3.22.1.14 Pemphigus species comparison TR15.00.pdf

Pemphigus foliaceus (PF) - species comparison about Dog Cat Horse Goat Signalment Marked breed predisposition (e.g. Akitas, Chows and dachshunds) Age 1-16 years (median 6 years) No sex predisposition No breed predisposition (domestic short-haired cats in one study) Age 1–17 years (median 6 yea...

Pemphigus foliaceus (PF) - species comparison about Dog Cat Horse Goat Signalment Marked breed predisposition (e.g. Akitas, Chows and dachshunds) Age 1-16 years (median 6 years) No sex predisposition No breed predisposition (domestic short-haired cats in one study) Age 1–17 years (median 6 years) No sex predisposition Appaloosa predisposed in one study Rare – signalment poorly defined Age ½ – 25 (no accepted median) No sex predisposition History Acute onset of pustules, erosions and crusts Fever and anorexia may be present Acute onset of crusts and erosions (pustules rarely seen) Fever and anorexia may be present Acute onset, often with urticaria Acute onset, but usually presented preceding the pustules and crusts. in generalised form Crusts are the predominant signs Limb and ventral abdominal oedema may be reported Picture Clinical signs (general) Clinical signs of PF appear to be similar across domestic animal species Superficial pustules develop rapidly into erosions and crusts which predominate The pustules of PF are usually large and may have erythematous, irregular borders. Several hair follicles can be involved, and hairs may be seen protruding from the pustules in several places, compared to the lesions of bacterial folliculitis where only a single follicle is involved. NOTE: There is a some detail here that is most relevant to the fourth and final years. Use this table to remind you about and reinforce the information in the workshop. The most important facts to pick out are the common themes between the species. University of Nottingham 1 Clinical signs Initial lesions: face (principally dorsal muzzle, planum nasale, periocular skin and ears). 16% of cases have lesions only affecting the face and head. Bilateral and symmetrical. Occasionally a generalised distribution at onset, but most more slowly develop signs affecting the whole body (66%) with the trunk being most affected. Other regions affected include the footpads (33%) and can be the sole sign. Mucosal lesions are very rare Initial lesions: erosions and yellowish crusts on the face, ears and feet. Bilateral and symmetrical. Footpad or ungual folds lesions are common. The purulent paronychia is quite distinct / pathognomonic. Lesions around the nipples are common. Generalised disease is uncommon and feline PF is usually mild and localised. Pruritus variable, often pinnal pruritus is observed Initial lesions: crusts affecting the face and neck with development of truncal and involvement of the feet and legs signs over 1-3 months Ventral and limb oedema is seen in many horses with PF and systemic signs, such as depression and lethargy are reported in up to 50% of cases. PF lesions are occasionally painful (particularly coronary band lesions) and can be pruritic In goats, pustules are rarely noted, and crust, scale and alopecia predominate The face, ventral abdomen, limbs, perineum and tail. In female animals, lesions may affect the udder and teats. Pruritus is common in the authors experience Pruritus is present in 25–50% Target antigen Desmocollin-1 Desmoglein-1 postulated but not confirmed Differential diagnoses (common) Superficial pyoderma If sign localised to the face and feet, cutaneous lupus Severe zinc responsive dermatosis Superficial pyoderma Notoedres sp (not thought to be present in UK) Norwegian Scabies (Sarcoptes scabei var canis) presenting in immunosuppressed cats) Diagnosis Rule out completing differential diagnoses, cytology and histopathology Cytology Relatively non-degenerative neutrophilic inflammation with rounded distinct acantholytic keratinocytes Histopathology In dogs, cats, horses and goats with PF, histological examination of lesional skin reveals similar findings. Lesions affect the surface epithelium and the lumen of follicular infundibulum Pustules are large and span multiple follicular units Early: Vesicles with acantholytic keratinocytes and scant neutrophils Later: Intragranular or subcorneal pustules with isolated and/or clustered acantholytic keratinocytes (neutrophils predominate, but eosinophils are not uncommon) 2 Superficial pyoderma Dermatophilosis Chorioptes infestation Other causes of scale and pastern dermatitis Coronary band disorders University of Nottingham Zinc deficiency Chorioptes infestation Scabies infestation Treatment options Prognosis Immunosuppressive steroids (2-4 mg/kg prednisolone in divided doses) for 10-14 days, with the addition of azathioprine or chlorambucil if a poor response at 10 days High-dose intermittent steroid therapy (10mg/kg prednisolone every 3-4 days) after induction has recently been advocated. Immunosuppressive steroids (3-5 As in dogs and cats PF can be treated successfully in horses and goats with mg/kg prednisolone in divided dos- either prednisolone or dexamethasone alone or in combination es) for 10-14 days, with the addition with aurothioglucose (gold salts). of chlorambucil if a poor response at 10 days Study 1: 31 dogs. 71% survival at 1 year (13% euthanised due to poor response or relapse) Study 2: 88 dogs. 52% complete remission, 35% partial remission and 13% euthanised. 2% came off treatment without recurrence. Often costs and treatment side effects are as important as treatment failure in the reasons for euthanasia Study 1: 100% of cats achieved remission on triamcinolone alone and 62% on prednisone. It is likely that prednisolone would be more successful, but this is not reported. 82% achieved remission on prednisone and chlorambucil. 13% of cats were euthanised. The addition of chlorambucil is rarely needed Limited data: In one study 38% were euthanized for lack of response or development of steroid-induced acute laminitis. 36% remained in remission for more than one year after treatment was discontinued. No evidence-based data available In published studies the commonly held belief that equine PF is easier to treat in young horses is not substantiated. University of Nottingham 3