Equine Dermatology. Sabrina Jacobs, DVM Performance Equine Vets Aiken, SC

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1 Equine Dermatology Sabrina Jacobs, DVM Performance Equine Vets Aiken, SC

2 Introduction: Bacterial Folliculitis Dermatophytosis (Ringworm) Dermatophilosis (Rain Rot) Urticaria (Hives) Culicoides Gnat Hypersensitivity (Sweet Itch) Pemphigus Foliaceous Grease Heel Syndrome (Scratches) Papillomans Sarcoids

3 Topics to be discussed: Etiology Pathogenesis Clinical signs Diagnosis Treatment

4 Bacterial Folliculitis Staphylococcus spp. Opportunistic Infection Crusts, papules, pustules typically in a circular pattern Pruritic (Itchy) Methicillin-resistant staph MRSA Diagnosis by Culture

5 Bacterial Folliculitis

6 Bacterial Folliculitis

7 Bacterial Folliculitis Treatment Remove Crusts Bathe with Chlorhexidine or Malaseb Shampoo (let sit for 15 minutes) Topical Triple Antibiotic or Silver Sulfadiazene Cream Systemic Antibiotics: SMZ (Baytril if resistant) may be necessary Keep dry

8 Dermatophytosis (Ringworm) Trichophyton equinum and T mentagrophytes are the most often fungal organisms identified Warm/Humid Climates Lesions on the limbs and pressure areas Scaling, Crusts, Alopecia (sharply demarcated) Zoonotic AND Contagious between horses Fomites- Tack, Bridles, Halters, Saddle Blankets Diagnosis: Special DTM Media (1-4 weeks)

9 Dermatophytosis

10 Dermatophytosis

11 Dermatophytosis Treatment Scabs and crusts should be removed, lesions cleaned well, clip hair (clean clippers to eliminate spread to other horses) Miconazole Shampoo (Malaseb) Ketaconazole Shampoo Ketaconazole Cream Silver Sulfa Diazene Cream Systemic Anti-fungals (Griseofulvin) in select cases

12 Dermatophilosis (Rain Rot) Actinomycete (Bacteria) Carrier animal, moist environment, abrasions Chronically affected animals are primary source of infection, moisture releases zoospores Mechanical transmission by flies or fomites Fall/Winter most common Dorsal surfaces affected Diagnosis: Cytology, Culture, Biopsy

13 Dematophilosis

14 Dermatophilosis

15 Dermatophilosis Treatment Remove crusts, can be very painful, sedation may be required Clip margins, most important Clean skin with chlorhexidine or betadine scrub Malaseb shampoo, Lime Sulfur Shampoo Systemic Antibiotics SMZ or Penicillin Immune Boosters (ie Eqstim) Use dilute Clorox for equiment or tack NOT THE HORSE! SSD can be used for deep lesions

16 Urticaria (Hives) Immune mediated reaction Food, inhaled, contact (insect, shavings, blanket), injection (insect, vaccines, drugs), Pitting edema, pruritis (small or large) Symptoms not a disease List of possible causes, can make the diagnosis seem ominous Serological testing vs Intradermal testing

17 Urticaria

18 Urticaria Treatment Depends on case: +/- glucocorticoids +/- bathing with oatmeal shampoo if contact +/- antihistamines +/- NSAIDS (Banamine) Can be life threatening

19 Culicoides Gnat Hypersensitivity Puritis! Puritis! Puritis! Breed predisposition: Welsh Ponies, Arabians, Connemaras, Icelandic Horses, QH, Shires, Andalusian, Friesian Seasonal (June- September) Mane, Tail, Ventrum, Face, Legs Alopecia, excoriations, open sores, bleeding Rule out other diseases (cytology, culture, ect) Allergy testing to Prove

20 Culicoides Gnat Hypersensitivity

21 Culicoides Gnat Treatment Fatty Acid Supplement (6-8 wks for effect) ****Boett Blanket: Antihistamines Allergy Shots Garlic? Glucocorticoids (Prednisolone) Topicals: Oatmeal Shampoo, Aloe, Steroids, Scratches Meds, Swat Fans, stall before dusk to mid-morning

22 Culicoides Gnat Hypersensitivity

23 Pemphigus Foliaceous Autoimmune skin disease Autoantibodies are directed against surface proteins of keratinocytes which results in acantholysis (loss of adhesion) Waxing and waning vesiculopustular disorder Vesicles, pustules, crusts, alopecia, epidermal collarettes, scaling Lesions can begin on head or legs and spread to rest of body Depression, poor appetite, weight loss, fever Diagnosis: Cytologies, biopsy, Cultures, Skin scrapings Treatment: Glucocorticoids Prognosis: Poor

24 Pemphigus folliaceous

25 Grease Heel Syndrome (Scratches) Numerous causes for grease heel exist. Infections, allergies, photosensitization, cannon keratosis, parasitic and idiopathic causes have all been associated with grease heel. Pathogenesis for the idiopathic form is thought to be due to an irritant, moisture or poor hygiene.

26 Scratches Syndrome Dermatitis of the lower legs Pruritus and pain may be present. Swelling and erythema that starts on the posterior aspect of the pastern and spreads dorsally and anteriorly. Lesions progress to include crusting, exudation, lichenification and ulceration.

27 Scratches Symptoms If lesions are allowed to progress then exuberant granulation and keloids develop ( grapes ). Lesions tend to be more sever in the hind limbs. Some horses only have 1 limb affected.

28 Scratches Treatment Affected areas should be clipped Cleaned twice daily Topical medications and steroid preparations may be beneficial Scratches Meds twice daily application Most important to keep DRY

29 Papillomas Papillomas are caused by papovaviruses (DNA). Two different viruses are thought to be involved. The presence of the virus in the skin stimulates epithelial proliferation. Verrucous warts usually occur in young animals; aural plaques are usually seen in older animals.

30 Papillomas Lesions consist of squamous verrucous papillomas. These lesions are located on the muzzle, genitalia and/or lower limbs. Verrucous warts usually spontaneously regress within 6 months.

31 Papillomas (Aural Plaques) Skin lesions consist of depigmented papules or plaques which occur in the inner surface of the pinna. The lesions progress to a larger coalescing plaques with adherent scale. No reliable treatment Aural plaques do not spontaneously resolve. Application of insecticides to the area help to prevent irritation of the plaques by feeding flies.

32 Sarcoids Most common causes of locally aggressive, non-metastatic fibroblastic nodular neoplastic lesions in horses, and they account for 35 90% of dermatological neoplasms Bovine papillomavirus (BPV) Areas of trauma or injury or irritation Diagnosis: Visual or Biopsy Surgical excision alone results in 50% recurrence

33 Sarcoids

34 Sarcoids Treatment Chemotherapy injections Chemotherapy beads Cryotherapy Laser removal Xxterra (Herbal) Aldara (Immune Modifier) Acyclovir (Antiviral)

35 Questions?