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Small Ani. Med- Canine cutaneous and mucocutaneous erosive-ulcerative + crusting diseases (Lecture 7)

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wilsbach's version from 2015-11-21 23:49

intro/review

Question Answer
what are the 3 Indications for performing a skin biopsy?(1) Unusual lesions (2) Tumour / suspect neoplasia (3) Non-responsive to therapy
how much normal and how much diseased tissue do you want to take with your skin biopsy?ONLY TAKE BX OF DZ'd tissue!! You are usually taking a small punch biopsy and the pathologist might not be able to see what skin is dz'd and bx healthy tissue....so only dz'd please
which type of lesions are you gonna wanna bx?Always biopsy active (primary) and intact lesions
Canine cutaneous and mucocutaneous erosive-ulcerative / crusting diseases--> what are some general/non-specific clinical signs?Erythema, depigmentation, erosions, ulcerations and crusts. Occasionally, vesicles / pustules are seen. Pruritus is not the main complaint
Canine cutaneous and mucocutaneous erosive-ulcerative / crusting diseases--> is pruritus caused by these?pruritus is NOT the main complaint
Canine cutaneous and mucocutaneous erosive-ulcerative / crusting diseases--> what are the specific areas targeted in these diseases? (3)(1) Nose (planum nasale) (2) Footpads (3) Mucosal membranes (oral, urogenital)
Canine cutaneous and mucocutaneous erosive-ulcerative / crusting diseases--> how do you usually dx these dzs?Usually requires BIOPSY to make a diagnosis
Canine cutaneous and mucocutaneous erosive-ulcerative / crusting diseases--> is this an adult or a juvenile dz?Adults affected (progressive dzs)
Canine cutaneous and mucocutaneous erosive-ulcerative / crusting diseases--> which drugs will these problems be non-responsive to?Non-antibiotic or corticosteroid (anti-inflammatory dosage) responsive
are lesions for (Canine cutaneous and mucocutaneous erosive-ulcerative / crusting diseases) symmetrical or asymmetrical? what kinda lesions are there? where?Symmetrical lesions (erosions, ulcers, pustules, crusts), and Presence of lesions in non-haired skin and MM (nose, footpads, oral, urogenital)
what are the two Autoimmune diseases which have cutaneous/ mucocutaneous erosive-ulcerative / crusting problems?Discoid lupus erythematous (DLE), Pemphigus foliaceus (PF)
what is the Metabolic disease which has cutaneous/ mucocutaneous erosive-ulcerative / crusting problems?Superficial necrolytic dermatitis (NME / hepatocutaneous syndrome)
what is the neoplasia which has cutaneous/ mucocutaneous erosive-ulcerative / crusting problems?Epitheliotrophic T-cell lymphoma (ETCL)
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Pemphigus folicaeus (PF)

Question Answer
what is Pemphigus folicaeusAutoimmune skin disease characterized by formation of subcorneal pustules due to acantholysis
what is acantholysis? What is the result of it?Attack and destruction of intercellular bridges (desmosomes) resulting in intraepithelial blister formation
what is the autoimmune mechanism behind pemphigus folicaeus?IgG autoantibodies against desmosomal proteins
what do the pustules from pemphigus folicaeus contain?Pustules contain acantholytic cells and variable numbers of neutrophils
which desmosome is attacked in dogs?desmocollin-I (Dsc-1) (humans is desmoglein-I (Dsg-1) )
how common is PF?Most common canine autoimmune skin disease
which breeds are predisposed to PF?Akita, Chow Chow (but any breed can be affected)
is it young dogs or adult dogs who get PF?Adult dogs (4-8 years) (but still can affect any age. she mentioned it can affect cats too)
does PF cause pruritus?Pruritus moderate to absent
what dz can PF mimic to confuse you?Can mimic bacterial folliculitis*
Three main clinical presentations (lesions) of PF?(1) Papules, pustules, collarettes, crusts (yellowish); generalized distribution (2) Depigmentation, erosions, ulcers, crusts on planum nasale, dorsal muzzle, pinnae, periocular skin (3) Footpad hyperkeratosis, crusting (A patient can present with 1, 2 or 3 or any combination of the above)
PF can look like things that cause folliculitis...which 3 things cause folliculitis?demodex + bacterial foliculitis + dermatophytosis
PF can be big pustules, what is the other problem that causes large pustules?bacterial infxn (pic is PF)
can cats get PF?yes
what are the lesion distributions for FELINE PF?"stripper dz" because lesions on face, nipples, and nails
how do you dx PF? (2) (what sample sites?)(1) Cytological examination (intact vesicles-pustules, under crusts) to find acantholytic cells (she says she wont just use cytology to dx- need bx too) (2) Multiple biopsies (pustules) for histopathologic examination
what are acantholytic cells? What do they look like?these are keratinocytes which are immature and more superficial than they should be due to the desmosomes being attacked so they are in places they shouldn't be. look like "fried eggs"
what are the three drug types/drugs you give to tx PF?(1) Prednisone or prednisolone (2 mg/kg PO, q 24h) (she said some books will say up to 10, but she says this is too high stick to 2) (2) +/- Azathioprine (1.5-2 mg/kg PO q 24h) (never in cats!!!) (3) Antibiotics for secondary infections
how do you go about GIVING tx for PF? (phases)In two phases: (1) Induction (high-dose daily) 2 weeks (2) Maintenance (low-dose EOD--> every other day/ETD-->??) for life long
which drug can you give to tx PF that you can give to dogs but NOT CATS?Azathioprine
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Discoid Lupus Erythematosus (DLE)

Question Answer
how common is DLE?2nd most common canine autoimmune skin disease
which breeds are prone to getting DLE?Dolicocephalic breeds (Collie, German shepherd)
how does DLE usually present/ look like?Depigmentation and loss of the architecture of nasal planum, erosions, ulcers, crusts.
what is the distribution of DLE lesions?Lesions limited to face (nose, periocular) and rarely to footpads, rarely oral lesions, rarely other MC skin
is DLE seasonal?Worsening with sun exposure (spring, summer)
how do you dx DLE?Clinical signs + cutaneous biopsies
what does DLE look like on histo?characteristic lichenoid band
4 possible tx for DLE?(1) Sun protection; waterproof SPF 45 (2) Topical potent corticosteroids / tacrolimus BID (3) Tetracycline + niacinamide 250 or 500mg/kg PO q 8h (doxycycline / minocycline 5mg/Kg PO BID can substitute tetracycline) (4) Systemic corticosteroids (prednisone 2 mg/kg PO q 24h)
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Superficial necrolytic dermatitis (SND)

Question Answer
Superficial necrolytic dermatitis can be aka... (2)Hepatocutaneous syndrome, necrolytic migratory erythema
how common is SND?Uncommon
why does SND happen?cutaneous syndrome due to metabolic disorder; often liver disease, rarely pancreatic disease---> Inability to synthesize certain amino acids
who is predisposed to SND?Older, male, small breed dogs predisposed
what are the clinical signs of SND?Erythema, erosions, and heavy crusts on pressure points, footpads, multifocal generalized on trunk. Severe crusting and ulceration of footpads is very characteristic**
what is a VERY characteristic clinical sign of SND?Severe crusting and ulceration of footpads is very characteristic**
Does SND cause pruritus?usually NOT, unless there is a 2* Malassezia infection
which two dzs can cause elbow calluses like this, how can you differentiate them?well...obv one is SND. The other one is sarcoptes but the dog would be ITCHY was sarcoptes and not with SND
can cats get SND?yes....extremely rarely
4 ways to dx SND?(1) CBC, serum chemistry (2) Abdominal US (3) Skin biopsy & histopathology (4) Amino acid levels (UC Davis)
what does CBC, serum chemistry look like for a dog with SND?Normochromic, normocytic, non-regen anemia, Hyperglycemia, Elevations in ALP, AST; Hypoalbuminemia, Increased postprandial bile acids
what will amino acid levels be like with SND?Hypoaminoacidemia (makes sense, dz is bc liver problem--> cant make certain amino acids)
what two things are you gonna look at with abdominal U/S, and what will you see in SND?(1) Liver disease: “honeycomb” or “Swiss cheese” pattern (2) Pancreatic disease: rare, tumor detected on US
what does SND look like on histopath?Very specific changes!!!!: (1) Epidermal hyperplasia with marked parakeratosis (4 diamonds) (2) Vacuolar degeneration in middle layer of epidermis (star) (3) Moderate inflammatory infiltrate in dermis (one diamond)
what does the "red" mean in the red white and blue histo pattern? where is it?Red at the most superficial point--> This is the epi hyperplasia with parakeratosis (Parakeratosis is a mode of keratinization characterized by the retention of nuclei in the stratum corneum)
what does the "white" mean in the red white and blue histo pattern? where is it?white in the middle of red and blue--> this is Vacuolar degeneration
what does the "blue" mean in the red white and blue histo pattern? where is it?most deep layer- these are inflammatory cells
what is the treatment for SND, what should you know about it?SND is a marker for a serious internal disease with a short survival time; poor prognosis (aprx 6 months from the time of diagnosis). If glucagonoma, surgery is indicated. Amino acid solutions can be given IV as supportive therapy to patients with liver disease and hypoaminoacidemia
when is sx indicated with SND?only indicated if there is a glucagonoma
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Epitheliotrophic T-cell lymphoma (ETCL) + summary

Question Answer
what is ETCL a neoplasia of, what is going on with it?Neoplasia of T lymphocytes that infiltrate the epidermis & mucosal epithelium (epitheliotropism)
age disposition for ETCL?old dogs
what are lesions of ETCL?Ulcerative stomatitis, nasal depigmentation, erythematous plaques, scales, variable pruritus, nodules, erosions, ulcers (in pic you can see hypopigmentation and loss of architecure, ie smooth not cobblestone, on nose)
how do you dx ETCL?Diagnosis by multiple biopsies and histopathology
what are the neoplastic lymphocytes doing, and what problems do they cause?Neoplastic lymphocytes invading the epidermis, often with destruction of hair follicles and adnexae
what does histopath look like for ETCL?see tons of neoplastic lymphocytes invading the skin (all those purple dots are lymphocytes)
how do you tx ETCL?No effective treatment (Lomustine, prednisone)
prog of ETCL?Poor prognosis...about 6mo at time of dx
(1) Nose erosions, ulcers, depigmentation (2) Mucosal erosions, ulcerations (3) Footpad hyperkeratosis, fissures, ulcers--> does DLE have any, some, or all of these?1 and 2
(1) Nose erosions, ulcers, depigmentation (2) Mucosal erosions, ulcerations (3) Footpad hyperkeratosis, fissures, ulcers--> does PF have any, some, or all of these?1 and 3
(1) Nose erosions, ulcers, depigmentation (2) Mucosal erosions, ulcerations (3) Footpad hyperkeratosis, fissures, ulcers--> does SND have any, some, or all of these?3
(1) Nose erosions, ulcers, depigmentation (2) Mucosal erosions, ulcerations (3) Footpad hyperkeratosis, fissures, ulcers--> does ETCL have any, some, or all of these?1, 2, and 3
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