Derm - Degeneration/Necrosis (Final)

Question 1

What is a vesicle?

What are possible causes?

Answer 1

• palpable elevation filled with a clear fluid
• if over 1 cm, called a bulla
• causes: auto-immune dermatoses, viral infections, chemical irritants, burns

Question 2

What 3 changes can lead to the formation of a vesicle?

Answer 2

• intercellular edema
• intracellular edema
• disruption of intercellular junctions

Question 3

What is a pustule?

What is a possible cause?

Answer 3

• palpable elevation filled with pus

- caused by leukocyte infiltrate

Question 4

What is crust?

What are possible causes of crust?

Answer 4

• dried exudate, serum, blood, and scale that is adhered to the skin surface
• causes: severe disorders of keratinization, severe pustular dematitis, secondary to ulcers

Question 5

What is a papule?

What are causes of papules?

Answer 5

• palpable, solid, elevated mass less than 1 cm

- causes: infiltrate of inflammatory cells, infiltrate of neoplastic cells, epidermal hyperplasia, deposit of mineral

Question 6

What is a nodule?

Answer 6

a papule that is greater than 1 cm, and deeper

Question 7

What is a plaque?

Answer 7

coalesced papules

Question 8

What is an ulcer?

What are causes?

Answer 8

• loss of epidermis with exposure of dermis

- causes: secondary to: epidermal necrosis, inflammation, infarction, neoplasia

Question 9

What is scale?

What are the causes?

Answer 9

• accumulation of loose keratinized cells

- causes: disorders of keratinization, chronic dermatitis

Question 10

What is an epidermal collarette?

Answer 10

a circular rim of scale that occurs secondary to rupture of a vesicle, pustule, or papule

Question 11

What is lichenification?

What is the cause?

Answer 11

• thickening and hardening of the skin

- caused by chronic irritation/inflammation

Question 12

Describe the types of Primary Photosensitization

Answer 12

Type 1: exogenous
- drugs or plants containing photosensitive chemicals
- St Johns wort, griseofulvin
Type 2: intrinsic
- porphyria
- inherited deficiency of proporphyrinogen cosynthetase, leading to defect in heme synthesis and build up of porphyrins

Question 13

Describe secondary photosensitization

Answer 13

• Type 3: hepatogenous
• poor hepatic clearance of phylloerythrin
• toxins cause biliary obstruction

Question 14

Describe the gross appearance of acute solar injury, and the pathogenesis

Answer 14

• gross: erythema, blistering/vesicles, sloughing of necrotic skin
• path: direct cellular injury by ionizing radiation

Question 15

Describe the gross appearance of chronic solar injury

Answer 15

• epidermal hyperplasia, dermal fibrosis, and elastosis

- solar/actinic keratosis

Question 16

1st degree burns

• tissue affected
• gross appearance
• healing

Answer 16

• epidermis
• reddened/darkened necrotic epidermis
• complete healing

Question 17

2nd degree burns

• tissue affected
• gross appearance
• healing

Answer 17

• epidermis and dermis
• vesicle formation
• epidermal regeneration with some scarring

Question 18

3rd degree burns

• tissue affected
• gross appearance
• healing

Answer 18

• full thickness of epidermis and dermis +/- subcutis
• sloughing of necrotic tissue, followed by granulation tissue
• scar, life threatening

Question 19

Pathogenesis and gross appearance of Erythema Multiforme and Toxic Epidermal Necrolysis

Answer 19

• path: involves type 4 hypersensitivity towards antigens of the surface keratinocytes inducing apoptosis
• widespread coalescing erythematous macules to vesicles and ulcers

Question 20

Differences between Erythema multiforme and Toxic Epidermal Necrolysis

Answer 20

EM: milder
- single cell apoptosis
TEN: more severe
- sheets of apoptotic/necrotic cells resembling a burn