13.4 Ulcers & Crusts

Question 1

Define erosion

Answer 1

• Wound/lesion due to loss of stratum corneum
• Epidermis affected, dermis intact
• Superficial lesion
• Heals without scarring
• painful because nerve ending are still intact

Question 2

Define ulcer

Answer 2

• Wound/lesion due to loss of epidermis
• Epidermis & dermis affected
• Deeper lesion (sometimes extending into subcutis)
• Heals with scarring

Question 3

Define crusts

Answer 3

• Dried exudate on the skin surface
• Either serum, blood, pus or a combination
• Commonly seen in diseases with a pustular component
• E.g. exudate from an erosion or ulcer that has dried
• (No scarring)

Question 4

Pathogenesis General

Answer 4

1. Tissue injury (outside / inside)
2. Inflammatory response (at site of injury)
3. Impaired healing
4. Tissue necrosis
5. Ulcer formation

Question 5

Pathogenesis detail

Answer 5

1.Tissue injury:
- initial step in the pathogenesis of skin ulcers is tissue injury
- caused by various factors such as trauma, pressure, infection, or a combination of these factors.

2.Inflammatory response:
- After tissue injury, an inflammatory response is triggered. This response involves the release of inflammatory mediators such as cytokines and chemokines, which recruit immune cells to the site of injury to begin the healing process.

3.Impaired healing:
- In some cases, the inflammatory response may be impaired, leading to delayed or inadequate healing. This can be due to underlying medical conditions such as diabetes or vascular disease, which impair blood flow and oxygen delivery to the affected area, hindering the healing process.

4.Tissue necrosis:
- If the inflammatory response is inadequate, tissue necrosis may occur, resulting in the death of skin cells and tissues.

5.Ulcer formation:
- The combination of tissue injury, impaired healing, and tissue necrosis can lead to the formation of a skin ulcer. The type of ulcer formed depends on the underlying cause of the injury, as well as the location and severity of the damage.

Question 6

Causes of ulcers

Answer 6

• Traumatic causes - burns, pressure sores
• Vascular causes - insufficiency, infarcts, emboli
• Inflammatory causes - autoimmune (lupus), bullous diseases
• Infective causes - bacterial, fungal, viral
• Malignant causes - carcinoma, lymphoma etc.

Question 7

Vascular causes

Answer 7

• Venous stasis – Most common cause of leg ulcers
• Arterial (infarction/embolus)

Question 8

Infective causes

Answer 8

• Bacterial - Staph, Strep
• Viral - HSV (Herpes simplex virus), VZV (Varicella zoster virus)
• Tuberculosis (TB)
• Leprosy
• Deep fungal infections

Question 9

Malignant causes

Answer 9

• SCC (Squamous cell carcinoma) – most common malignant cause
• BCC (Basal cell carcinoma)
• Malignant melanoma
• Lymphoma (T-cell, B-cell)
• Metastases

Question 10

Causes of leg ulcers

Answer 10

From most common, to least common
- venous
- infectious (viral, bac, fungal, protozoal)
- neoplasms (SCC>BCC)