1. Seborrhoea and otitis in a crossbred dog Author: Ross BondEditor: David Lloyd © European Society of Veterinary Dermatology

2. History | Signs | Differentials | Tests | Therapy | Notes Click to reveal the text on this screen Click the forward arrow to jump to the next screen History - 1 History 9-year-old neutered female Collie cross dog Weight 43 kg Has had a dull, somewhat greasy coat for 4 years or more Has always been overweight but gaining more in last 2 years

3. History | Signs | Differentials | Tests | Therapy | Notes History - 2 History Decreased exercise tolerance attributed by owners to weight gain and arthritis (reluctance to exercise) Mild, recurrent head tremor noted on several occasions in the past year Chews and licks feet but not a severe problem, has itchy ears Dog is bright, appetite good, thirst unchanged (1.8-2.0 litres/day)

4. History | Signs | Differentials | Tests | Therapy | Notes History - 3 History Neomycin + betamethasone drops for otitis - little improvement Etiderm (ethyl lactate shampoo) - resolved pedal pruritus but erythema remained. Relapse after 6 weeks Prednoleucotropin (PLT), 1-2 twice daily for arthritis. Some improvement Efavet 660, 1 twice daily. No effect

5. History | Signs | Differentials | Tests | Therapy | Notes Clinical signs - 1 Signs Bright, alert dog Heart rate 110 beats per minute Rectal temperature 100.5 o C Mild generalised seborrhoea Mild erythema and hyperpigmentation of interdigital skin Moderate ceruminous otitis

6. History | Signs | Differentials | Tests | Therapy | Notes Clinical signs - 2 Signs The dog was overweight The coat was long, thick and greasy

7. History | Signs | Differentials | Tests | Therapy | Notes Clinical signs - 3 Signs Anterior and dorsal views of the dog

8. History | Signs | Differentials | Tests | Therapy | Notes How would you approach this case? Signs What are the next steps you would take? Make a list of your principle differential diagnoses List any samples you would collect List any tests you would perform to assist in making a definitive diagnosis

9. History | Signs | Differentials | Tests | Therapy | Notes Case investigation Differentials Principle differential diagnoses Ewan - what would you include?

10. History | Signs | Differentials | Tests | Therapy | Notes Tests Skin scrapings from feet..... Ewan where else? Tape strips from interdigital spaces......? Blood tests Routine haematology Biochemistry panel

11. History | Signs | Differentials | Tests | Therapy | Notes Results Tests Scrapings did not reveal ectoparasites Tape strips demonstrated substantial numbers of Malassezia in the interdigital spaces Haematological and biochemical profiles were within accepted limits

12. History | Signs | Differentials | Tests | Therapy | Notes What now? What treatment, if any, should you now institute? What are now your principle differential diagnoses? Are there any other samples you would collect? Tests

13. History | Signs | Differentials | Tests | Therapy | Notes Initial therapy Ectoparasitism was deemed unlikely Malassezia numbers indicated infection necessitating therapy Owner was instructed to bathe the feet using Malaseb Shampoo twice weekly. Allowing a 10 minute contact time before rinsing. Tests

14. History | Signs | Differentials | Tests | Therapy | Notes What is your diagnosis? What is your principle diagnosis? Do the investigations permit a definitive diagnosis? Are there any additional investigations which you think may need to be done? Tests

15. History | Signs | Differentials | Tests | Therapy | Notes Further tests Tests Total T 4 and endogenous TSH were measured, Results Total T 4 = 12.7 µmol/l (13-52) Endogenous TSH = 0.47 µg/ µl (<0.41) What does this mean?

16. History | Signs | Differentials | Tests | Therapy | Notes Diagnosis Hypothyroidism diagnosis supported by: Low total T 4 and elevated TSH levels Dog overweight Poor exercise tolerance Susceptibility to skin infection Hypertrichosis Tests

17. History | Signs | Differentials | Tests | Therapy | Notes How would you deal with this case? What is your prognosis? How will you advise the owner? What treatment would you institute? Tests

18. History | Signs | Differentials | Tests | Therapy | Notes Prognosis Prognosis is good Hypothyroidism normally responds well to therapy with thyroxine Hypothyroidism may explain many, if not all of the clinical problems in this case Tests

19. History | Signs | Differentials | Tests | Therapy | Notes Therapy Thyroxine administered at 10 ug/kg twice daily for 12 weeks then the 4 hour post-T 4 basal plasma total T 4 measured and gave a value of 35 nmol/l Maintenance therapy was then established at 15 ug/kg of thyroxine twice daily Response. Loss of all hair apart from a short 2-3 cm coat, over a 3 month period

20. History | Signs | Differentials | Tests | Therapy | Notes Response to therapy Coat then grew gradually to form a normal coat Weight decreased to 32kg over 12 months Exercise tolerance and mobility improved Head tremor absent Coat improved but still some greasiness Continuing mild otitis externa No pruritus Therapy

21. History | Signs | Differentials | Tests | Therapy | Notes Points to consider - 1 Notes How do you asses the significance of Malassezia Tape strips and surface culture methods only identify superficial populations. Some cases without elevated surface populations will respond to anti- yeast therapy Could ketoconazole have been used to deal with the Malassezia? Signs were mild and did not justify ketoconazole an unlicensed product. Ketoconazole inhibits steroidogenesis and would have complicated the interpretation of subsequent endocrine assessments

22. History | Signs | Differentials | Tests | Therapy | Notes Points to consider - 2 Notes Why is hypertrichosis sometimes a feature of hypothyroidism? Thought to be caused by slowed hair cycle turnover - telogen hairs not shed and resultant thick coat It is a common feature of equine hypothyroidism In dogs it is seen particularly in setters

23. History | Signs | Differentials | Tests | Therapy | Notes Review Notes If you would like to review this case, please use the navigation buttons below