[Antipruritic effects of pimecrolimus and tacrolimus]

Scalp Pruritus: Review of the Pathogenesis, Diagnosis, and Management

Scalp pruritus is a frequent problem encountered in dermatological practice. This disorder is caused by various underlying diseases and is a diagnostic and therapeutic challenge. Scalp pruritus may be localized to the scalp or extended to other body areas. It is sometimes not only associated with skin diseases or specific skin changes, but also associated with lesions secondary to rubbing or scratching. Moreover, scalp pruritus may be difficult to diagnose and manage and may have a great impact on the quality of life of patients. It can be classified as dermatologic, neuropathic, systemic, and psychogenic scalp pruritus based on the potential underlying disease. A thorough evaluation of patients presenting with scalp pruritus is important. Taking history and performing physical examination and further investigations are essential for diagnosis. Therapeutic strategy comprises removal of the aggravating factors and appropriate treatment of the underlying condition. All treatments should be performed considering an individual approach. This review article focuses on the understanding of the pathophysiology and the diagnostic and therapeutic management of scalp pruritus.

A systematic review of evidence-based treatments for prurigo nodularis

Prurigo nodularis is a chronic dermatologic condition involving the development of multiple cutaneous nodules in the setting of intractable pruritus. Given emerging treatment options for this difficult-to-treat condition, a current review of therapeutics is needed. A systematic review was performed for clinical studies investigating prurigo nodularis treatment published from 1990 to present including ≥5 subjects. A total of 35 articles were assigned a level of evidence according to the Oxford Center for Evidence-based Medicine. All 5 studies investigating topical agents, including corticosteroids, calcineurin inhibitors, calcipotriol, and capsaicin, conveyed some beneficial effect with level of evidence 2b or higher. Six of 8 reports investigating photo- and photochemotherapy achieved levels of evidence 2b or greater and showed good partial response rates. Thalidomide was studied by 6 reports providing evidence of good symptom response, only 2 of which were rated level 2b or greater. Cyclosporine and methotrexate have demonstrated benefit in 4 combined studies, albeit with level 4 evidence. Pregabalin, amitriptyline, paroxetine, fluvoxamine, and neurokinin-1 receptor antagonists have demonstrated promising evidence in 5 level 2b studies. Higher-powered studies and additional randomized controlled trials are needed for the evaluation of safe and efficacious systemic treatment options for prurigo nodularis.

Current and Emerging Therapies for Itch Management in Psoriasis

Pruritus is a common and significant symptom among patients with psoriasis. Pruritus is often present beyond the borders of psoriatic plaques, and frequently affects the scalp and genital regions. Psoriatic itch may be severe and can profoundly affect quality of life and sleep, even in the context of mild-to-moderate disease. These features often make the treatment of psoriatic pruritus challenging. However, there are a variety of effective topical and systemic treatment modalities available to address this symptom. While there remains a need for treatments that specifically target psoriatic itch, newly licensed therapies including secukinumab, ixekizumab and apremilast have been shown to rapidly and effectively mediate itch reduction.

Assessing the itching intensity using visual analogue scales in atopic dermatitis patients against the background of a therapy with calcineurin inhibitors

Goal. To assess the effect of topical treatment of atopic dermatitis patients with the 0.1% tacrolimus ointment on the itching intensity and skin expression level of growth factor proteins affecting the intensity of cutaneous innervation. Materials and methods. Fifteen patients suffering from atopic dermatitis underwent treatment with the 0.1% tacrolimus ointment. The SCORAD index was calculated to assess the severity of clinical manifestations. The itching intensity was assessed using a visual analogue scale. The skin expression of nerve growth factors, amphiregulin, semaphorin 3A and PGP9.5 protein (a nerve fiber marker) was assessed by the indirect immunofluorescence method. Results. An increased expression of the nerve growth factor and reduced semaphorin 3A expression levels were noted in the patients’ epidermis; there was an increase in the quantity, mean length and fluorescence intensity of PGP9.5+ nerve fibers. As a result of the treatment, the disease severity and itching intensity were reduced, the nerve growth factor expression level was reduced while semaphorin 3A expression level increased in the epidermis, and the mean length and fluorescence intensity of PGP9.5+ nerve fibers was also reduced. A positive correlation among the itching intensity and nerve growth factor expression level, quantity and mean length of PGP9.5+ nerve fibers in the epidermis was revealed, and negative correlation between the itching intensity and semaphorin 3A expression level in the epidermis was established. Conclusion. Topical treatment with the 0.1% Tacrolimus ointment reduces the itching intensity in atopic dermatitis patients, which is related to the therapy-mediated reduction in the epidermis innervation level, decreased expression of epidermal nerve growth factor and increased semaphorin 3A expression level.

Evaluation of the antipruritic effects of topical pimecrolimus in non-atopic prurigo nodularis: results of a randomized, hydrocortisone-controlled, double-blind phase II trial

BACKGROUND

In the treatment of atopic dermatitis, pimecrolimus has high antipruritic effects.

OBJECTIVE

To investigate the efficacy of 1% pimecrolimus cream in comparison to 1% hydrocortisone cream in non-atopic prurigo nodularis (PN).

METHODS

A randomized, controlled, double-blind study with intraindividual randomization was done in 30 patients (17 females, 13 males; mean age 58.5 years) with PN.

RESULTS

Pruritus intensity decreased significantly (p < 0.001) on both treated sides as early as after 10 days of treatment; scratch lesions improved (p < 0.001). Quality of life as assessed by the Dermatology Life Quality Index improved significantly. However, a significant advantage of pimecrolimus over hydrocortisone was not found.

CONCLUSION

The results suggest that the non-steroid pimecrolimus is an effective alternative for PN treatment.

Red ginseng inhibits scratching behavior associated with atopic dermatitis in experimental animal models

Pruritus is a severe symptom that is difficult to treat in atopic dermatitis patients. Red ginseng (RG), a natural medicine, has various biological activities such as anti-inflammatory effects. In this study, we examined the efficacy of RG extract (RGE) and its mechanism on experimental atopic dermatitis in mice. The effects of RGE on vascular permeability and itching were first evaluated. Histamine-induced permeability and itching were significantly inhibited by embrocation with RGE as well as diphenhydramine, an antihistamine drug. Next, we assessed the therapeutic effect of topical RGE in a mouse model of atopic dermatitis. Dermatitis was induced by repeated application of 2,4-dinitrofluorobenzene (DNFB) acetone solution to the mouse ear. The effects of tacrolimus (a calcineurin blocker), dexamethasone (a corticosteroid), and RGE on dermatitis and associated scratching behavior were compared. Repeated DNFB application caused frequent scratching behaviors and ear swelling. Topical treatment with tacrolimus, dexamethasone, and RGE for 8 days before the final challenge with DNFB significantly inhibited ear swelling. Tacrolimus and RGE significantly inhibited scratching behavior, whereas dexamethasone failed to do so. DNFB-induced nerve growth factor expression and nerve fiber extension were significantly attenuated by tacrolimus and RGE, but not by dexamethasone. RGE may have the potential for treatment of atopic dermatitis.

Treatment of pruritic diseases with topical calcineurin inhibitors

The introduction of topical calcineurin inhibitors resulted in a significant improvement in the treatment of atopic dermatitis. In addition, rapid amelioration of pruritus could be observed. In case reports, other pruritic dermatoses such as chronic irritative hand dermatitis, rosacea, graft-versus-host-disease, and lichen sclerosus were also treated successfully with pimecrolimus and tacrolimus. Twenty patients were treated with tacrolimus and pimecrolimus in a surveillance study to evaluate efficacy in pruritus and prurigo. Eighteen of 20 patients responded to therapy. Best results were obtained in localized and generalized pruritus while in prurigo nodularis only a subgroup of patients showed an improvement of pruritus. Further controlled studies are necessary to confirm these results.

Chronic pruritus: clinics and treatment

Chronic pruritus, one of the main symptoms in dermatology, is often intractable and has a high impact on patient's quality of life. Beyond dermatologic disorders, chronic pruritus is associated with systemic, neurologic as well as psychologic diseases. The pathogenesis of acute and chronic (>6 weeks duration) pruritus is complex and involves in the skin a network of resident (e.g., sensory neurons) and transient inflammatory cells (e.g., lymphocytes). In the skin, several classes of histamine-sensitive or histamine-insensitve C-fibers are involved in itch transmission. Specific receptors have been discovered on cutaneous and spinal neurons to be exclusively involved in the processing of pruritic signals. Chronic pruritus is notoriously difficult to treat. Newer insights into the underlying pathogenesis of pruritus have enabled novel treatment approaches that target the pruritus-specific pathophysiological mechanism. For example, neurokinin-1 antagonists have been found to relieve chronic pruritus.

Pathophysiology and therapy of pruritus in allergic and atopic diseases

Pruritus (itch) is a major characteristic and one of the most debilitating symptoms in allergic and atopic diseases and the diagnostic hallmark of atopic dermatitis. Pruritus is regularly defined as an unpleasant sensation provoking the desire to scratch. Although we achieved rather good knowledge about certain inducers of itch such as neuropeptides, amines, mu-opioids, cytokines and proteases, for example, less is known about the pathophysiological specifities among the different diseases, and the therapeutic consequences which may derive thereoff. This review dissects the role of mediators, receptors and itch inhibitors on peripheral nerve endings, dorsal root ganglia, the spinal cord and the CNS leading to the amplification or - vice versa - suppression of pruritus. As the treatment of pruritus in allergic and atopic skin disease is still not satisfactory, knowing these pathways and mechanisms may lead to novel therapeutic approaches against this frequently encountered skin symptom.

Depletion of substance P, a mechanism for inhibition of mouse scratching behavior by tacrolimus

Itching is the most important problem in atopic dermatitis and tacrolimus has been suggested to attenuate the itching by topical application. However, the anti-itch mechanism of tacrolimus has not been well elucidated. In the present study, an allergic dermatitis accompanied by frequent scratching behaviors was induced by repeated paintings with 2,4-dinitrofluorobenzene (DNFB) acetone solution onto the mouse ear and the effects of tacrolimus and dexamethasone on the dermatitis and associated scratching behavior were comparatively examined. Repeated DNFB paintings caused a typical dermatitis accompanied by elevated serum immunoglobulin E (IgE) and frequent scratching behaviors. Both tacrolimus and dexamethasone given topically for 10 days before the final challenge significantly inhibited the ear swelling and reduced the expression of interferon-gamma mRNA. Dexamethasone inhibited the accumulation of eosinophils completely, although tacrolimus did not. Both drugs did not affect the elevation of serum IgE levels. Tacrolimus significantly inhibited the scratching behavior, whereas dexamethasone failed to affect it. Repeated DNFB challenge depleted substance P in the dermis. Treatment with tacrolimus before the final challenge completely inhibited the recovery of substance P content, whereas dexamethasone facilitated the recovery. DNFB-induced ear swelling and scratching behavior were significantly inhibited by FK888, a tachykinin NK(1) receptor antagonist. Therefore, substance P seems to participate in the induction of ear swelling and scratching behavior upon final challenge with DNFB, and depletion of substance P by tacrolimus in the dermis contributes to its inhibition of ear swelling and scratching behavior at least in part.

Efficacy of topical pimecrolimus in the treatment of chronic vulvar pruritus: A prospective case series – a non‐controlled, open‐label study

BACKGROUND

Chronic vulvar pruritus has been a most distressing physical and sociologic disorder for many patients, as well as for their physicians. Potent topical steroids are the conventional therapy for this distressing condition. Side effects or steroid resistance can be encountered. A second-line therapy is required.

OBJECTIVES

A single-centre, non-controlled, open-label study was designed to assess the efficacy of topical pimecrolimus in the treatment of chronic vulvar pruritus.

METHODS

Fifteen married adult women with symptoms of vulvar pruritus > or =4 months were included in the study. The patients did not have any relief with topical steroids. There were no objective physical findings. Topical pimecrolimus 1% cream (Elidel cream, Novartis) was applied twice daily to the vulvar region. Patients were followed up 4 weeks later. After the trial was stopped, the patients remained in regular review for 3 months.

RESULTS

Thirteen patients tolerated pimecrolimus. They showed a clinical response within 2-4 weeks. Ten patients showed a complete response, three showed a partial response. After the trial had stopped, the patients with complete response were followed-up by telephone for another 3 months, and were found to be in remission.

CONCLUSIONS

We found that topical pimecrolimus provides relief for chronic vulvar pruritus. Pimecrolimus can be chosen as the second-line therapy in patients with vulvar pruritus.

[Rational symptomatic therapy for chronic pruritus]

Chronic pruritus is a difficult-to-treat problem which accompanies many dermatologic and systemic diseases. Frequently, therapy is ineffective and prolongs the pruritus. Thus significant costs arise for the health system, which are clearly lowered by a rational therapy concept. Extensive knowledge about both topical and systemic therapy of pruritus has been acquired in recent years. Currently, new therapeutic approaches are available, which intervene in different pruritogenic mechanisms. Substances can block the cutaneous pruritus induction (e.g. antihistamines, leukotriene antagonists, cannabinoid agonists) or mediate central effects such as the inhibition of pruritus transmission via the spinal cord (e.g. naltrexone, gabapentin) or the suppression of the cerebral itch perception (e.g. antidepressants, neuroleptics). Usually combining several therapeutic principles is necessary in order to suppress chronic pruritus with lasting effect. The most effective approach is to gradually combine therapies, always considering both the medical and financial impacts.

Neuronal Control of Skin Function: The Skin as a Neuroimmunoendocrine Organ

This review focuses on the role of the peripheral nervous system in cutaneous biology and disease. During the last few years, a modern concept of an interactive network between cutaneous nerves, the neuroendocrine axis, and the immune system has been established. We learned that neurocutaneous interactions influence a variety of physiological and pathophysiological functions, including cell growth, immunity, inflammation, pruritus, and wound healing. This interaction is mediated by primary afferent as well as autonomic nerves, which release neuromediators and activate specific receptors on many target cells in the skin. A dense network of sensory nerves releases neuropeptides, thereby modulating inflammation, cell growth, and the immune responses in the skin. Neurotrophic factors, in addition to regulating nerve growth, participate in many properties of skin function. The skin expresses a variety of neurohormone receptors coupled to heterotrimeric G proteins that are tightly involved in skin homeostasis and inflammation. This neurohormone-receptor interaction is modulated by endopeptidases, which are able to terminate neuropeptide-induced inflammatory or immune responses. Neuronal proteinase-activated receptors or transient receptor potential ion channels are recently described receptors that may have been important in regulating neurogenic inflammation, pain, and pruritus. Together, a close multidirectional interaction between neuromediators, high-affinity receptors, and regulatory proteases is critically involved to maintain tissue integrity and regulate inflammatory responses in the skin. A deeper understanding of cutaneous neuroimmunoendocrinology may help to develop new strategies for the treatment of several skin diseases.

Inhibition of scratching behavior associated with allergic dermatitis in mice by tacrolimus, but not by dexamethasone

Itching is the most important problem in many allergic and inflammatory skin diseases especially in atopic dermatitis. However, animal models for allergic dermatitis useful for the study of itching have rarely been established. We established a mouse allergic dermatitis model involving frequent scratching behavior by repeated painting with 2,4-dinitrofluorobenzene (DNFB) acetone solution onto the mouse skin, and comparatively examined the effects of tacrolimus and dexamethasone on the dermatitis and associated scratching behavior. Repeated DNFB painting caused typical dermatitis accompanied by elevated serum immunoglobulin E (IgE) and frequent scratching behavior. An apparent thickening of the epidermis and dermis, and the significant accumulation of inflammatory cells were observed. Increased interferon (IFN)-gamma mRNA expression and the induction of interleukin (IL)-4 and IL-5 mRNA expression were also observed in the skin lesion. The scratching behavior was inhibited by dibucaine and naloxone. Although tacrolimus reduced the increased expression of IFN-gamma and IL-4 mRNA, dexamethasone potently depressed that of IFN-gamma, IL-4 and IL-5 mRNA. Dexamethasone inhibited the accumulation of lymphocytes and eosinophils, although tacrolimus did not. Both drugs failed to inhibit the elevation of serum IgE levels. Tacrolimus significantly inhibited the scratching behavior that was associated with the inhibition of nerve fiber extension into the epidermis, whereas dexamethasone failed to have any effect. The mouse dermatitis model seems to be beneficial for the study of itching associated with allergic dermatitis, such as atopic dermatitis, and tacrolimus seems to exhibit an anti-itch effect through the inhibition of nerve fiber extension at least in part.

Calcineurin antagonists in vulvar lichen sclerosus

Lichen sclerosus et atrophicus is a chronic inflammatory disorder that mainly affects girls of premenarchial age and women in their fifties. Besides the anogenital region, lichen sclerosus (LS) may also affect extragenital or mucosal areas. Symptoms include soreness and pruritus, but other less common symptoms are not rare. An increased activity of fibroblasts causes increased sclerosis of the affected skin. Latest studies have identified LS as a chronic inflammatory dermatosis. Auto-antibodies against the extracellular membrane protein-1 are present in up to 80% of the patients. Moreover, in the widely accepted therapy with potent corticosteroids promising results have been presented using calcineurin antagonists in the treatment of LS. An interdisciplinary management and a continued care of patients with LS will improve the clinical manifestations and quality of life.

Wirksamkeit von Tacrolimus-0,1-%-Salbe bei Prurigoerkrankungen. Efficacy of tacrolimus 0.1 % ointment in prurigo

BACKGROUND

Potent topical corticosteroids are used the intense pruritus in prurigo diseases. Their long-term application leads to local side effects such as atrophy and telangiectasia.

PATIENTS AND METHODS

We treated 6 women (average age 64 years) with chronic prurigo with tacrolimus 0.1 % ointment (Protopic) to evaluate its efficacy in this clinical setting. Tacrolimus 0.1% ointment was applied twice a day for 4 weeks.

RESULTS

After one week, both clinical improvement and reduced pruritus were observed in all patients.

CONCLUSION

Tacrolimus 0.1% ointment represents a therapeutic option for the treatment of prurigo.

Lichen sclerosus

Lichen sclerosus et atrophicus is a chronic inflammatory disease that mainly affects women in the 5th decade. Although lichen sclerosus most often affects the anogenital region, it may occur in other cutaneous or mucosal sites. Increased fibroblast activity causes cutaneous sclerosis. Recent studies have identified lichen sclerosus as an autoantibody-mediated chronic inflammatory dermatosis. Autoantibodies against the extracellular matrix protein-1 are present in up to 80% of affected patients. In addition to the well-accepted therapy with potent corticosteroids, promising results have been obtained using calcineurin antagonists in the treatment of lichen sclerosus. Interdisciplinary management with regular monitoring can improve the clinical manifestations and quality of life.

The mode of topical immunomodulators in the immunological network of atopic dermatitis

For a long time, therapeutic strategies of atopic dermatitis (AD) have been dominated by the application of local or systemic steroids or other immunosuppressive agents, which have been limited by their potential for unwanted local or systemic side effects. Recently, the use of a new generation of topical nonsteroidal, immunomodulatory drugs has revolutionized the therapeutic options of this often recalcitrant allergic-inflammatory skin disease. Research work has focused on the identification of the exact mode of action and the immune specificities of the so-called 'topical immunomodulators' (TIMs) such as tacrolimus and pimecrolimus in AD. In addition to the previous findings about the mode of action of TIMs on T cells, other target cells of TIMs such as keratinocytes, mast cells, eosinophils and dendritic cells have been identified recently as potential therapeutic targets. In this overview, we provide a research update about the anti-inflammatory and anti-allergic properties of TIMs on effector cells of AD that may be involved in the complex pathophysiology of AD.

The immunosuppressant FK506 activates capsaicin- and bradykinin-sensitive DRG neurons and cutaneous C-fibers

Immunosuppressant drug FK506, which is widely used for the treatment of atopic dermatitis, has multiple actions on the nervous system. In order to elucidate the mechanisms underlying transient burning sensation elicited by topical application of FK506 to the skin of atopic patients, we investigated if FK506 directly activates sensory neurons and fibers, or not. Ca(2+) imaging study on cultured DRG neurons of rats revealed that application of FK506 raised intracellular Ca(2+) levels in a subpopulation of small DRG neurons (3.1% of DRG neurons responsive to high K(+) solution). When DRGs from inflamed rats were used, the incidence increased to 7.4%. FK506 sensitive neurons also responded to a subsequent application of capsaicin (89.5% in normal, and 100% in inflamed rats) and bradykinin (31.6% in normal, and 80.9% in inflamed rats). Single fiber recordings in the skin-nerve preparation confirmed the results of cell culture study, showing that application of FK506 enhanced neuronal discharges of single C-fibers that are responsive to heat and bradykinin. These findings, taken together, indicate that FK506 application on inflamed skin may activate nociceptive C-fibers, which bear bradykinin receptors and capsaicin-sensitive heat transducer of TRP family, TRPV1.

Pimecrolimus - an anti-inflammatory drug targeting the skin

Pimecrolimus is the most recent member of calcineurin inhibitors available for the therapy for inflammatory skin diseases. It targets T-cells and mast cells and inhibits the production and release of cytokines and other inflammatory mediators, as well as the expression of signals essential for the activation of inflammatory T-lymphocytes. Pimecrolimus has a cell-selective mode of action. In contrast to corticosteroids, it does not affect, e.g., Langerhans'cells/dendritic cells (LC/DC), as demonstrated in vitro with human monocyte-derived DC and in vivo with epidermal LC in mice, nor human primary fibroblasts. As shown in vitro with human skin and by comparison of clinical pharmacokinetic data from patients with atopic dermatitis, pimecrolimus permeates less through skin than tacrolimus and much less than corticosteroids. It, thus, has a lower potential for transcutaneous resorption after topical administration, resulting in a lower risk of systemic effects. Pimecrolimus has high anti-inflammatory activity in animal models of skin inflammation, including a model reflecting neurogenic inflammation, but a more favourable balance of anti-inflammatory vs. immunosuppressive activity than tacrolimus. Pimecrolimus does not affect sensitization in a murine model of allergic contact dermatitis and has a lower potency in various models of immunosuppression after systemic administration, compared to tacrolimus. In conclusion, the results of preclinical studies show that pimecrolimus has a selective pharmacological profile, suited for effective and safe treatment for inflammatory skin diseases.

Pimecrolimus 1% cream for anogenital lichen sclerosus in childhood

Background

Lichen sclerosus is a chronic inflammatory disease with a predilection of the anogenital region. Because of the potential side effects of repeated local application of potent glucocorticosteroids, equally-effective, safer therapeutic options are required, especially in the treatment of children.

Case presentations

We report on the efficacy of twice-daily application of pimecrolimus 1% cream in four prepubertal girls (range of age: 4 to 9 years) who suffered from anogenital lichen sclerosus. After three to four-month treatment, all patients had almost complete clinical remission including relief from itch, pain and inflammation. Only minor improvement was observed for the white sclerotic lesions. No significant side effects have been observed.

Conclusions

Topical pimecrolimus appears to be an effective and safe treatment for children with anogenital lichen sclerosus. The clinical benefits observed in the four patient presented particularly include relief of pruritus, pain and inflammation. Vehicle-controlled studies on a larger number of patients are now warranted to substantiate our promising findings, and to investigate long-term efficacy and safety of topical pimecrolimus in anogenital lichen sclerosus.

[Pruritus in childhood. A diagnostic and therapeutic challenge]

From the clinician's point of view, pruritus in children is quite frequent. It mainly occurs along with dermatoses but rarely with systemic diseases such as renal and liver failure or with genetic disorders. Mostly, it appears in the setting of atopic dermatitis (AD). Other frequent differential diagnoses comprise e.g. scabies, impetigo, varicella, tinea, urticaria, mastocytosis and psoriasis. In children, pruritus is most often associated with severe scratching leading to artefacts. This group of patients requires a therapeutical regimen of its own. The use of topical and systemic treatments depends on the underlying aetiology of pruritus and the stage and status of the skin. The physician has to consider that topically applied drugs may cause intoxication due to the different body volume/body surface proportion, especially in newborns and infants. The dosages of systemic drugs need to be adapted in children and UV phototherapy should be performed with caution due to possible longterm photo damage of the skin. Physicians feel more insecurity treating pruritus in children, especially when systemic treatments are taken into consideration. We want to highlight the major aetiologies of pruritus in children and point out the cornerstones of antipruritic therapy in this challenging group of patients in recognition of our own clinical experiences and the current literature.