Erosions & Ulcers Flashcards by Kate Karlen

Erosion vs Ulcer

Erosion: partial loss of epidermis with NO penetration of basement membrane, and heals without scarring

Ulcer: full loss of epidermis that penetrates/extends beyond the basement membrane, and heals with scarring (chronic cases)

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What are the 2 most common traumatic causes of erosions and/or ulcers?

Pyotraumatic dermatitis & Intertrigo

Pyotraumatic dermatitis = “hot spots”

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Top 4 differential etiologies for Pyotraumatic dermatitis

Pyotraumatic dermatitis

Potential etiologies:
1. Allergic skin disease
2. Otitis externa
3. Ectoparasites
4. Matted hair

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What is intertrigo’s common name?

Skin fold pyoderma

Lip fold, facial fold, tail fold

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Pathogenesis of Intertrigo?

Is an anatomical problem!
Sequela: eroision, ulceration

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What is an important aspect of treating skin fold pyoderma?

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What is the common distribution of vasculitis?

Vasculitis is NOT a condition! It is a clinical sign of an underlying condition!

Extremities (intitially), but can become generalized.
- paws/paw pads
- tail
- ear tips/margins
- nose

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Superficial vasculitis lesions sequela vs Deep vasculitis sequela?

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What procedure can be used to distinguish cutaneous erythema from petechial hemorrhage?

Diascopy

Diascopy is a refinement in which a piece of clear glass or plastic is pressed against the skin while the observer looks directly at the lesion under pressure.

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Why must you avoid obtaining a skin biopsy from the center of an ulcer when sampling for vasculitis diagnosis?

b/c trying to capture lesion that still has evidence of inflammation of the vessel (ulcer = end-stage lesion)

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Necrolytic Migratory Erythema is a reflection of what?

aka hepatic cutaneous syndrome

cutaneous manifestation of systemic metabolic disease ->
- Hyperkeratosis, crusting, fissures, ulcerations of footpads
- Erosions & crusts of the Muco-Cutaneous Junctions (eyes, nose, mouth, anus), Pressure Points on Limbs, and Areas of Friction (axillae, groin, scrotum)

non-derm signs: lethargy, weakness, PU/PD

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What is the predicted pathogenesis of necrolytic migrated erythema?

Low serum amino acids

Commonly seen in older dogs

Chronic hepatic disease = 80% of cases. Others: phenobatbital-associated disease, pancreatic glucagonoma, atrophic enteritis

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Necrolytic Migratory Erythema?
- what to avoid for biopsy?
- if seen, what does liver on abd u/s show?

An entirely eroded or ulcerated lesion
a honeycomb / swiss cheese pattern MAY be seen

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Prognosis and treatment of Necrolytic Migratory Erythema?

Prognosis is poor (6-12 months)
Therapy = palliative and based on underlying cause!
- For-life (q3-4 weeks) intravenous amino acid infusion = most effective

Other Txs: high-quality protein diet, zinc supplementation, essential fatty acids, treat the 2º infections

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Squamous Cell Carcinoma & Cutaneous Lymphoma

Describe the mechanism of Neoplasia & Tumor Hypoxia => erosions and ulcerations

Neoplasia & Tumor Hypoxia: Rapidly growing tumor cells exceed how much the blood vessels can supply to them -> tumor hypoxia -> ischemic necrosis -> erosions / ulcers

Small tumor: growth does not exceed and is successful at growing

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Squamous Cell Carcinoma & Cutaneous Lymphoma

Describe the mechanism of Neoplasia & Cytotoxicity => erosions & ulcerations

Release of toxic cytokines => epidermis undergoes necrosis

Cytokines are small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells.

Squamous Cell Carcinoma & Cutaneous Lymphoma

Pathogenesis of SCC in cats?

1.Chronic exposure to UV light
White cats > colored cats

Other causes = certain strains of papilloma viruses

Only susceptible cats develop SCC

Squamous Cell Carcinoma & Cutaneous Lymphoma

SCC is the most common epithelial cancer in dogs/cats. What are its lesions?

Localized, proliferative tumors that lead to ulceration & cause tissue destruction

SCC = locally invasive & slow to metastasize

Squamous Cell Carcinoma & Cutaneous Lymphoma

What is the most effective tx of SCC?

Surgical excision

Squamous Cell Carcinoma & Cutaneous Lymphoma

To diagnose SCC or Cutaneous Lymphoma, why should you never biopsy from an entirely ulcerated lesion?

NO EPIDERMIS LEFT IN AN ULCER! -> diagnosis requires the cells of living, affected epidermis

Squamous Cell Carcinoma & Cutaneous Lymphoma

Prognosis and treatment for Cutaneous Lymphoma?

autoimmune/immune-mediated

Pathogenesis of Cutaneous Lupus Erythematosus

Attacks the basal cells of the epidermis -> triggers antigen release / immune system -> CD8+ cells release cytotoxic granules -> cause the basal cells to under apoptosis -> -> scarring (erosions & ulcerations)

UV light may be involved in pathogenesis, as well!

CD8+ = cytotoxic T lymphocytes

autoimmune-immune-mediated

Discoid Cutaneous Lupus Erythematosus (Canine Facial DLE): where are the lesions?

Only the nasal planum is affected (does NOT go up to the nose bridge!)

Cutaneous Lupus Erythematosus

Top differential with canine facial DLE?

Mucous Membrane pemphigoid

# Cutaneous Lupus Erythematosus Correct biopsy for Cutaneous Lupus Erythematosus?

**Edge** of erosion/ulcer (30% ulcer, 70% normal-appearing tissue) in order to obtain living basal cells! - *for both Discoid & Mucocutaneous forms*

# Cutaneous Lupus Erythematosus How to treat mild vs refractory cases of Canine Facial DLE?

**Mild**: Doxy or Minocycline (5mg/kg q12) with Miacinamide (250-500mg q8-12h), +/- topical glucocorticoids or Tacrolimus Ointment 0.1% **Refractory**: cyclosporine (10mg/kg/day)

# Cutaneous Lupus Erythematosus **Mucocutaneous** Lupus Erythematosus (**MCLE**): breed predisposition and lesion sites?

- **Breed predisposition**: German Shepherds - **Location of esions**: @ Mucocutaneous junctions (anogenital > perioral > periocular > nose)

# Cutaneous Lupus Erythematosus How to differentiate **MCLE** from **mucocutaneous pyoderma**?

Mucocutaneous Pyoderma does **not affect anogential region**- higher tendency for nose & periocular. Erosions are also *less* extensive, and there is complete response to abx therapy

# Cutaneous Lupus Erythematosus What breeds are vulnerable to **Vesicular** cutaneous lupus erythematosus (**VCLE**)? Shape of lesions / locations?

Shetland sheepdog; collies - Lesions = annular, polycyclic or serpiginous-shaped in axillae, groin, concave pinnae ## Footnote "Serpiginous" = having a wavy margin

# Cutaneous Lupus Erythematosus Why should you avoid use of glucocorticoids in treating MCLE?

can shorten time to disease remission

# Cutaneous Lupus Erythematosus **Exfoliative** Cutaneous Lupus Erythematosus (ECLE) = predisposed breeds? How does ECLE **differ** from the other forms?

- GSPs, Vizslas - Differs b/c manifests as **cutaneous AND systemic signs**: ## Footnote **Generalized scaling + thinning of hair // alopecia**

# Autoimmune/immune-mediated **Uveodermatological syndrome** (VKH) - pathogenesis

1. Cytotoxic T lymphocytes (CD8+) attack the pigment cells (**melanocytes**) of the **skin** (mostly *facial skin*) and **eyes**! 2. Neighboring basal cells also get affected 3. **Inflammation ->> Erosion / Ulceration**

# autoimmune/immune-mediated treatment of VKH

aggressive glucocorticoid treatment

# Autoimmune-immune-mediated *Autoimmune Subepidermal Blistering Dermatoses* (**AISBD**): - Pathogenesis - Most common type / species - Lesion sites

Circulating antibodies attack the **basement membrane zone** -> epidermis loses its anchoring to the dermis -> sub-epidermal **vesiculation or clefts** - Mucous Membrane Pemphigoid (**MMP**) - Dogs! **Lesions**: - vesicles, ulcers - mucocutaneous junctions; skin (distant from these junctions) | Clear fluid, little-to-no inflamm. neuts ## Footnote Dermis = strongest part of skin

Treatment of **Canine AISBD** (*Autoimmune Subepidermal Blistering Dermatoses*)

**Rare disease,** but the condition is **chronic & often relapsing** - little info on proper tx / outcome!

# Autoimmune/immune-mediated What condition is this?

**Pemphigus vulgaris** -- **deepest layer of epidermis attacked!** vesicles rupture -> painful ulcers @ nose, lips & oral cavity

What ***histogical feature*** of Pemphigus vulgaris differentiates it from other autoimmune/immune-mediated erosion/ulcerative skin conditions?

Epidermal cleft due to **acantholytic keratinocytes** (acantholysis = loss of adhesion b/w keratinocytes)