Skin disorders and ulcers Flashcards
Outline the pathophysiology of pemphigus vulgaris
Type II hypersensitivity reaction
IgG antibodies against desmoglein-1 and/or desmoglein-3 (component of desmosomes, which connect keratinocytes in the stratum spinosum)
Potentially fatal, seen in older adults commonly
Gross morphology of pemphigus vulgaris
Flaccid intraepidermal bullae caused by acantholysis (separation of keratinocytes, “row of tombstones” on H&E stain)
Oral mucosa is involved
Nikolsky sign ⊕
immunofluorescence of pemphigus vulgaris
Reticular pattern around epidermal cells
Pathophysiology of bullous pemphigoid
Less severe than pemphigus vulgaris
Most commonly seen in older adults
Type II hypersensitivity reaction.
IgG antibodies against hemidesmosomes (epidermal basement membrane; antibodies are “bullow” the epidermis)
Gross morphology of bullous pemphigoid
Tense blisters containing eosinophils; oral mucosa spared
Nikolsky sign ⊝
Immunofluorescence of bullous pemphigoid
Linear pattern at epidermal-dermal junction
Define Epidermolysis bullosa simplex
AD defect in keratin filament assembly = cytoskeleton disruption leading to epithelial fragility
Presentation and course of epidermolysis bullosa simplex and what a skin biopsy would show
Presents early in life with friction-induced skin blistering that primarily affects palms and soles
Heals without scarring
Skin biopsy: intraepidermal cleavage
Dermatitis herpetiformis definition
Pruritic papules, vesicles, and bullae (often found on elbows, knees, buttocks)
Deposits of IgA at tips of dermal papillae
Association and tx of dermatitis herpetiformis
Associated with celiac disease
Treatment: dapsone, gluten-free diet
Erythema multiforme associations and presentation
Associated with infections (eg, Mycoplasma pneumoniae, HSV), drugs (eg, sulfa drugs, β-lactams, phenytoin)
Presents with multiple types of lesions—macules, papules, vesicles, target lesions (look like targets with multiple rings and dusky center showing epithelial disruption)
Characteristics of SJS
Characterized by fever, bullae formation and necrosis, sloughing of skin at dermal-epidermal junction (⊕ Nikolsky), high mortality rate
What is involved in SJS and associated with a reaction to what
Targetoid skin lesions may appear, as seen in erythema multiforme
Usually associated with adverse drug reaction
Toxic epidermal necrolysis definition
More severe form of SJS involving > 30% body surface area
10–30% involvement denotes SJS-TEN
What is the etiology and location of venous ulcers
Chronic venous insufficiency; most common ulcer type
Gaiter area (ankle to midcalf), typically over malleoli
Appearance and pain in venous ulcers
Irregular border, shallow, exudative
Mild to moderate pain
Associated signs of venous ulcers
Telangiectasias, varicose veins, edema, stasis dermatitis (erythematous eczematous patches)
Etiology & location of arterial ulcers
Peripheral artery disease (eg, atherosclerotic stenosis)
Distal toes, anterior shin, pressure points
Appearance & pain of arterial ulcers
Symmetric with well-defined punched-out appearance
Severe pain
Associated signs in arterial ulcers
Signs of arterial insufficiency including cold, pale, atrophic skin with hair loss and nail dystrophy, absent pulse
Etiology & location of neuropathic ulcers
Peripheral neuropathy (eg, diabetic foot)
Bony prominences (eg, metatarsal heads, heel)
Appearance & pain in neuropathic ulcers
Hyperkeratotic edge with undermined borders
no pain
Associated signs in neuropathic ulcers
Claw toes, Charcot joints, absent reflexes
Acanthosis nigricans definition & association
Epidermal hyperplasia causing symmetric, hyperpigmented thickening of skin, especially in axilla or on neck
Associated with insulin resistance (eg, diabetes, obesity, Cushing syndrome, PCOS), visceral malignancy (eg, gastric adenocarcinoma)
Actinic keratosis definition and risk
Premalignant lesions caused by sun exposure
Small, rough, erythematous or brownish papules or plaques
Risk of squamous cell carcinoma is proportional to degree of epithelial dysplasia
Erythema nodosum definition & causes
Painful, raised inflammatory lesions of subcutaneous fat (panniculitis), usually on anterior shins
Often idiopathic, but can be associated with sarcoidosis, coccidioidomycosis, histoplasmosis, TB, streptococcal infections, leprosy, IBD
Ichthyosis vulgaris definition & what ages do they manifest
Disorder of keratinization resulting in diffuse scaling of the skin, most commonly on the extensor side of extremities and the trunk
Manifests in infancy or early childhood
Define lichen planus
6 P’s: Pruritic, purple, polygonal planar papules and plaques
Mucosal involvement manifests as Wickham striae (reticular white lines) and hypergranulosis
Infiltrate and associations of lichen planus
Sawtooth infiltrate of lymphocytes at dermal-epidermal junction
Associated with hepatitis C
Presentation of pityriasis rosea
Herald patch” followed days later by other scaly erythematous plaques, often in a “Christmas tree” distribution on trunk
Multiple pink plaques with collarette scale
Self-resolving in 6–8 weeks
Define sunburns and what it increases the risk of
Acute cutaneous inflammatory reaction due to excessive UV irradiation
Causes DNA mutations, inducing apoptosis of keratinocytes
UVB is dominant in sunBurn, UVA in tAnning and photoAging
Exposure to UVA and UVB increases the risk of skin cancer
