Skin disorders and ulcers

Question 1

Outline the pathophysiology of pemphigus vulgaris

Answer 1

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

Question 2

Gross morphology of pemphigus vulgaris

Answer 2

Flaccid intraepidermal bullae caused by acantholysis (separation of keratinocytes, “row of tombstones” on H&E stain)
Oral mucosa is involved
Nikolsky sign ⊕

Question 3

immunofluorescence of pemphigus vulgaris

Answer 3

Reticular pattern around epidermal cells

Question 4

Pathophysiology of bullous pemphigoid

Answer 4

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)

Question 5

Gross morphology of bullous pemphigoid

Answer 5

Tense blisters containing eosinophils; oral mucosa spared
Nikolsky sign ⊝

Question 6

Immunofluorescence of bullous pemphigoid

Answer 6

Linear pattern at epidermal-dermal junction

Question 7

Define Epidermolysis bullosa simplex

Answer 7

AD defect in keratin filament assembly = cytoskeleton disruption leading to epithelial fragility

Question 8

Presentation and course of epidermolysis bullosa simplex and what a skin biopsy would show

Answer 8

Presents early in life with friction-induced skin blistering that primarily affects palms and soles
Heals without scarring
Skin biopsy: intraepidermal cleavage

Question 9

Dermatitis herpetiformis definition

Answer 9

Pruritic papules, vesicles, and bullae (often found on elbows, knees, buttocks)
Deposits of IgA at tips of dermal papillae

Question 10

Association and tx of dermatitis herpetiformis

Answer 10

Associated with celiac disease
Treatment: dapsone, gluten-free diet

Question 11

Erythema multiforme associations and presentation

Answer 11

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)

Question 12

Characteristics of SJS

Answer 12

Characterized by fever, bullae formation and necrosis, sloughing of skin at dermal-epidermal junction (⊕ Nikolsky), high mortality rate

Question 13

What is involved in SJS and associated with a reaction to what

Answer 13

Targetoid skin lesions may appear, as seen in erythema multiforme
Usually associated with adverse drug reaction

Question 14

Toxic epidermal necrolysis definition

Answer 14

More severe form of SJS involving > 30% body surface area
10–30% involvement denotes SJS-TEN

Question 15

What is the etiology and location of venous ulcers

Answer 15

Chronic venous insufficiency; most common ulcer type
Gaiter area (ankle to midcalf), typically over malleoli

Question 16

Appearance and pain in venous ulcers

Answer 16

Irregular border, shallow, exudative
Mild to moderate pain

Question 17

Associated signs of venous ulcers

Answer 17

Telangiectasias, varicose veins, edema, stasis dermatitis (erythematous eczematous patches)

Question 18

Etiology & location of arterial ulcers

Answer 18

Peripheral artery disease (eg, atherosclerotic stenosis)
Distal toes, anterior shin, pressure points

Question 19

Appearance & pain of arterial ulcers

Answer 19

Symmetric with well-defined punched-out appearance
Severe pain

Question 20

Associated signs in arterial ulcers

Answer 20

Signs of arterial insufficiency including cold, pale, atrophic skin with hair loss and nail dystrophy, absent pulse

Question 21

Etiology & location of neuropathic ulcers

Answer 21

Peripheral neuropathy (eg, diabetic foot)
Bony prominences (eg, metatarsal heads, heel)

Question 22

Appearance & pain in neuropathic ulcers

Answer 22

Hyperkeratotic edge with undermined borders
no pain

Question 23

Associated signs in neuropathic ulcers

Answer 23

Claw toes, Charcot joints, absent reflexes

Question 24

Acanthosis nigricans definition & association

Answer 24

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)

Question 25

Actinic keratosis definition and risk

Answer 25

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

Question 26

Erythema nodosum definition & causes

Answer 26

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

Question 27

Ichthyosis vulgaris definition & what ages do they manifest

Answer 27

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

Question 28

Define lichen planus

Answer 28

6 P’s: Pruritic, purple, polygonal planar papules and plaques
Mucosal involvement manifests as Wickham striae (reticular white lines) and hypergranulosis

Question 29

Infiltrate and associations of lichen planus

Answer 29

Sawtooth infiltrate of lymphocytes at dermal-epidermal junction
Associated with hepatitis C

Question 30

Presentation of pityriasis rosea

Answer 30

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

Question 31

Define sunburns and what it increases the risk of

Answer 31

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