Lesions

Question 1

What is the difference between a primary and secondary lesion?

Answer 1

Primary skin lesion – develop as a direct result of the disease process
Secondary skin lesion – evolve from primary lesions or develop as a consequence of the patient’s activities

Question 2

What is a secondary pyoderma

Answer 2

bacterial infection which is complicating an underlying skin disease

Question 3

What is a papule?

Answer 3

Primary lesion
A small solid elevation of the skin less than 1cm in diameter

Question 4

What is a nodule?

Answer 4

Primary leison
A solid elevation of the skin greater than 1cm in diamtere that usually extends into the deeper skin layers

Question 5

What is plaque (lesion)

Answer 5

Secondary lesion
A large flatter elevation of the skin, sometimes formed by papules coalescing

Question 6

What is a pustule?

Answer 6

Primary lesion
A small circumscribed elevation of the epidermis containing pus

Question 7

What is a macule?

Answer 7

Primary lesion
A circumscribed flat area of change in colour of the skin less than 1 cm in diameter.

Question 8

What is a patch?

Answer 8

Primary lesion
A circumscribed flat area of change in colour of the skin exceeding 1 cm in diameter.

Question 9

What is scale?

Answer 9

Can be primary or secondary lesion
An accumulation of loose cornified fragments of the epidermis

Question 10

What is crust

Answer 10

Secondary lesion
A dried exudate on the skin surface, either serum, blood or pus or a combination

Question 11

What is an erosion?

Answer 11

Secondary lesion
A break in the continuity of the epidermis that does not penetrate the basement membrane

Question 12

What is an ulcer?

Answer 12

Secondary lesion
A break in the continuity of the epidermis that penetrates the basement membrane

Question 13

What is a cyst?

Answer 13

Secondary lesion
A cacvity with an epithelial lining

Question 14

What is a wheal?

Answer 14

Primary lesion
A circumscribed, raised lesion consisting of dermal oedema

Question 15

What is erythema?

Answer 15

Primary lesion
Abnormal redness of skin or mucous membranes

Question 16

What is an epidermal collarette?

Answer 16

Secondary lesion
A circular lesion with a circular rim of scale and or a peeling edge

Question 17

What is a follicular cast?

Answer 17

Primary lesion
An accumulation of keratinous debris around the hair shaft seen protruding from trhe follicular ostium or present when hairs are plucked and examined

Question 18

What is a comedone?

Answer 18

Primary lesion
A dilated hair follicle devoid of hair and plugged with keratinous debris (a ‘blackhead’)

Question 19

What is a sinus/fistula?

Answer 19

Primary lesion
An abnormal passage between a hollow organ and the skin surface

Question 20

What is an excoriation?

Answer 20

Secondary lesion
Erosion or ulceration caused by scratching, biting or rubbing

Question 21

What is lichentification?

Answer 21

Secondary lesion
An accentuation of the skin marking giving an elephant skin like appearance

Question 22

What is a fissure?

Answer 22

Secondary lesion
Linear split through the epidermis into the underlying dermis

Question 23

What is detected via coat brushing/combing?

Answer 23

superficial parasties especially fleas

Question 24

What is detected using an unstained acetate tape strip?

Answer 24

Surface mites

Question 25

What is detected using a superficial skin scrape?

Answer 25

surface parasites

Question 26

What can be detected with a deeper skin scrape?

Answer 26

parasites burrowing in epidermis

Question 27

What is the best site to detect a sarcoptes mite?

Answer 27

lesions on pinnal margin, elbows, hocks and ventrum

Question 28

What are the best sites to look for demodex mites?

Answer 28

areas of alopecia, comedones and hyperprigmentation

Question 29

What are some common pitfalls of skin scrapes?

Answer 29

Question 30

What is demodicosis?

Answer 30

When mites multiply out of control

Question 31

What is the appearance of a telogen hair bulb?

Answer 31

spear shaped rough no pigment

Question 32

What is the appearance of an anagen hair bulb?

Answer 32

rounded smooth +/- pigmented centre bulb may fold around shaft when plucked

Question 33

What does angular broken ends of hair tips indicate?

Answer 33

self-inflicted hair loss and probable pruritus

Question 34

What is a Wood's Lamp exam and when would you use it?

Answer 34

In any patient suspected of having ringworm Illuminate area of interest in a darkened room - microsporum canis will show green fluorescence Negative fluorescence does not mean dermatophytosis is not present

Question 35

How can you confirm dermatophytosis after performing a Wood's lamp exam?

Answer 35

Perform fungal culture using McKenzie toothbrush technique

Question 36

What is skin surface cytology used for?

Answer 36

visualising cells and microbes on skin surface

Question 37

What type/site of lesion and staining is used for a direct impression smear?

Answer 37

Moist/greasy lesions e.g., ruptures pustule, skin under crusts Accessible sites Diff-quick stain (fixative, eosin and methylene blue)

Question 38

What type/site of lesion and staining is used for a cotton bud smear/indirect impression smear?

Answer 38

Ear canal Diff quick stain (fixative, eosin and methylene blue)

Question 39

What type/site of lesion and staining is used for an acetate tape strip

Answer 39

Dry lesions Less accessible sites e.g., interdigital, skin folds Eosin and methylene blue staining

Question 40

How do you perform a direct impression smear?

Answer 40

Glass slide pressed direct onto surface of lesion, air dried and stained

Question 41

How do you perfrom an indirect impression smear/cotton bud swab?

Answer 41

Insert into ear canal and roll cotton bud on skin surface. Then roll sample onto microscope slide. Heat fix/air dry and stain

Question 42

Why do you not use fixative (A) when staining an acetate tape strip?

Answer 42

may become brittle/cloudy sample is already fixed by adhesion on tape

Question 43

What methods are there to visualise cells/microbes below skin surface?

Answer 43

Fine needle aspiration (FNA) for cytology (placed on slide and examined under microscope) Tissue biopsy for histopathology (sent to external lab)

Question 44

When would you use bacterial culture on a skin surface swab?

Answer 44

If you needed to know the precise identity of a bacteria or its antibiotic suscepitibilty pattern

Question 45

What skin lesion is this?

Answer 45

Papule

Question 46

What skin lesion is this?

Answer 46

Nodule

Question 47

What skin lesion is this?

Answer 47

Plaque

Question 48

What skin lesion is this?

Answer 48

vesicle

Question 49

What skin lesion is this?

Answer 49

Bulla

Question 50

What skin lesion is this?

Answer 50

Patch/macule

Question 51

What skin lesion is this?

Answer 51

Scale

Question 52

What skin lesion is this?

Answer 52

Crust

Question 53

What skin lesion is this?

Answer 53

Hypopigmentation

Question 54

What skin lesion is this?

Answer 54

Hyperpigmentation

Question 55

What skin lesion is this?

Answer 55

Erosion

Question 56

What skin lesion is this?

Answer 56

Ulcer

Question 57

What skin lesion is this?

Answer 57

Wheal

Question 58

What skin lesion is this?

Answer 58

Erythema

Question 59

What skin lesion is this?

Answer 59

Cyst

Question 60

What skin lesion is this?

Answer 60

Epidermal collarette

Question 61

What skin lesion is this?

Answer 61

Follicular cast

Question 62

What skin lesion is this?

Answer 62

Comedone

Question 63

What skin lesion is this?

Answer 63

Sinus/fistula

Question 64

What skin lesion is this?

Answer 64

Excoriation

Question 65

What skin lesion is this?

Answer 65

Lichenification

Question 66

What skin lesion is this?

Answer 66

Fissure