Dermatology: Skin Lesion Recognition Flashcards
Primary Lesions
What is a papule
Small, solid elevation up to ≤1 cm in diameter. Due to infiltration of inflammatory cells & edema
Flea bites, SF bacterial folliculitis
Primary Lesions
Pustule
Similar to a papule, but filled with purulent material. Cane be intra-epidermal, follicular or non-follicular
Primary Lesions
Characteristics of Early versus Late Pemphigus foliaceus lesions
Primary Lesions
What is a Plaque?
Primary Lesions
What does a wheal (hive) lesion consist of? Characteristics?
Edema. Appear & disappear within mins-hours
Type of hypersensitivity rxn // immunoglobulin for allergic reactions?
Type I // IgE
Primary Lesions
What is a Macule?
Flat, circumscribed skin discoloration, <1 cm in diameter. Lacks surface elevation or depression.
Primary Lesions
What is a patch?
Primary Lesions
What is a vesicle?
equivalent to chicken pox in humans.
vetmed: mostly farm animals (viral diseases); autoimmune diseases in cats/dogs
Primary Lesions
Nodule
- sharply circumscribed, elevated lesion >1cm in diameter
- extends into the dermis
neoplasis, deep infection, immune-mediated
Primary Lesions
Cyst
- nodule that contains fluid or semi-solid material
- follicular cyst, indundibular cyst, apocrine cyst
Primary Lesions
Bulla
Secondary Lesions
Erosion – typically superficial
Secondary Lesions
Ulcer – deeper than they look. Can cause capillary bleeding (compared to eroisions)
Secondary Lesions
Excoriation
Secondary Lesions
Fissure
Secondary Lesions
What is the definition of a scar?
A formation of new, connective fibrous tissue (fibrosis). Implies prior dermo-epidermal damge (injury that extended beyond the basement membrane).
Ulcer = prior injury; trauma
Secondary Lesions
What is an epidermal collarette?
Circular rings of scales with erythema.
Two types: Non-expanding & Expanding
Erythema: superficial reddening of the skin, usually in patches, as a result of injury or irritation causing dilatation of the blood capillaries.
Secondary Lesions
Non-expanding Epidermal Collarette
“Footprint” of a ruptures pustule.
SF pyoderma; sterile pustular dermatosis
Secondary Lesions
Expanding Epidermal Collarette
Secondary Lesions
Definition of Lichenification
Marked thickening of all 3 epidermal layers caused by chronic rubbing or scratching
example: canine atopic dermatitis
Secondary Lesions
How does hyperkeratosis differ from lichenification?
increased thickness in the stratum corneum (horny layer) only!
Primary or Secondary Lesions
Spontaneous vs Self-Induced Alopecia
Spontaneous: hair easily epilates, sharp margin, tip of hair unaffected; less common than self-inflicted
Primary or Secondary Lesions
Diagnostic method used for this alpopecic patient
Trichogram
Trichogram represents a semi‐invasive technique for the evaluation of patients with hair loss that allows the microscopic examination of hairs plucked from the scalp and provides information about the state of the proximal end of the hair shaft and the distal end.
Primary or Secondary Lesions
What causes scaling?
Accumulation of loose fragments of the stratum corneum.
- either caused by excessive production of daughter s=cells by basal cells, or by disorder in glanduar (sebaceous) secretions
Scaling lesion can be 1º or 2º
Primary or Secondary Lesions
Difference b/w crust and a scale
Scale: stratum corneum
Crust: stratum corneum + cellular debris, dried exudate, inflammatory cells or blood
Primary or Secondary Lesions
Exampls of primary and secondary lesions of crust
1º: zinc-responsive dermatosis, hepatocutaneous syndrome
2º: pyoderma, pruitus (excoriation), pemphigus foliaceus
Primary or Secondary Lesions
What is a Follicular Cast? What is it typically associated with?
Primary or Secondary Lesions
What is a comedo (plural = comedones)? Primary versus secondary comedo lesions?
Lesion Colors
Erythema
Redness of the skin (rash); caused by congestion (vasodilation) in of the blood vessels in the dermis.
Blanches with pressure.
Lesion Colors
Petechia/Purpura
Dark red to purplish discoloration.
Caused by extravasation of RBC into dermis (hemorrhage). NO BLANCHING OCCURS with PRESSURE!
Example = vasculitis; leaky blood vessels
Lesion Colors
Hypopigmentation
Lighter-than-normal skin; vitiligo, albinism
Lesion Colors
Hyperpigmentation
Darker-than-normal skin
Hypothyroidism, post-inflammatory
