin of a single painting of coal tar in hairless mice and in MutaMouse

The dorsal skin of C3H/Tif/hr hairless mice was painted with coal tar, pharmacological grade. Epidermal cells and hepatocytes were isolated after 4, 24, 48 and 96 h and DNA strand breaks were determined as tail moment by the alkaline comet assay. The tail moment of epidermal cells was significantly greater at the time points 4, 24, 48 and 96 h after exposure compared to the controls, with the most DNA strand breaks at 24 h. The DNA strand breaks in epidermal cells increased linearly with the dose of coal tar. In hepatocytes, no difference in DNA strand breaks was found between exposed animals and controls. DNA adducts were determined by the 32P-postlabeling assay. For epidermal cells, the mean DNA adduct level was 12-fold greater in coal tar painted mice after 24 h than in controls. Again, a linear dose/response relationship was seen 24 h after painting. For liver DNA, the mean DNA adduct level was 3-fold greater than for controls. The mutation frequency in epidermal and liver cells was examined in lambdalacZ transgenic mice (MutaMouse). Thirty-two days after painting, the mutation frequency in epidermal cells was 16-fold greater in coal tar treated mice compared to controls. No effect was detected in hepatocytes. We found that a single painting of coal tar resulted in strong genotoxic effects in the murine epidermis, evidenced by induction of DNA strand breaks and DNA adducts in hairless mice and lambdalacZ mutations in the MutaMouse. This demonstrates that it is possible to detect genotoxic effects of mixtures with high sensitivity in mouse skin by these end-points.

Phototoxicity and photoallergy

Photosensitivity may be phototoxic or photoallergic. Phototoxicity is much more common. There are 2 types of phototoxicity: photodynamic, which requires oxygen, and nonphotodynamic, which does not. Reactions induced by porphyrin molecules, coal tar derivatives, and many drugs are photodynamic. The reaction induced by psoralens, for the most part, is nonphotodynamic. Acute phototoxic reactions are characterized by erythema and edema followed by hyperpigmentation. Long-term ultraviolet phototoxicity results in chronic sun damage and skin cancer formation. Also, certain chemicals such as psoralen molecules and coal tar are photocarcinogenic. Phototoxic reactions to certain drugs produce unusual clinical patterns, that is lichenoid eruptions, dyschromia, photo-onycholysis, and pseudoporphyria. Photoallergy is an uncommon acquired altered reactivity dependent on an immediate antibody or a delayed cell mediated reaction. Solar urticaria is an example of the former, whereas photoallergy to exogenous chemicals is an example of the latter. Photoallergy to systemic drugs does occur but is difficult to characterize. The action spectrum for photoreactions to exogenous agents usually at least includes the ultraviolet A rays for both phototoxicity and photoallergy.

Coal tar therapy. Is it carcinogenic?

Epidemiological studies indicate that occupational exposure to coal tar may lead to an increased risk of lung, scrotum and skin cancer. Furthermore, studies with laboratory rodents show carcinogenicity of coal tar after dermal application. This effect may be attributable to polycyclic aromatic hydrocarbons (PAH), which are ubiquitous coal tar constituents. Absorbed PAH can be metabolised to reactive derivatives that bind to DNA. These PAH-DNA binding products are thought to be involved in PAH-induced carcinogenesis. However, no clearly increased skin cancer incidences have been reported in psoriasis patients who have been exposed to therapeutically high doses of coal tar. To determine whether patients treated with coal tar actually have an altered risk of cutaneous malignancies, we suggest that further controlled studies and experiments are necessary. Future research should also focus on the possibility of increased risks of developing internal malignancies.

Premalignant keratinocytic neoplasms

Premalignant keratinocytic keratoses are common, especially in pale-complected persons in whom they appear most often as an actinic keratosis. Although the actinic keratosis has a very low malignant potential, arsenic, tar, thermal, scar, reactional, and radiation keratoses may be more clinically aggressive. This article discusses these premalignant keratinocytic neoplasms.