Ulcers & Crusts

Question 1

Erosion definition

Answer 1

• wound/lesion due to loss of stratum corneum
• epidermis affected, dermis intact
• superficial lesion
• heals without scarring

Question 2

Ulcer definition

Answer 2

• wound/ lesion due to loss of epidermis
• epidermis & dermis affected
• deeper lesion (sometimes extending into subcutis/subcutaneous fat)
• heals with scarring

Question 3

Crust definition

Answer 3

• dried exudate on skin surface
• either serum, blood, pus or combo
• seen in diseases with pustular component
• eg: exudate from erosion / ulcer that has dried (on surface of skin)
• no scarring

Question 4

Secondary morphologies

Answer 4

Ulcers = heal with scarring, atrophy/ hypertrophic scar (fibrosis), leave pigmentation (hypo/hyper)
Erosion = superficial, painful because nerve ending kept intact
Scale = dried/ flaky skin on skin surface
Crust = dried exudate on skin surface eg: no scarring
Excoriation
Lichenification

Question 5

1. Tissue injury (Pathogenesis of ulcer)

Answer 5

• external/internal
• various factors eg: trauma, pressure, infection/ combo of these factors

Question 6

2. Inflammatory response (Pathogenesis of ulcer)

Answer 6

• release of inflammatory mediators eg: cytokines & chemokines
  = recruit immune cells to site of injury to begin healing process

Question 7

3. Impaired healing (Pathogenesis of ulcer)

Answer 7

• inflammatory response may be impaired = delayed/ inadequate healing
• underlying medical conditions eg: diabetes/ vascular disease
  = impair blood flow & oxygen delivery to affected area, hindering healing process

Question 8

4. Tissue necrosis (Pathogenesis of ulcer)

Answer 8

• inflammatory response inadequate, tissue necrosis
  = death of skin cells & tissues

Question 9

5. Ulcer formation (Pathogenesis of ulcer)

Answer 9

• Tissue injury + impaired healing + tissue necrosis = skin ulcer
• Type of ulcer depends on underlying cause of injury, location & severity of damage

Question 10

Causes of ulcers & crusts

Answer 10

• traumatic causes = burns, pressure sores
• vascular causes = venous/arterial insufficiency, infarcts, emboli
• inflammatory causes = autoimmune (lupus), Bullous disease
• infective causes = bacterial, fungal, viral
• malignant causes = carcinoma, lymphoma etc

Question 11

Vascular causes of ulcers & crusts

Answer 11

• venous stasis = most common cause of leg ulcers (older pt, HPT, oedema of lower legs, chronic stasis, damaged valves pooling of fluid & fluid into interstitial tissue triggers healing response = chronic ulcers)
• arterial (infarction/ embolus)

Question 12

Infective causes of ulcers & crusts

Answer 12

• bacterial = staph, strep
• viral = HSV, VZV (common cause - mucosal/skin surface ulcers)
• TB = primary (cutaneous inoculation)/ systemic (dissemination in blood)/ immune response
• leprosy
• deep fungal infections

Question 13

Malignant causes of ulcers & crusts

Answer 13

• SCC = most common malignant cause (typical lesion- erythematous base with ulceration & crust on surface, sun exposed areas)
• BCC
• malignant melanoma
• lymphoma (T-cell, B-cell) = primary/ metastasis
• metastases