1. Use and abuse of topical steroids
Mrs Sue Paterson MA Vet MB DVD Dip ECVD MRCVS
RCVS and European Specialist in Veterinary Dermatology
Rutland House Referral Hospital St Helens

2. What do steroids do?
Which steroids should we use in which situation?
How can we use those properties to advantage and avoid side effects?

3. How do glucocorticoids affect the body?
Liver – increased gluconeogenesis, increased glycogen stores
Muscle – increased protein catabolism causing muscle wastage and weakness
Bone – osteopaenia - increased protein catabolism & negative Ca balance
Kidney – increased GFR, interference with vasopressin release or action, increased Ca excretion

4. How do steroids affect the skin ?
Immune system – reduced inflammatory response, reduced immune response
Skin – increased protein catabolism. Atrophic changes within the skin

5. Immune system
Eosinophils – reduced formation in bone marrow, reduced survival time
Mast cells – reduce mast cell numbers and histamine synthesis
Neutrophils – increased release from bone marrow & neutrophilia - reduced margination & diapedesis into tissues. Reduction in chemotaxis, adherence & enzyme secretion
Humural immunity – reduction in Ig production after high dose long term therapy

6. Skin
Epidermal atrophy causing skin thinning, poor wound healing and poor scar formation, skin bruises easily
Follicular keratosis, atrophy and telogenisation of hair follicles
Sebaceous gland atrophy

7. Which topical steroids should we use ?
Steroid absorption
Steroid potency

8. Absorption of steroids
Factors that influence absorption
High concentrations
Abraded or inflamed skin
Occlusive dressings
Steroid vehicle – gel v ointment

9. Shows adrenal suppression is concentration and vehicle dependent
Aniya JS Griffin CE The effect of otic vehicle and conc of dexamethasone on liver enzyme activity and adrenal function in small breed healthy dogs Vet Derm 19(4)
Comparison of liver function tests & ACTH stimulation tests in 3 groups of dogs treated over 2 weeks 2 x daily
Grp % dexameth in saline, Grp % dexameth in saline, Grp % commercial otic prep.
Group 1 – 6/6 dogs no changes on ACTH or liver tests
Group 2 – 4/7 adrenal suppression but not liver enzymes
Group 3 – 4/6 adrenal suppression & 3/6 marked suppression, 1 dog mild liver enzyme changes
Shows adrenal suppression is concentration and vehicle dependent

10. Absorption of steroids
Factors that influence absorption
High concentrations
Abraded or inflamed skin
Occlusive dressings
Steroid vehicle – gel v ointment

11. Thomas RC Logas D et al. Effects of a 1% hydrocortisone conditioner on haematological and biochemical parameters, adrenal function testing and cutaneous reactivity to histamine in normal and pruritic dogs Vet Derm 10(2),
1% hydrocortisone leave on conditioner applied 2 x weekly for 6 weeks to normal and pruritic dogs
In normal dogs – no changes were seen in haematology, biochemistry or ACTH stimulation tests
In pruritic dogs – ACTH stimulation tests were depressed SAP was increased significantly but still in normal range
Histamine reactivity unchanged in both groups
Shows that topical steroid absorption is enhanced through inflamed skin

12. Which topical steroids should we use ?
Steroid absorption
Steroid potency

13. Classification of steroid potency
UK system – 4 grps mild, moderate, potent, very potent
USA system – 7 grps least potent (VII), low (VI), medium (V/IV), med/high (III), high (II), ultra-high (I)

14. Topical steroid potency
Topical steroid potency is classified by the individual steroid molecule. Potency can be altered by the drug concentration and if the steroid has been halogenated, methylated, acetylated or esterified Potency can be altered by the vehicle e.g. ointment, cream or gel

15. Potency is an intrinsic property of the
drug and is not the same as concentration
Betamethasone dipropionate 0.05% is more potent than Hydrocortisone 1%. Betamethasone is a more potent steroid than hydrocortisone despite it only being 1/20 of the concentration
Concentration is only important when the
same molecules are compared
Triamcinolone acetonide cream 0.5% is more potent than Triamcinolone acetonide cream 0.1%

16. How chemical changes in the steroid change potency
Halogenation, methylation, acetylation or
esterification of a steroid will increase its
potency
Hydrocortisone 1% spray VII least potent
Hydrocortisone aceponate % spray
(HC ester) IV/V medium strength

17. How the vehicle changes the potency
Ointments provide lubrication but are occlusive. Occlusion improves steroid absorption.
Creams provide lubrication but are less occlusive than ointment. Creams are generally less potent than ointment of the same medication
Lotion and gels are the least greasy & occlusive of all topical steroid vehicles.
Betamethasone valerate ointment Grp III med/high potency
Betamethasone valerate cream/gel Grp IV/V medium potency

18. Use of specific topical glucocorticoid products

19. Potency of some topical steroids
VII Least potent 1% Hydrocortisone spray, gel*
VI Low strength 0.1% dexameth lotion*, % triamcin acetonide spray*
IV/V Mid-low strength % HC aceponate spray*, 0.1% betameth valerate gel* 0.1% triamcin acetonide ointment*
III Upper mid strength 0.1% Momet furoate oint*
II Potent 0.05% betameth dipropionate ointment
I Ultra potent 0.05% clobetasol propionate

20. Hydrocortisone aceponate
IV/V Mid-low strength % HC aceponate spray
HCA is lipophilic diester of HC with enhanced skin penetration to produce local efficacy at low dose
HCA is said to have high local activity with reduced systemic effects with minimal atrophogenic effects

21. Efficacy of a 0.584% HCA spray in the TX of CAD : a randomised, double blind placebo controlled trial Nuttall T Mueller R et al Vet Derm 20(3)
Showed HCA significantly improved clinical signs including pruritus versus placebo. Showed no side effects used sid / 28 days then eod / twice wkly / 42 days
Comparable efficacy of a topical 0.584% HCA spray and oral ciclosporin in tx CAD Nuttall T, McEwan NA et al Vet Derm Vol 23(1)
Study compared HCA (2 sprays /100cm2 ) with ciclosporine (5mg/kg) sid over 84 day period. No significant difference in level of control in either grp. By day 84 13/24 HCA and 12/21 ciclosporine were tx eod or 2x wkly

22. General and local tolerance of a 0
General and local tolerance of a 0.584% HCA spray applied daily on dogs for 14 days Rey-Grobellet X et al Proc. 56th SCIVAC Repeated applications of a 0.584% HCA spray for 8 weeks in dogs, impact on skin thickness Reme C et al Vet Derm 19 (1) Both studies showed no cutaneous atrophy with repeated application of the spray
Effect of a novel topical diester G/C spray on immediate and late phase cutaneous allergic reactions in Maltese beagles atopic dogs: a placebo controlled study Bizikova P Linder KE et al Vet Derm 21 (1)
Showed atrophy occurred in axilla and inguinal areas with reduction in immediate and late phase IDT reactions. Ventral axilla, groin and flanks are areas more prone to topical G/C effects

23. Betamethasone valerate gel
IV/V Mid-low strength % betamethasone valerate gel

24. In vitro percutaneous absorption of fusidic acid and betamethasone 17-valerate across canine skin Degim IT et al J.S.A.P. Vol 40, Showed that 10% of betamethasone valerate and 1.3% of fusidic acid penetrated the skin over 24 hour period
Topical fusidic acid / betamethasone containing gel compared to systemic therapy in the treatment of canine acute moist dermatitis Cobb MA et al Vet Journ. 169(2) Comparison of 0.5% fusidic acid and 0.1% betamethasone 17 valerate gel with systemic therapy (dexamethasone and clavamox) in the treatment of 104 dogs with AMD. Good response seen in both grps and no difference between them

25. 2) produce changes in the skin
How to use steroids effectively
1) to regulate the immune system
2) produce changes in the skin

26. 1) Regulation of the immune system
Immune system – reduced inflammatory response, reduced immune response
Anti-inflammatory properties can be used to treat allergic and other inflammatory disease. A reduction in the immune response is useful in autoimmune and neoplastic disease

27. Diseases where topical steroids may be useful
Inflammatory diseases
Hypersensitivity – flea allergy, atopic dermatitis, adverse food reactions
Pyotraumatic dermatitis (hot spots)
Contact dermatitis ( irritant or allergy)
Immune / neoplastic diseases
Immune mediated dermatoses – pemphigus, pemphigoid, DLE)
Neoplasia – epitheliotropic lymphoma

28. Use in inflammatory diseases
Hypersensitivity – flea allergy, atopic dermatitis, adverse food reactions
Pyotraumatic dermatitis (hot spots)
Contact dermatitis ( irritant or allergy)
Aim to use the weakness topical steroid possible. In acute flares use a potent steroid and aim to reduce or withdraw as soon as possible

29. Use in immune mediated or neoplastic disease
Immune mediated dermatoses – pemphigus, pemphigoid, DLE
Neoplasia – epitheliotropic lymphoma
Use a potent topical steroid and taper as quickly as possible

30. When does steroid use become steroid abuse ?

31. How can those properties causes problems ?
Immune system – reduced inflammatory response, reduced immune response
Where the inflammatory or immune response is protective then prevention of this can lead to problems with secondary infection (bacteria, yeast) or parasites (demodex)

32. How can problems be avoided in inflammatory skin disease?
Hypersensitivity – flea allergy, atopic dermatitis, adverse food reactions
Pyotraumatic dermatitis (hot spots)
Contact dermatitis (irritant or allergy)
Questions to ask
Are there any primary lesions?
What does cytology show?
Have the signs improved as expected?

33. Presence of primary lesions
Pustules – evidence of infection ? Often difficult to find but secondary lesions may be present – crust, scale epidermal collarettes
Papules – evidence of infection or ectoparasites ?
Satellite lesions useful to differentiate surface from deep infection in cases of AMD

34. Satellite lesions to help differentiate AMD from deep pyoderma
Satellite lesions never present
Cytology non degenerate polymorphs – rare bacteria
Deep Pyoderma
Satellite lesions present
Cytology degenerate neutrophils bacteria
Topical steroids contraindicated
Topical steroids part of therapy

35. What does cytology show?
Is there just an inflammatory infiltrate present ?
Is there evidence of bacteria ?
Is there evidence of yeast ?
Is there evidence of parasites?
If in doubt use an anti-pathogenic wipe/spray/wash before using topical steroid

36. Have the signs improved as expected?
Has rational topical steroid therapy improved the animal as predicted ?
If therapy is being used excessively e.g. HCA is being used daily to control pruritus suggests it is not appropriate therapy or other causes of pruritus present

37. How can problems be avoided in immune mediated and neoplastic skin disease?
Immune mediated dermatoses – pemphigus, pemphigoid, DLE)
Neoplasia – epitheliotropic lymphoma
Questions to ask
Are there compatible clinical signs?
What does cytology show?
Is it definitely an immune mediated disease?

38. 2) produce changes in the skin
How to use steroids effectively
1) to regulate the immune system
2) produce changes in the skin

39. To produce changes in the skin
Skin – increased protein catabolism causing thin skin. Hair growth and glandular tissue in skin affected
Thinning of the skin is useful where there is chronic hyperproliferative changes. Reduction in glandular secretion useful where there is over production

40. Diseases where topical steroids may be useful
Proliferative otitis – hyperplasia of the wall of the canal with ceruminous and sebaceous gland hyperplasia
Chronic skin change where the skin is lichenified and hyperplastic

41. When does steroid use become steroid abuse ?

42. How can those properties causes problems ?
Skin – thin skin, poor wound healing, poor scar formation, skin bruises easily
The ability of a topical steroid to thin the skin is not useful if the skin is normal and increased fragility is a disadvantage

43. How can those properties cause problems ?
Skin – Atrophic changes to hair follicles, skin and sebaceous glands
Excessive topical steroids can lead to hair loss and over drying of the skin

44. Take home messages
Use the most appropriate topical steroid based on the case
Allergy - use the weakest steroid and increase potency if required tapering asap
Immune mediated disease - use a potent steroid and taper asap
Use cytology to assess for infection and parasites before starting steroid therapy
Use topical antibacterial and anti-yeast therapy prior to starting topical steroids if necessary