Autoimmune Skin Diseases (Marsella)

Question 1

Pemphigus complex

Answer 1

• Antibodies produced against protein (desmogleins) responsible for intercellular adhesion
• Type II hypersensitivity
• Detachement of cells from each other (acantholytic cells)

Question 2

Pemphigus foliaceus location of action

Answer 2

Antibodies target antigens in the upper part of the epidermis (right below the stratum corneum)

Question 3

Pemphigus foliaceus predilections

Answer 3

• Dogs, cats, horses, goats
• Chow-chow, Collie, Akita
• Middle-aged to old animals

Question 4

Pemphigus foliaceus clinical signs

Answer 4

• Primary lesion: pustule
• Crusting & scaling
• Distribution: pinnae, face, bridge of nose, hyperkeratosis of footpads, nailbed (cats)
• Cat distribution (“stripper’s disease”): face, perinipple, nail beds

Question 5

Pemphigus foliaceus diagnosis

Answer 5

• Cytology from pustule
• Histopath
• Biopsy new lesions (when off steroids)
• R/O pyoderma & demodex

Question 6

Pemphigus foliaceus therapy

Answer 6

• Long term w/ potential serious side effects
• High doses of corticosteroids
• Azathioprine (dogs)
• Chlorambucil (cats)
• Gold

Question 7

Pemphigus erythematosus predilections

Answer 7

• Collies
• German shepherds

Question 8

Pemphigus erythematosus pathogenesis

Answer 8

• Cross over between pemphigus & lupus
• Milder than PF
• Antibodies
  
  • Intercellular spaces of epidermis (pemphigus)
  • Basement membrane (lupus)

Question 9

Pemphigus erythematosus clinical signs

Answer 9

• Pustular dermatitis - face & ears
• Nasal depigmentation
• Aggravated by UV light

Question 10

Pemphigus erythematosus diagnosis

Answer 10

• Cytology
• Histopath
• ANA test (antinuclear antibody) is negative

Question 11

Pemphigus erythematosus therapy

Answer 11

• Mild
  
  • Topical steroids or tacrolimus
  • Sunscreen
• Severe
  
  • immunosuppressive therapy

Question 12

Pemphigus vulgaris predilections

Answer 12

• Most common type in humans
• Rare in animals, but usually older animals

Question 13

Pemphigus vulgaris location of action

Answer 13

Acantholysis in lower epidermis

Question 14

Pemphigus vulgaris clinical signs

Answer 14

• Primary lesion: bulla
• Ulcerations & erosions
• Distribution: oral cavity, mucocutaneous junctions, nail beds (sloughing), axillae, groin
• Lethargy, fever, anorexia
• 2º infections

Question 15

Pemphigus vulgaris diagnosis

Answer 15

• Histopath
  
  • Biopsy fresh lesions
• R/O more common diseases

Question 16

Pemphigus vulgaris therapy and prognosis

Answer 16

• Immunosuppression - require high dose to stay in remission
• Prognosis guarded to poor, fatal without therapy

Question 17

Pemphigus vegetans

Answer 17

• Very rare
• Mild form of pemphigus vulgaris
• Proliferative lesions
• Scaling, crusting of axillae and groin
• Diagnose & treat same as pemphigus foliaceus

Question 18

Discoid lupus erythematosus predilections

Answer 18

• Collie
• German shepherd

Question 19

Discoid lupus erythematosus pathogenesis

Answer 19

• Benign form of lupus
• Sunlight triggers expression of new antigens
• Produciton of antibodies
  
  • Deposition in basement membrane
  • Type II cytotoxic reaction

Question 20

Discoid lupus erythematosus clinical signs

Answer 20

• Nose
  
  • Depigmentation
  • Loss of normal appearance
  • Erosions & ulcerations
• Pinnae, eyelids, lips, footpads (rare)

Question 21

Discoid lupus erythematosus diagnosis

Answer 21

• Histopathology
• Immunofluorescence
• ANA test (antinuclear antibody) - negative

Question 22

Discoid lupus erythematosus therapy

Answer 22

• Topical steroids or tacrolimus
• Sunscreen, vit. E
• Systemic steroids (low dose) or tetracycline/niacinamide

Question 23

Systemic lypus erythematosus pathogenesis

Answer 23

Antibodies produced against different antigens (RBCs, platelets, nuclear antigens…)

Question 24

Dermatological signs of systemic lupus erythematosus

Answer 24

• Seberrhea
• Vasculitis - necrosis of pinnae and tip of tail, crusting and ulceration of footpads
• Nasal depigmentation & ulceration
• Mucocutaneous bullous disease
• Panniculitis

Question 25

Systemic lupus erythematosus diagnosis

Answer 25

* **Presence of multisystemic dz** * CBC, chem, UA * Anemia, thrombocytopenia, proteinuria * ANA test (antinuclear antibody test): 90% * Suggestive histopath and immunofluorescence

Question 26

Sysemic lupus erythematosus therapy

Answer 26

* Immunosuppressive drugs (high dose) * Azathioprine * Chlorambucil * Gold contraindicated due to renal complications

Question 27

Bullous pemphigoid predilections

Answer 27

* Old animals * Collies * Dobermans

Question 28

Bullous pemphigoid pathology

Answer 28

Antibodies produced against basement membrane (not a true pemphigus b/c no acantholytic cells and it acts in the basement membrane)

Question 29

Bullous pemphigoid clinical signs

Answer 29

* Primary lesion: bulla * Ulcerations * Fever & anorexia * Distribution: **oral cavity**, axillae, groin, mucocutaneous junctions, nail beds * Paronichia (infection) , sloughing of nailes

Question 30

Bullous pemphigoid diagnosis & therapy

Answer 30

* Histopath * Immunofluorescence * Immunohistochemistry * Tx same as pemphigus foliaceus

Question 31

Erythema multiforme pathogenesis

Answer 31

* Immune mediated **syndrome** * **2º to drugs or infections** (cephalosporins, TMP-sulfa, levamisole, gold) * Acute, self-limiting

Question 32

Erythema multiforme clinical signs

Answer 32

* **Target lesions** - peripheral erythema w/ central clearing * Macules * Plaques

Question 33

Erythema multiforme diagnosis

Answer 33

* Suggestive history and clinical signs * Histopathology - biopsy epidermis, not ulcer

Question 34

Erythema multiforme therapy

Answer 34

* ID & tx underlying cause * Supportive therapy * Abx for 2º infection * Steroids (controversial)

Question 35

Toxic epidermal necrosis (general info)

Answer 35

* Severe cutaneous eruption * Systemically ill - fever, lethargy * Full thickness necrosis and sloughing * Mucosal ulcerations * Arthralgia (usually induced by drugs, like Hartz products)

Question 36

Toxic epidermal necrosis diagnosis

Answer 36

Histopath of early lesions

Question 37

Toxic epidermal necrosis therapy & prognosis

Answer 37

* ID & tx underlying cause * Supportive (fluids, abx) * NO steroids * Poor prognosis (electrolyte loss, 2º infections)

Question 38

Mycosis fungoides pathogenesis

Answer 38

Cutaneous lymphoma (T cells) CANCER (not a damn fungus)

Question 39

Mycosis fungoides clinical signs

Answer 39

* Erythema, pruritis, seborrhea * Depigmentation & ulcerations of mucus membranes & nose * Stomatitis & oral ulcerations (animal stops eating) * Plaques & nodules

Question 40

Necrolytic migratory erythema (general info)

Answer 40

* AKA: hepato-cutaneous syndrome, glucagonoma syndrome, superficial necrolytis dermatitis * Old dogs * Associated w/ liver dz, glucagonoma, diabetes mellitus, Cushing's

Question 41

Necrolytic migratory erythema pathogenesis

Answer 41

* Metabolic defect - nutritional deficiency at epidermis → skin necrosis * Aminoacids * Zinc * Fatty acids * Cutaneous lesions may occur months before onset of systemic dz

Question 42

Necrolytic migratory erythema clinical signs

Answer 42

* Erythema, ulcerations, crusting * Distribution: pinnae, muzzle, footpads, genitalia * 2º bacterial & yeast infections

Question 43

Necrolytic migratory erythema diagnosis

Answer 43

* Histopath * "Red, white, and blue" * Blue - hyperplasia of basal cell layer * White - cellular edema in middle epidermis * Red - hyperkeratotic parakeratosis

Question 44

Necrolytic migratory erythema therapy & prognosis

Answer 44

* ID & correct underlying dz * Treat 2º infections * Aminoacid, zinc, fatty acid supplement * NO glucocorticoids * Poor prognosis (death in 6 mos after onset of cutaneous lesions)