Successful treatment of pruritus with topical tacrolimus in a patient with primary biliary cirrhosis

Itching as the onset of pain (part 2)

Itching of the skin is a particularly unpleasant subjective sensation that causes the need to scratch. Physiological itching occurs in response to environmental irritants (friction, insect crawling, temperature changes, etc.) and disappears after elimination of the cause. Pathological itching is caused by changes in the skin or throughout the body and causes a strong need to get rid of itching by combing or any other method. Itching is a common symptom of local (dermatological) or general (systemic) disease. It can be limited (localized) or diffuse (generalized).One of the causes of itching is often noted endocrine diseases and metabolic disorders: hyper- and hypofunction of the thyroid gland, diabetes mellitus and hyperparathyroidism. In thyroid hyperfunction, generalized (inconstant and little-pronounced) itching of the skin is observed in the clinical picture only in 10 % of patients. It is accepted that itching of the skin in thyrotoxicosis syndrome is due to increased activity of kinin in combination with an increase in major metabolism and an increase in body and skin temperature (123).Itching caused by impaired bile secretion is characteristic of many diseases of the liver: primary biliary cirrhosis, sclerosing cholangitis, viral hepatitis caused by cholestasis medications and other causes of obstructive jaundice. It is in these cases that prurigo is usually generalized, but in some typical cases it is more pronounced on the feet and palms. With this pathology, itching is caused by obstruction of the biliary tract, however, and to this day, no close correlation has been found between serum bilirubin and the severity of itching.If it was previously thought that itching in pathology of the peripheral or central nervous system, such as multiple sclerosis, neuropathy, compression or irritation of nerves (e.g., paraesthetic dorsalgia, brachioradial itching) is also a significant symptom, then modern studies prove that in more cases, itching is not characteristic of most pathologies of the nervous system, so after a detailed anamnesis, examination and initial research, the patient should be referred to a related specialist, except in cases of about obvious postherpetic neuropathy, painless paresthesia, or brachioradial itching, which can often be guided in the provision of primary care.Instead, there are some psychological conditions and a number of psychiatric illnesses (obsessive-compulsive disorders, depression, and parasite illusions) that are most commonly diagnosed with the exclusion method. Neurotic squabbles are scattered on the body of the excorii, covered with scales that may occur in any area of the body that the patient may reach, but are often limited by limbs.

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.

Effects of topical application of tacrolimus on acute itch-associated responses in mice

Using mice, we examined whether the topical application of tacrolimus would produce an acute anti-pruritic effect. An itch-related response, scratching, was elicited by intradermal injections of mosquito allergen (10 microg/site) in sensitized mice and SLIGRL-NH2 (protease-activated receptor-2 agonist, 50 nmol/site), histamine (100 nmol/site), serotonin (100 nmol/site) and substance P (100 nmol/site) in naive ones. Topical application of 1%, but neither 0.1% nor 0.3%, tacrolimus to the skin 1 h before injection inhibited scratching induced by mosquito allergen and SLIGRL-NH2, without effects on scratching induced by histamine, serotonin, and substance P. Topical tacrolimus also inhibited licking induced by an intraplantar injection of capsaicin (0.1 microg/site). These results suggest that topical tacrolimus exerts acute inhibitory effects on allergic and protease-activated receptor-2-mediated itching. Though precise mechanisms remain unclear, the action on sensory neurons expressing protease-activated receptor-2 and transient receptor potential vanilloid-1 capsaicin receptor may be involved in the inhibitory effects of tacrolimus.

Pruritus in primary biliary cirrhosis: pathogenesis and therapy

Pruritus is a symptom experienced by patients who have primary biliary cirrhosis. It seems to result from pruritogens that (as a result of cholestasis) accumulate in plasma and other tissues, and which lead to altered neurotrasnmission. Administration of medications that change opioid neurotransmission (ie, opiate antagonists) results in relief of pruritus and its behavioral manifestation, scratching. Through unknown mechanisms, other centrally acting medications, including antidepressants, may have ameliorating effects on the pruritus of cholestasis. Stimulating endogenous detoxification pathways in the liver may also lead to the amelioration of pruritus. The removal of pruritogens through administration of nonabsorbable resins, nasobiliary drainage, biliary diversion, plasmapheresis, and various dialysis procedures is reported to decrease pruritus in liver disease, although the substances that are presumably removed are unknown.

Assigning new roles to topical tacrolimus

Tacrolimus is an ascomycin macrolactam derivative with immunomodulatory and anti-inflammatory activity that belongs to the class of calcineurin inhibitors. Tacrolimus in its topical formulation has been established as a safe and effective alternative to topical corticosteroids because of its mild side effects and its minimal systemic absorption. Topical tacrolimus has been approved for the treatment of atopic dermatitis in two concentrations, 0.03 and 0.1%. In a thorough research of literature the authors review all of the available data regarding the off-label uses of the medication in other dermatoses. It seems that compared to pimecrolimus, tacrolimus has proved to be a more effective treatment. There is no causal relationship that has been established between tacrolimus and carcinogenesis. Furthermore, the authors believe that, without any evidence, the theoretical concerns are not enough to produce warnings. Tacrolimus ointment 0.1% may be recommended as a first-line choice for seborrheic dermatitis of the face and trunk, facial and intertriginous psoriasis and probably for allergic contact dermatitis and Zoon's balanitis. It has been ineffective in numerous dermatoses such as alopecia areata, necrobiosis lipoidica, internal pruritus and in thick hyperkeratotic plaques of psoriasis when administered as the commercially available formulation without occlusion. There is yet unexploited therapeutic potential regarding the use of topical tacrolimus in dermatology. Isolated cases of successful administration of the medication in various cutaneous conditions require further large-scale studies to clarify the actual effectiveness.

The role of topical calcineurin inhibitors for skin diseases other than atopic dermatitis

The topical calcineurin inhibitors (TCIs) pimecrolimus and tacrolimus are approved for atopic dermatitis but have additional potential in other inflammatory skin diseases. This article reviews their clinical use in non-atopic dermatitis diseases. In seborrheic dermatitis, asteatotic eczema, and contact dermatitis, TCIs are of great benefit and can compete with topical corticosteroids. In psoriasis, TCIs have shown clinical efficacy and safety in facial and intertriginous lesions. Further investigations into possible combinations of TCIs with other established treatments such as UVB irradiation in this disorder are necessary. Initial studies in cutaneous lupus erythematosus have been promising, whereas the response in rosacea and rosacea-like eruptions has been mixed. TCIs have been associated with good clinical responses in oral lichen planus and anogenital lichen sclerosus et atrophicus. In vitiligo, TCIs are associated with some degree of repigmentation, with better results being seen in children and in facial and neck areas. TCIs have a synergistic effect with UVB irradiation in vitiligo. There is a long list of small series and case reports documenting use of TCIs in various other skin conditions that warrant further validation. Although the established mode of action of TCIs is T-cell control, other effects also need to be considered. Specifically, TCIs reduce pruritus and erythema, which cannot be explained by T-cell interactions, and further investigations are needed in these fields.

Basic immunosuppressive drugs outside solid organ transplantation

Immunosuppressive drugs are the backbone of solid organ transplantation. The introduction of new immunosuppressive drugs led to improved patient and organ survival rates. Nowadays, acute rejection can be reduced to a minimum. Individualization and avoidance of drug-related adverse effects became a new goal to achieve. The potency of immunosuppressive drugs makes them attractive for use in various autoimmune diseases; therefore, the experience on immunosuppressive drugs outside the field of organ transplantation is analysed in this review.