Introduction to Dermatology

Question 1

What skin condition can happen in diabetes?

Answer 1

Dermatolipsclerosis

Question 2

What is pitiriasis?

Answer 2

Scaling

Question 3

What pathological processes can occur in the skin?

Answer 3

Infective
Immunological
Neoplastic
- Benign; eg: psoriasis
- Malignant
Inflammatory
Traumatic
Metabolic
Genetic

Question 4

Which part of the skin structure is psoriasis a disease of?

Answer 4

Basement membrane

Abnormal epidermal cells > produce keratin > scale

Question 5

Which part of the skin does urticaria occur in?

Answer 5

Dermis

Question 6

What are the functions of the skin?

Answer 6

Protection from environment
- Physical
- Immune
Thermoregulation
Vitamin D synthesis
Keeps organs inside
Sensation
Aesthetic

Question 7

What are the three layers of the skin, from superficial to deep?

Answer 7

Epidermis
Dermis
Subcutis/panniculus/hypodermis

Question 8

What primarily makes up the epidermis?

Answer 8

Keratinocytes

Question 9

What primarily makes up the dermis?

Answer 9

Fibroblasts
Collagen
Elastic fibres

Question 10

What makes up the hypodermis?

Answer 10

Fat

Question 11

What are the four main layers of the epidermis, from superficial to deep?

Answer 11

Stratum corneum
Stratum granulosum = granular cell layer
Stratum spinosum = spiny layer
Stratum basale = basal cell layer

Question 12

In which direction do epidermal cells mature?

Answer 12

Deep to superficial

Question 13

Describe the stratum basale

Answer 13

Source of epidermal stem cells
Site of cell division
Keratinocytes start here and move upwards

Question 14

Describe the stratum spinosum

Answer 14

Centre of epidermis

Has spiny appearance due to desmosomal junctions

Question 15

Describe the stratum granulosum

Answer 15

Lipids produced by keratinocytes secreted into extracellular space
Forms water barrier > keeps water in skin

Question 16

Describe the stratum corneum

Answer 16

Made of desquamating keratinocytes
Thick outer layers of flattened keratinised non-nucleated cells
Barrier against trauma and infection

Question 17

What is the most common form of skin cancer?

Answer 17

Basal cell carcinoma

Question 18

What are the cells of origin of basal cell carcinoma?

Answer 18

Basal keratinocytes

Question 19

What are the three main cell types in the epidermin?

Answer 19

Keratinocytes
Melanocytes
Langerhans cells

Question 20

What is the ratio of keratinocytes to melanocytes?

Answer 20

10:1

Question 21

What do melanocytes do?

Answer 21

Produce pigment = melanin

Transfer melanin to keratinocytes via dendrites in stratum basale

Question 22

What are melanocytic nevi?

Answer 22

Moles = benign collections of melanocytes

Question 23

What is a melanoma?

Answer 23

Malignancy of melanocytes

Question 24

What is the main function of Langerhans cells?

Answer 24

Immune = dendritic cells

Question 25

What are the two layers of the dermis?

Answer 25

Papillary dermis | Reticular dermis

Question 26

What is the function of the dermis?

Answer 26

Support

Question 27

What does the dermis contain?

Answer 27

``` Blood Lymphatics Nerves Sweat glands Hair follicles ```

Question 28

What are the cells of the dermis?

Answer 28

Fibroblasts | Mast cells

Question 29

What are kelloids?

Answer 29

Abnormal scars | Uncontrolled synthesis and excessive deposition of collagen at sites of prior dermal injury and wound repair

Question 30

What is the major effector cell in urticaria?

Answer 30

Mast cell

Question 31

What is the function of the hypodermis?

Answer 31

Insulates body Energy supply Cushions and protects skin Allows for skin mobility over underlying structures

Question 32

What is erythema nodosum?

Answer 32

Inflammation of hypodermis

Question 33

What makes up the pilosebaceous unit?

Answer 33

``` Hair follicle Sebaceous glands Apocrine glands - Only in axillary and anogenital areas - Open directly into hair follicle Arrector pili muscle ```

Question 34

Where do eccrine glands open to?

Answer 34

Directly onto skin surface | Present throughout body

Question 35

What questions do you ask in a history of a rash?

Answer 35

``` When did it begin? - Context of onset Where on the body did it begin? How has it evolved so far? - Sites - Has the rash itself changed? Symptoms of rash Have you had something similar before Other sites involved - Mucosal surfaces - Hair - Nails - Teeth Exacerbating factors Have you tried any treatments? Have you come into contact with any new substances? Have you started any new medications? Associated features Have others around you had a similar rash? ```

Question 36

What are the red flag symptoms associated with a rash?

Answer 36

``` Shortness of breath Tongue swelling Joint pain Fever and sweats New lumps or bumps ```

Question 37

What questions do you ask in a history of a lesion?

Answer 37

``` When did it develop? Is it new or old? Does it come and go, or stay? How many lesions are there? How has it changed over time? - Size - Shape - Colour Have you had a similar lesion before? Symptoms of lesion Sun exposure history Past history of skin cancers Treatment for skin cancers in past Family history of skin cancers ```

Question 38

What is erythema?

Answer 38

Redness of skin due to vasodilation

Question 39

What is erythroderma?

Answer 39

Erythema over >90% of body surface area

Question 40

What is scale?

Answer 40

Abnormal accumulation of keratin | Surface change

Question 41

What is a macule?

Answer 41

Flat area of altered skin colour | Impalpable

Question 42

What is a papule?

Answer 42

Elevated lesion | Less than 5 mm

Question 43

What is a nodule?

Answer 43

Elevated lesion | More than 5 mm

Question 44

What is a cyst?

Answer 44

Nodule with fluid within

Question 45

What is a plaque?

Answer 45

Circumscribed, elevated area of skin | Breadth greater than thickness

Question 46

What is a wheal?

Answer 46

Area of localised oedema of skin

Question 47

What is a vesicle?

Answer 47

Fluid-filled blister

Question 48

What is a pustule?

Answer 48

Vesicle/bulla containing pus | - Pus can be sterile

Question 49

What is an erosion?

Answer 49

Superficial loss of epidermis | Doesn't scar

Question 50

What is an ulcer?

Answer 50

Area of tissue loss through dermis | Forms scar

Question 51

What is a crust?

Answer 51

Scab = dried exudate | Forms erosion/ulcer

Question 52

What is telangiectasia?

Answer 52

Dilated blood vessels

Question 53

What are petechiae?

Answer 53

Pinpoint bleeding into skin/mucosae | Doesn't blanch

Question 54

What are purpura?

Answer 54

Discolouration of skin/mucous membranes Due to bleeding from small vessels Non-blanching

Question 55

What is sclerosis?

Answer 55

Hardening of subcutaneous tissue and dermis

Question 56

What is atrophy?

Answer 56

Thinning of epidermis

Question 57

How do you describe the distribution of a skin pathology?

Answer 57

Flexural/extensor Sun-exposed Follicular/non-follicular Symmetrical

Question 58

What are red flags in skin pathology?

Answer 58

``` Skin pain Blisters/pustules, especially if widespread Punched out lesions Mucosal involvement Rapid change in any presentation Purpura Confluent erythema Facial swelling Tongue swelling Hoarse voice Difficulty swallowing/breathing Urticaria Change in - Size - Shape - Colour ```

Question 59

What are other concerning features associated with skin lesions?

Answer 59

``` Shortness of rbeath Joint pain and swelling Fever Sweats Lymphadenopathy Pregnancy Contacts ```