Comparison of once-daily versus twice-weekly terbinafine administration for the treatment of canine Malassezia dermatitis - a pilot study

A single-blind randomised study comparing the efficacy of fluconazole and itraconazole for the treatment of Malassezia dermatitis in client-owned dogs

BACKGROUND

No reports have compared the clinical therapeutic efficacy of fluconazole and itraconazole in canine Malassezia dermatitis.

OBJECTIVES

The study aimed to compare the clinical therapeutic efficacy of fluconazole and itraconazole and to evaluate the adverse effects of fluconazole in canine Malassezia dermatitis.

ANIMALS

Sixty-one client-owned dogs with Malassezia dermatitis.

MATERIALS AND METHODS

The enrolled animals were randomly divided into groups receiving 5 mg/kg fluconazole (5FZ), 10 mg/kg fluconazole (10FZ) or 5 mg/kg itraconazole (5IZ). The drugs were orally administered once daily for 28 days. Cytological examination, clinical index score (CIS), pruritus Visual Analog Scale (PVAS) evaluation and blood analysis (for 5FZ only) were performed on Day (D)0, D14 and D28.

RESULTS

On D14, significant reductions in mean yeast count (MYC), CIS and PVAS were observed in the 5FZ (n = 20, p < 0.01), 10FZ (n = 17, p < 0.01) and 5IZ (n = 16, p < 0.05) groups. In all three groups, a significant reduction (p < 0.001) in MYC, CIS and PVAS expression was observed on D28. There was no significant difference in the percentage reduction of MYC, CIS and PVAS among the groups. Moreover, there was a significant difference (p < 0.05) in each group between D14 and D28, except for the percentage reduction in MYC in the 10FZ and 5IZ groups. No adverse effects of fluconazole were observed in the 5FZ or 10FZ groups.

CONCLUSIONS AND CLINICAL RELEVANCE

This study indicates that 5FZ and 10FZ are as effective as itraconazole in canine Malassezia dermatitis.

Malassezia: Zoonotic Implications, Parallels and Differences in Colonization and Disease in Humans and Animals

Malassezia spp. are commensals of the skin, oral/sinonasal cavity, lower respiratory and gastrointestinal tract. Eighteen species have been recovered from humans, other mammals and birds. They can also be isolated from diverse environments, suggesting an evolutionary trajectory of adaption from an ecological niche in plants and soil to the mucocutaneous ecosystem of warm-blooded vertebrates. In humans, dogs and cats, Malassezia-associated dermatological conditions share some commonalities. Otomycosis is common in companion animals but is rare in humans. Systemic infections, which are increasingly reported in humans, have yet to be recognized in animals. Malassezia species have also been identified as pathogenetic contributors to some chronic human diseases. While Malassezia species are host-adapted, some species are zoophilic and can cause fungemia, with outbreaks in neonatal intensive care wards associated with temporary colonization of healthcare worker’s hands from contact with their pets. Although standardization is lacking, susceptibility testing is usually performed using a modified broth microdilution method. Antifungal susceptibility can vary depending on Malassezia species, body location, infection type, disease duration, presence of co-morbidities and immunosuppression. Antifungal resistance mechanisms include biofilm formation, mutations or overexpression of ERG11, overexpression of efflux pumps and gene rearrangements or overexpression in chromosome 4.

Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds.

OBJECTIVES

The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats.

METHODS AND MATERIAL

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document.

CONCLUSIONS AND CLINICAL IMPORTANCE

There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well recognised and diagnostic approaches are well developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected.

Antifungal Resistance Regarding Malassezia pachydermatis: Where Are We Now?

Malassezia pachydermatis is a yeast inhabiting the skin and ear canals in healthy dogs. In the presence of various predisposing conditions it can cause otitis and dermatitis, which are treated with multiple antifungal agents, mainly azole derivatives. This manuscript aims to review the available evidence regarding the occurrence of resistance phenomena in this organism. Various findings support the capacity of M. pachydermatis for developing resistance. These include some reports of treatment failure in dogs, the reduced antifungal activity found against yeast isolates sampled from dogs with exposure to antifungal drugs and strains exposed to antifungal agents in vitro, and the description of resistance mechanisms. At the same time, the data reviewed may suggest that the development of resistance is a rare eventuality in canine practice. For example, only three publications describe confirmed cases of treatment failure due to antifungal resistance, and most claims of resistance made by past studies are based on interpretive breakpoints that lack sound support from the clinical perspective. However, it is possible that resistant cases are underreported in literature, perhaps due to the difficulty of obtaining a laboratory confirmation given that a standard procedure for susceptibility testing of M. pachydermatis is still unavailable. These considerations highlight the need for maintaining surveillance for the possible emergence of clinically relevant resistance, hopefully through a shared strategy put in place by the scientific community.

Successful Treatment of Canine Sporotrichosis with Terbinafine: Case Reports and Literature Review

Sporotrichosis occurs worldwide, and the metropolitan region of Rio de Janeiro, Brazil, is a main endemic area, with a large number of human and animal cases in the last 19 years. This mycosis is more frequently described in cats rather than in dogs. There are a limited number of oral antifungal agents for the treatment of sporotrichosis in animals. In this context, the effectiveness of terbinafine in the treatment of sporotrichosis in humans, as well as the promising results of in vitro susceptibility tests, inspired us to use this drug in the therapy of this mycosis in dogs. We reported for the first time the use of terbinafine in the treatment of two dogs with sporotrichosis caused by Sporothrix brasiliensis. Moreover, we provided an overview of therapeutic features of canine sporotrichosis cases reported since the 1960s. One of the dogs presented the fixed cutaneous form of the disease, while the other patient presented hyperemia of the nasal mucosa and respiratory signs only. Terbinafine showed high antifungal activity in vitro against the canine Sporothrix isolates. The dogs were successfully treated with terbinafine, with remission of all clinical signs initially presented. The current reports indicate that this drug can emerge as a therapeutic option for canine sporotrichosis.

Evaluation of a single-administration ototopical treatment for canine otitis externa: a randomised trial

Objective

To evaluate the efficacy and safety of a new, single-administration Otic Solution containing florfenicol, terbinafine and mometasone furoate for the treatment of canine otitis externa (OE).

Design

The clinical efficacy and safety study was a multicentre, controlled, masked and randomised field study conducted over 30 days. Two hundred and twenty-one (221) client-owned dogs of varying breeds with diagnosed bacterial and/or fungal OE were enrolled.

Procedure

Dogs were randomised to either Otic Solution or control groups. Evaluations were conducted over a minimum period of 30 days with a primary effectiveness endpoint based on the improvement in a clinical severity score at the final visit (day 30). Safety analyses were based on clinical and laboratory parameters and the occurrence of adverse events.

Results

The Otic Solution group demonstrated a significantly higher treatment success rate compared with that observed for the control group (72.5 per cent v 11.1 per cent, P value=0.0001) for cases of OE caused by Staphylococcus pseudintermedius and Malassezia pachydermatis. No significant safety findings were reported.

Conclusions/clinical relevance

This new ototopical formulation provides safe and effective treatment of canine OE and is an important alternative antimicrobial for this indication. The single-administration dosage regimen eliminates opportunities for client dosage administration errors and medication stockpiling.

Diagnosis and treatment of dermatophytosis in dogs and cats.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

Dermatophytosis is a superficial fungal skin disease of cats and dogs. The most common pathogens of small animals belong to the genera Microsporum and Trichophyton. It is an important skin disease because it is contagious, infectious and can be transmitted to people.

OBJECTIVES

The objective of this document is to review the existing literature and provide consensus recommendations for veterinary clinicians and lay people on the diagnosis and treatment of dermatophytosis in cats and dogs.

METHODS

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to September 2016. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) provided guidance and oversight for this process. A draft of the document was presented at the 8th World Congress of Veterinary Dermatology (May 2016) and was then made available via the World Wide Web to the member organizations of the WAVD for a period of three months. Comments were solicited and posted to the GP electronically. Responses were incorporated by the GP into the final document.

CONCLUSIONS

No one diagnostic test was identified as the gold standard. Successful treatment requires concurrent use of systemic oral antifungals and topical disinfection of the hair coat. Wood's lamp and direct examinations have good positive and negative predictability, systemic antifungal drugs have a wide margin of safety and physical cleaning is most important for decontamination of the exposed environments. Finally, serious complications of animal-human transmission are exceedingly rare.

Treatment of refractory sino-nasal aspergillosis with posaconazole and terbinafine in 10 dogs

OBJECTIVES

To determine the safety and efficacy of posaconazole and terbinafine for the treatment of naturally occurring sino-nasal aspergillosis in dogs refractory to conventional topical and systemic treatment.

MATERIALS AND METHODS

Ten client-owned dogs with sino-nasal aspergillosis and not responsive to conventional treatments were prospectively enrolled to receive a dose of 5 mg/kg posaconazole orally every 12 hours for six months. All dogs were concurrently treated with doses of 30 mg/kg terbinafine orally every 12 hours and 5 mg/kg doxycycline orally every 12 hours for 6 to 18 months.

RESULTS

All 10 enrolled dogs completed the study. The treatment response was defined as complete clinical remission (n=7) or partial clinical remission (n=3). Two dogs relapsed after cessation of combination therapy. All dogs lived more than one year after starting combination therapy and eight dogs are alive at the time of writing. No clinically relevant adverse reactions or increases in hepatic enzyme activity occurred during the combination therapy.

CLINICAL SIGNIFICANCE

The results of this study suggest that this combination therapy appears safe and well-tolerated for the treatment of refractory sino-nasal aspergillosis in dogs. Long-term survival is possible with prolonged treatment, but relapse is possible. Larger prospective studies are warranted to further evaluate these preliminary findings.

Determining canine skin concentrations of terbinafine to guide the treatment of Malassezia dermatitis

BACKGROUND

Terbinafine (TBF) is known to concentrate and persist in human skin. Its use is increasing in veterinary medicine, but there are limited data concerning its tissue concentration and efficacy in dogs.

HYPOTHESIS/OBJECTIVES

(i) Describe TBF accumulation in canine skin; (ii) Integrate pharmacokinetic data with historical minimum inhibitory concentration (MIC) results for Malassezia pachydermatis to verify the currently used dosage of TBF for the treatment of Malassezia dermatitis.

ANIMALS

Ten healthy, client-owned dogs.

METHODS

Dogs were given TBF (generic preparation, 250 mg tablets) 30 mg/kg per os (p.o.) once daily for 21 days. Serum, sebum and stratum corneum (SC) samples were collected on days 1, 5, 7, 11, 14, 21, 28 and 35. High-pressure liquid chromatography was used to determine drug concentrations in samples.

RESULTS

Relevant (mean ± standard deviation) parameters for TBF in serum, paw SC, thorax SC and sebum, respectively, were: maximum concentration (Cmax , μg/mL) 23.59 ± 10.41, 0.31 ± 0.26, 0.30 ± 0.32 and 0.48 ± 0.25; half-life (t1/2 , d) 4.49 ± 2.24, 6.34 ± 5.33, 4.64 ± 3.27 and 5.12 ± 3.33; time to maximum concentration (Tmax , d) 10.40 ± 6.98, 13.20 ± 5.16, 11.90 ± 8.62 and 10.60 ± 3.69.

CONCLUSIONS AND CLINICAL IMPORTANCE

These results suggest that TBF does not achieve high concentrations in canine SC or sebum compared to serum. The mean Cmax of all skin tissues (paw SC, thorax SC and sebum) barely exceeded the reported Malassezia MIC90, of 0.25 μg/mL, which indicates that doses higher than 30 mg/kg p.o. once daily may be necessary.

Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA)

Background

In 2010, the International Task Force on Canine Atopic Dermatitis (now International Committee on Allergic Diseases of Animals, ICADA) published the first consensus guidelines for the treatment of atopic dermatitis (AD) in dogs. This is the first 5-year minor update of this document.

Results

The treatment of acute flares of AD should involve the search for, and then elimination of, the cause of the flares, bathing with mild shampoos, and controlling pruritus and skin lesions with interventions that include topical and/or oral glucocorticoids or oclacitinib. For chronic canine AD, the first steps in management are the identification and avoidance of flare factors, as well as ensuring that there is adequate skin and coat hygiene and care; this might include more frequent bathing and possibly increasing essential fatty acid intake. The medications currently most effective in reducing chronic pruritus and skin lesions are topical and oral glucocorticoids, oral ciclosporin, oral oclacitinib, and, where available, injectable recombinant interferons. Allergen-specific immunotherapy and proactive intermittent topical glucocorticoid applications are the only interventions likely to prevent or delay the recurrence of flares of AD.

Conclusions

This first 5-year minor update of the international consensus guidelines for treatment of AD in dogs further establishes that the treatment of this disease is multifaceted, and that interventions should be combined for a proven (or likely) optimal benefit. Importantly, treatment plans are likely to vary between dogs and, for the same dog, between times when the disease is at different stages.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-015-0514-6) contains supplementary material, which is available to authorized users.