Investigation on the use of 0.3% tacrolimus lotion for canine atopic dermatitis: a pilot study

A randomized double-blind clinical trial: Comparison of oclacitinib with a traditional Chinese herbal medicine product (Dihuang Guiqin capsule) in the treatment of canine atopic dermatitis

Canine atopic dermatitis (cAD) is a common chronic inflammatory skin disease, which seriously affects the quality of life for both dogs and their owners. Currently, the common therapeutic drugs in the clinic have disadvantages such as obvious adverse effects and high prices. Traditional Chinese herbal medicine (TCHM) has great potential for the treatment of cAD. The aim of this study is to compare the effects of different doses of the TCHM product (Dihuang Guiqin capsule) and oclacitinib in the treatment of cAD through a randomized, double-blind trial. Sixty dogs diagnosed with AD were randomly and evenly divided into four groups (n = 15). The TCHM treatment group consisted of three subgroups that received three different oral doses (20, 40, and 60 mg/kg BW), while the control group received 0.5 mg/kg BW of oclacitinib. Each group was administered twice daily for 14 consecutive days. The results showed that both TCHM and oclacitinib significantly improved cAD-induced itching (evaluated by pVAS) and skin lesions (evaluated by CADESI-04), while interleukin 31 (IL-31) concentrations decreased significantly (P < 0.05) and serum biochemical indicators returned to normal. In particular, The therapeutic effects of TCHM medium- and high-dose groups were similar to those of oclacitinib (P > 0.05). The preliminary recommended dose of Dihuang Guiqin capsule for the treatment of cAD has been determined to be 40-60 mg/kg BW twice daily for 14 consecutive days, which can be reduced to once daily as appropriate. Dihuang Guiqin capsule was safe and well tolerated, which may be a new option for the treatment of cAD.

A proposed medication score for long-term trials of treatment of canine atopic dermatitis sensu lato

BACKGROUND

The use of concurrent medications is necessary in trials of treatment of canine atopic dermatitis. Our aim was to use the best available evidence to construct and then to validate a medication score (MS) formula that will estimate the impact of concurrent medications on trial outcomes.

METHODS

Trials of 15 interventions were scrutinized to find those that were consistent in terms of specific medication, administration route and dosage regimen. A MS was constructed in five steps, starting from assigning a score of 1 for each day on oral prednisone, prednisolone or methylprednisolone at 0.5-1.0 mg/kg. The MS score was validated using the clinical records of 35 dogs with atopic dermatitis that had been treated for a period of 12 ± 2 weeks with six of these medications and compared with a previously published non-validated MS.

RESULTS

A MS could be assigned to eight treatments, six of which had been administered to the 35 dogs. A positive correlation was seen with the previously published MS and a negative correlation with changes in lesional and pruritus scores.

CONCLUSION

This MS may be a useful tool in new studies evaluating the efficacy of treatments in canine atopic dermatitis.

Therapies in Canine Atopic Dermatitis: An Update

Canine atopic dermatitis (AD) is one of the most common inflammatory skin diseases in dogs. The pathogenesis is complex and not completely understood. Many therapeutic options are available; however, because of cost, side effects, or a long lag phase, new compounds are constantly produced. This article provides a comprehensive review of the latest compounds for the treatment of canine AD. In addition, a brief review of new studies on conventional medications is provided. For a successful long-term therapeutic approach, it is important to considerate the status of the disease, as well as the patients' and their owners' needs.

Development of an owner-assessed scale to measure the severity of pruritus in dogs

Assessment of pruritus is critical in dermatological history taking, both for initial diagnosis and for monitoring treatment. Various methods of assessing pruritus in the dog have been described but none have been validated. In this study, four different pruritus scales were initially assessed: a 0-5 numerical scale; a scale containing six categories of pruritic behaviours; a scale with six basic descriptors of severity; and a visual analogue scale with severity descriptions at either end. One hundred and sixteen owners were asked to grade their dog's pruritus with each of the four scales given to them in a randomized order, and asked which they thought was easiest to use, which was most accurate in assessing their dog's pruritus level, and which two scales they would combine to make a superior scale. Pruritus scores from different scales were highly correlated with each other, but scores were significantly higher with the severity and numerical scales compared to the behaviour scale. Based on the clients' responses, a new scale was developed that combined features of the behaviour and severity-based scales with the visual analogue scale. When tested on 166 different owners, 98% thought it was easy to use and accurate in assessing their dog's pruritus level. In 44 dogs, independent scores obtained by two owners were highly correlated (R = 0.8; P < 0.0001), confirming the scale's repeatability. The new scale proved to be an easy and repeatable method for owners to determine the severity of pruritus in their dog.

Proliferative and necrotizing otitis externa in four cats

Proliferative and necrotizing feline otitis externa is a rare disorder of unknown aetiology. This condition was diagnosed by skin biopsy in three adult domestic shorthair cats (3-5 years old) and one kitten (6 months old). The affected cats had large tan to dark brown-black coalescing plaques covering the concave surface of the pinnae and external ear canals. Friable material from the plaques and a thick exudate occluded the ear canals. The cats had a secondary bacterial and/or yeast otitis. Prior to the histopathological diagnosis, all cats received numerous otic preparations as well as oral antibiotics and corticosteroids without resolution. Histologically, all cases had strikingly similar changes; acanthosis with pronounced hair follicle outer root sheath hyperplasia and neutrophilic luminal folliculitis, follicular keratosis and individually necrotic keratinocytes in the outer root sheath of hair follicles. One case was documented via skin biopsy to have persisted for 4 years. The adult cats were treated with topical 0.1% tacrolimus and all showed marked improvement although one cat was lost to follow up. The lesions completely resolved with topical tacrolimus alone in one cat and topical tacrolimus in addition to oral prednisolone in another cat.

Practical Applications of Topical Therapy for Allergic, Infectious, and Seborrheic Disorders

Topical therapy is extremely important in the management of allergic, infectious, and seborrheic disorders. It can be used as a sole therapy or adjunctive therapy for these disorders, often minimizing the need for systemic therapy. In allergic diseases, pruritus can be decreased by removing allergen, desensitizing the skin or other antipruritic effects. Many agents can also maintain or replace moisture to the skin and have emollient effects. When used for infectious conditions, topical therapy can decrease microbial counts and reduce surface colonization of microbes and help to prevent relapses. Antiseborrheic products function by normalizing keratinocyte turnover rates by reducing epidermal division (keratoplastic), normalizing keratinization, and increasing desquamation (keratolytic). There are many different topical vehicles and modes of application: shampoos, whirlpools, soaks, rinses, sprays, lotions, gels, creams, and ointments. Shampoos are often the most practical and effective. The practitioner needs to become familiar with many active ingredients to learn what products are indicated for specific diseases.

Effect of topical 0.02% tacrolimus aqueous suspension on tear production in dogs with keratoconjunctivitis sicca

OBJECTIVE

To investigate the effect of 0.02% tacrolimus in aqueous suspension on tear production in dogs with keratoconjunctivitis sicca (KCS). Animals studied One hundred five dogs diagnosed with KCS [Schirmer tear test (STT) < or = 10 mm/min and clinical signs of dry eye]. Eyes with marginally decreased STT (11 < or = 15 mm/min) and clinical signs of dry eye were also evaluated.

PROCEDURE

The investigation was conducted in two parts: an initial efficacy study and a subsequent double blinded controlled study. In the efficacy study, the effect of topical tacrolimus (formerly FK-506) on tear production in dogs with primary KCS was evaluated. Dogs were divided into four categories: 1) 59 eyes (38 dogs) naïve to tear stimulation therapy with initial STT < or = 10 mm/min; 2) 28 eyes (21 dogs) naïve to tear stimulation therapy with initial STT 11 < or = 15 mm/min; 3) 30 eyes (15 dogs) maintained successfully on CsA therapy; 4) 47 eyes (24 dogs) unresponsive to CsA therapy. STT and clinical signs were evaluated prior to and after 6 to 8 weeks of twice daily tacrolimus administration. Tacrolimus was substituted for CsA therapy in categories 3 and 4. The controlled study compared the effect of topical tacrolimus in aqueous suspension to administration of the aqueous carrier alone on tear production in 20 dogs with primary KCS.

RESULTS

In the efficacy study, STT increased by 5 mm/min in 84.7%, 25.0%, 26.7% and 51.1% of eyes in categories 1, 2, 3 and 4 respectively after tacrolimus administration. Eighty-three percent of eyes with extremely low initial STT (< or = 2 mm/min), increased 5 mm/min after tacrolimus. In the controlled study, STT increased by 5 mm/min in 7/10 dogs (14/20 eyes) that received tacrolimus and in none of the 10 dogs that received aqueous carrier alone. Dogs receiving just the aqueous carrier were subsequently treated with tacrolimus, and STT increased 5 mm/min in 9 dogs (18/20 eyes) after administration.

CONCLUSIONS

Twice daily administration of 0.02% tacrolimus in aqueous suspension effectively increased tear production in dogs with KCS. Topical tacrolimus is a promising alternative to topical CsA for treatment of KCS and may be beneficial in patients with less than optimal response to topical CsA.

Calcineurin Inhibitors: A Novel Approach to Canine Atopic Dermatitis

The introduction of calcineurin inhibitors represents a major addition to the armamentarium of drugs available to veterinary clinicians for the management of allergic skin diseases. Both cyclosporine and tacrolimus have been proven to be well tolerated and effective for the treatment of atopic dermatitis in dogs. Although broad spectrum in their mechanism of action, they lack the major adverse effects of glucocorticoids and provide an appealing alternative to traditional therapies. The purposes of this article are to review clinically relevant information regarding these agents and to provide tips for maximizing the benefit obtained from these therapies.

Treatment of localized lesions of canine atopic dermatitis with tacrolimus ointment: a blinded randomized controlled trial

This investigator-blinded randomized controlled trial was designed to determine whether tacrolimus ointment (Protopic, Fujisawa Healthcare) decreased the severity of localized lesions of canine atopic dermatitis (AD). Twenty dogs with AD were enrolled if they exhibited lesions on both front metacarpi. Each foot was randomized to be treated with 0.1% tacrolimus or placebo (vaseline) ointment twice daily for 6 weeks. Before, and every 2 weeks during the study, erythema, lichenification, oozing and excoriations each were graded on a 10-point scale (maximal total score: 40). The primary outcome measures were the percentage reduction from baseline of lesional scores and the number of subjects whose scores had decreased by 50% or greater at study end. Intention-to-treat analyses were used. At study onset, lesional scores were not significantly different between sites treated with tacrolimus or placebo. After 6 weeks, the percentage reduction from baseline scores was higher for tacrolimus-treated sites (median: 63%; 95% confidence interval: 39-67) than for placebo-treated feet (median: 3%; confidence interval: -2-13) (Wilcoxon test; P = 0.0003). When tacrolimus was applied, lesions decreased by 50% or greater in 15/20 dogs (75%); these dogs were those that completed the study. In contrast, this benchmark was not reached for any placebo-treated feet (Fisher's test; P < 0.0001). Adverse drug events consisted of minor irritation in some lesional areas treated with tacrolimus. Results of this trial suggest that the application of 0.1% tacrolimus ointment is useful for reducing the severity of localized skin lesions of canine AD.

Investigation on the clinical efficacy and safety of 0.1% tacrolimus ointment (Protopic) in canine atopic dermatitis: a randomized, double-blinded, placebo-controlled, cross-over study

Topical tacrolimus is successfully used in people with atopic dermatitis. Preliminary studies in dogs with atopic dermatitis using tacrolimus in a compounded lotion formulation indicated that tacrolimus significantly decreased erythema and pruritus according to investigator, but no significant improvement was reported by the dog owners. The objectives of this study were to evaluate the clinical efficacy and safety of the commercially available 0.1% tacrolimus ointment (Protopic) in dogs with atopic dermatitis. The study was designed as a double-blinded, placebo-controlled, cross-over study. Selected dogs were allocated to either tacrolimus or placebo for 4 weeks. After 4 weeks there was a wash-out period of 2 weeks and treatments were switched. Twelve dogs completed the study. Clinical signs were scored. Blood samples were collected for complete blood count, chemistry panels and tacrolimus levels at week 0 and 4 of each treatment. Tacrolimus ointment significantly decreased severity of symptoms for both owners and investigators at the end of the trial. When the same dogs received the placebo, there were no differences between week 0 and week 4 scores. Dogs with localized disease responded better than dogs with generalized disease. Tacrolimus was detected in the blood of animals receiving the active ingredient. Levels were below the level of toxicity and no adverse effects were reported in any of the dogs. No changes in complete blood count and chemistry parameters were detected between groups or within groups. In conclusion, tacrolimus appears to be a safe alternative treatment in dogs with atopic dermatitis, especially in those with localized disease.

Investigation on the effects of topical therapy with 0.1% tacrolimus ointment (ProtopicR) on intradermal skin test reactivity in atopic dogs

Tacrolimus ointment (TAC) is an effective treatment for atopic dermatitis in humans and dogs. The purposes of the present study were to evaluate the effect of 4 weeks of TAC on intradermal skin testing (IST), and in case of suppression, to investigate if reactivity returned to baseline by 2 or 4 weeks post treatment. Intradermal skin test was performed using saline, histamine, lipopolysaccharide (LPS, 0.4 mg mL(-1)), house dust (25 PNU mL(-1)) and house dust mite (1 : 40 000 w/v) at weeks 0, 4, 6 and 8 on nine dogs enrolled in a blinded, crossover, clinical trial, using 0.1% TAC or placebo once daily for 4 weeks. Reactions were evaluated at 15 min, and at 4 and 6 h. Ointment was applied after the 15-min evaluation on weeks 0 and 4. Data were analysed using the statistical software SAS System for Windows. At week 4, TAC did not affect 15-min IST, but some reactions in the TAC group were suppressed at 6 h compared to baseline. In the TAC group, 4-h IST reactivity was reduced 2 weeks after discontinuation but returned to baseline by 4 weeks. In conclusion, TAC has no effect on immediate reactions but decreased some late-phase reactions. Therefore, no withdrawal is recommended to evaluate only immediate reactions, but a 4-week withdrawal may be necessary for evaluation of late-phase reactions.

Canine atopic dermatitis: new targets, new therapies

Atopic dermatitis is a common allergic skin disease of complex etiopathogenesis in both humans and dogs. Immediate-type hypersensitivity to environmental allergens that arises as a result of environmental and genetic factors is a major part of the pathogenesis in most but not all patients. Alterations in epidermal barrier function, priming of cutaneous antigen-presenting cells with IgE, intrinsic keratinocyte defects, and even development of autoimmunity are also factors that contribute to the primary disease. Secondary factors, especially infections with Staphylococcus and yeast organisms, strongly influence the course of this skin disease. The relatively recent understanding of the complexities of atopic dermatitis has resulted in changes in diagnostic and therapeutic strategies for the disease. We now know that the best therapeutic approach is to use combinations of multiple modalities individualized for each patient over the course of his or her lifetime.

Evidence-based veterinary dermatology: a systematic review of the pharmacotherapy of canine atopic dermatitis

The efficacy of pharmacological interventions used to treat canine atopic dermatitis, excluding fatty acid supplementation and allergen-specific immunotherapy, was evaluated based on the systematic review of prospective clinical trials published between 1980 and 2002. Studies were compared with regard to design characteristics (randomization generation and concealment, masking, intention-to-treat analyses and quality of enrolment of study subjects), benefit (improvement in skin lesions or pruritus scores) and harm (type, severity and frequency of adverse drug events) of the various interventions. Meta-analysis of pooled results was not possible because of heterogeneity of the drugs evaluated. Forty trials enrolling 1607 dogs were identified. There is good evidence for recommending the use of oral glucocorticoids and cyclosporin for the treatment of canine atopic dermatitis, and fair evidence for using topical triamcinolone spray, topical tacrolimus lotion, oral pentoxifylline or oral misoprostol. Insufficient evidence is available for or against recommending the prescription of oral first- and second-generation type-1 histamine receptor antagonists, tricyclic antidepressants, cyproheptadine, aspirin, Chinese herbal therapy, an homeopathic complex remedy, ascorbic acid, AHR-13268, papaverine, immune-modulating antibiotics or tranilast and topical pramoxine or capsaicin. Finally, there is fair evidence against recommending the use of oral arofylline, leukotriene synthesis inhibitors and cysteinyl leukotriene receptor antagonists.