Imagine this clinical scenario: you are presented with a six-year-old female neutered cat exhibiting recurrent episodes of hair pulling and overgrooming without an apparent underlying medical cause. Fleas and flea allergy have been excluded through a full skin work-up. Although environmental changes have reduced some stressors, the cat continues to overgroom. The owner is worried about the cat’s abdominal and inner thigh baldness and asks whether pharmacotherapy might prevent overgrooming.
You know clomipramine is effective in treating feline urine spraying, so you would like to find out whether it could also be efficacious in treating psychogenic alopecia, another behavioural disorder. You decide to consult the literature to explore whether treatment with clomipramine reduces cat psychogenic alopecia.
The evidence
You reviewed one pseudo-randomised double-blind placebo-controlled trial study (Mertens et al., 2006) that fully addressed the research question. It included 25 cats that had undergone skin analysis to confirm that their alopecia was self-inflicted with no underlying dermatological cause.
The sample included adult cats (aged 4 to 14 years), 56 percent of which were spayed females and 44 percent castrated males. Breeds included mainly domestic shorthairs, and also a couple of domestic longhairs and one Siamese cat. Most cats (88 percent) came from multi-cat households, 24 percent came from households with children and only 8 percent had access to the outdoors. The cats were acquired from a variety of sources.
Twenty-two cats completed the study due to limitations in data capture or treatment administration, and one case of urinary obstruction that necessitated withdrawal.
The studied outcomes were: daily grooming episodes as observed by the owner, alopecia reduction, hair regrowth, adverse events (based on owners’ observations and clinical signs) and general owner evaluation.
Limitations
Limitations of the evidence included the small sample size with no power calculation undertaken. The over-representation of indoor cats and multi-cat households potentially limited the extent to which the findings can be generalised to the overall household cat population. The statistical treatment difference to be detected to conclude that clomipramine was superior to placebo was not specified, and hair regrowth differences across breeds were not discussed.
There were several points of potential bias: alternate instead of random allocation to treatment and placebo groups, the lack of provision of animal details and grooming episode characteristics for each group, and the lack of clarity regarding the investigators blinded to the type of treatment.
Measurement limitations related to the severity of alopecia, cat stress (including effects of positive punishment) and owner and animal compliance with clomipramine administration. Reporting and analysis limitations included the lack of precise mean values and standard deviations of the average number of grooming episodes, and alopecia and hair regrowth scores.
The findings
Mertens et al. (2006) found no significant difference between clomipramine and placebo groups in the number of grooming episodes throughout the clomipramine treatment period and after its discontinuation, or in the score of alopecia and hair regrowth after 28 and 56 days of medication and 28 days after stopping the medication. This may reflect an underpowered study as all three parameters measured suggested clomipramine might have a positive effect, but this cannot be said to be demonstrated in this study.
As information related to the scoring system validation was not provided, it is debatable whether alopecia and hair regrowth scores were specific enough or sufficient to measure medication efficacy
Numerically, mean grooming episodes decreased by approximately half after 56 days of treatment in the clomipramine group followed by a notable rebound in grooming episodes at 84 days (28 days after discontinuation of treatment). By contrast, grooming episodes in the placebo group consistently decreased slightly between days 28 and 84. Twice as many owners (64 percent) in the clomipramine group found their cat’s behaviour and coat improved by at least 50 percent compared to the placebo group (36 percent).
As information related to the scoring system validation was not provided, it is debatable whether alopecia and hair regrowth scores were specific enough or sufficient to measure medication efficacy, especially as the literature has shown that hair growth can depend on different factors such as season, sex, breed and nutrition (Affolter and Moore, 1994; Hendriks et al., 1997).
Implementation of a behavioural and environmental modification plan alongside treatment with clomipramine has been shown to lead to a sustained reduction in overgrooming among cats with psychogenic alopecia
Further, the implementation of a behavioural and environmental modification plan alongside treatment with clomipramine has been shown to lead to a sustained reduction in overgrooming among cats with psychogenic alopecia (Seksel and Lindeman, 1998; Sawyer et al., 1999; Overall and Dunham, 2002). This suggests that the findings of Mertens et al. (2006) cannot be interpreted effectively without considering the environmental changes that may have occurred for some cats enrolled in the study, such as cessation of positive punishment.
Conclusion
Based on the findings of Mertens et al. (2006), there is no evidence that clomipramine alone is effective in treating psychogenic alopecia in cats. However, this study was of limited quality, potentially underpowered to detect a significant effect and had several confounding factors that may have affected the results.
Further research […] is needed to substantiate the efficacy of clomipramine alone or in addition to behavioural and/or environmental therapies in reducing feline psychogenic alopecia
Further research conducted through randomised double-blind controlled trials that limit confounding factors is needed to substantiate the efficacy of clomipramine alone or in addition to behavioural and/or environmental therapies in reducing feline psychogenic alopecia.
| The full Knowledge Summary can be read in RCVS Knowledge’s open access journal Veterinary Evidence. |
Disclaimer
The application of evidence into practice should take into account multiple factors, not limited to individual clinical expertise, patient’s circumstances, owner’s values, the individual case in front of you, the availability of therapies and resources, and the country, location or clinic where you work.
Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.
