The purpose of this study was to establish coat and skin changes in cats suffering from the endocrine diseases diabetes mellitus and hyperthyroidism.

Three groups were recruited:

Group A

Twenty one control cats, >8 years, not suffering from systemic disease. Health was defined by normal results for fructosamine levels, total or free T4, general biochemistry and physical and dermatological examination.

Group B

Twenty cats diagnosed with diabetes mellitus of at least one month's duration, defined by persistent hyperglycaemia and /or repeated, raised fructosamine, along with the clinical signs including: polyuria and polydipsia.

Group C

Twenty five cats diagnosed with hyperthyroidism of at least one month's duration, defined by elevated thyroxine levels (free T4 or total T4 by equilibrium dialysis) and clinical signs including: tachycardia, palpable goitre, polyphagia and weight loss.

After all cats were selected for inclusion, cats were examined for dermatological lesions, specifically excessive scale in the diabetic cat group and pinnal alopecia in the hyperthyroid group. Each cat was scored on a scale of 0-4 for the presence of scale or alopecia. To rule out the complicating factor of primary skin lesions caused by ectoparasites or fungal infection, coat brushings, tape strippings and hair plucks, dermatophyte cultures were performed.

The diet each cat was fed on was recorded for an association between diet and unhealthy coat condition. Body mass index measurements were performed to assess association between obesity and coat condition.

Baseline and outcome data from the three groups were assessed using the ANOVA test and Kruskal Wallis test for continuous data and Chi squared and Fisher's Exact test for categorical data as appropriate (STATA 8). Results were considered significant if p<0.05.

There was a significant association between diabetes mellitus and increased scale (p=0.016 when compared to control cats) yet no significant association between hyperthyroid and pinnal alopecia was found (p=0.121 compared to control cats)

There was no significant difference between the three groups in terms of age profile or breed mix. Diabetics differed in gender mix from control groups (p= 0.003), and were heavier than control groups (p=0.001). Association between scale and overweight status for diabetics was not significant (p= 0.141). Excluding diabetic specific diets, diet was not significantly associated with scale, (p= 0.144). There was no significant association between flea infestation (found equally in all groups) and scurf score in diabetics, (p=0.313).