Erosions & Ulcers Flashcards
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)
What are the 2 most common traumatic causes of erosions and/or ulcers?
Pyotraumatic dermatitis & Intertrigo
Pyotraumatic dermatitis = “hot spots”
Top 4 differential etiologies for Pyotraumatic dermatitis
Pyotraumatic dermatitis
Potential etiologies:
1. Allergic skin disease
2. Otitis externa
3. Ectoparasites
4. Matted hair
What is intertrigo’s common name?
Skin fold pyoderma
Lip fold, facial fold, tail fold
Pathogenesis of Intertrigo?
Is an anatomical problem!
Sequela: eroision, ulceration
What is an important aspect of treating skin fold pyoderma?
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
Superficial vasculitis lesions sequela vs Deep vasculitis sequela?
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.
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)
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
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
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
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
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
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
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?
called “discoid” b/c in humans, this type causes coin/disc-shaped 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
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
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
“Serpiginous” = having a wavy margin
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:
Generalized scaling + thinning of hair // alopecia
Autoimmune/immune-mediated
Uveodermatological syndrome (VKH)
- pathogenesis
- Cytotoxic T lymphocytes (CD8+) attack the pigment cells (melanocytes) of the skin (mostly facial skin) and eyes!
- Neighboring basal cells also get affected
- Inflammation -» Erosion / Ulceration
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
Dermis = strongest part of skin
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)
