Introduction to dermatology

Question 1

What are the layers of the epidermis? (5)

Answer 1

From superficial to deep:
Stratum corneum
Stratum lucidum 
Stratum granulosum 
Stratum spinosum 
Stratum basale

Question 2

What are Langerhans cells?

Answer 2

Part of the dendritic cell family

They are involved in antigen presentation (process them) and they migrate to lymph nodes to induce an immune response

Question 3

What are the 3 layers of skin called?

Answer 3

Epidermis
Dermis
Subcutaneous tissue (hypodermis)

Question 4

Function of subcutaneous tissue

Answer 4

Fat energy store
Insulation
Fibrous bands anchor skin to fascia

Question 5

What does the dermis contain?

Answer 5

Contains nerve endings
Oil
Sweat glands
Hair follicles 
Also has fibroblasts, dermal dendritic cells and macrophages

Question 6

What are melanocytes

Answer 6

Cells located in the stratum basale that make melanosomes (collections of melanin).

These are excreted and phagocytosed into keratinocytes where they sit above the nucleus

Question 7

What is the active hair growing phase called?

Answer 7

Anagen

80-90% of hair

Question 8

What happens in the Catagen phase in the hair cycle

Answer 8

2-3 week phase where growth stops/follicle shrinks

1-3% of hairs

Question 9

Telogen phase of hair cycle

Answer 9

Resting phase for 1-4 months

up to 10% of hairs in a normal scalp

Question 10

Functions of the skin (6)

Answer 10

Thermoregulation
Skin immune system
Barrier 
Sensation - temp/touch/pain
Vit D synthesis 
Interpersonal communication

Question 11

How does skin act as a barrier?

Answer 11

Protects against Mechanical, Chemical, microorganisms, UV light

Keeps in water and Electrolytes, Macromolecules

Question 12

How does the skin synthesise Vitamin D?

Answer 12

UV light converts 7-dehydrocholesterol to cholecalciferol

Question 13

What is meant by interpersonal communication

Answer 13

Your physical appearance, smell and self identity

Question 14

What % of derm patients are in primary vs secondary care

Answer 14

3% see a dermatologist

17% are looked after in primary care

80% don’t see any doctor about their problem

Question 15

Importance of skin disease? The 5 D’s

Answer 15

Disfigurement
Discomfort
Disability 
Depression
Death

Question 16

External causes of skin disease (5)

Answer 16

Temperature
UV
Chemical (allergen or irritant)
Infection
Trauma

Question 17

Internal causes of skin disease (4)

Answer 17

Systemic
Genetics
Drugs
Infection

Question 18

What is Photo-sensitivity?

Answer 18

An extreme sensitivity to UVA, UVB, visible light or a combination of these

Commonly caused by medications

Exposed sites affected

Question 19

Difference between UVA and UVB?

Answer 19

Ultraviolet A (UVA) has a longer wavelength, and is associated with skin aging.

Ultraviolet B (UVB) has a shorter wavelength and is associated with skin burning.

Question 20

Cold injuries to the skin (4)

Answer 20

Frostbite
Skin necrosis
Cold urticaria
Chillblains - small lesions caused by the inflammation of tiny blood vessels after exposure to cold air

Question 21

What is cold urticaria?

Answer 21

hives (urticaria) or large red welts form on the skin after exposure to a cold stimulus

Question 22

What is Bullous Pemphigoid?

Answer 22

An autoimmune skin disease - may form blisters

Question 23

Define the term ‘Macule’

Answer 23

Small circumscribed (confined) area

Question 24

Define the term ‘Patch’

Answer 24

Larger circumscribed area

Question 25

Define the term 'Papule'

Answer 25

Small raised area

Question 26

Define the term 'Plaque'

Answer 26

Larger raised area

Question 27

Define the term 'Vesicle'

Answer 27

Small fluid filled

Question 28

Define the term 'Bulla'

Answer 28

Large fluid filled

Question 29

Define the term 'Pustule'

Answer 29

Small pus filled

Question 30

Define the term 'Abscess'

Answer 30

Large pus filled

Question 31

Define the term 'Erosion'

Answer 31

Loss of epidermis

Question 32

Define the term 'Ulcer'

Answer 32

Loss of epidermis and dermis

Question 33

What are the most common skin conditions (10)

Answer 33

``` Acne Psoriasis Rosacea Skin lesions Urticaria Warts Leg ulcers Scalp/nail disorders Eczema Infections/infestations ```

Question 34

Eruptive xanthoma can be caused by which condition

Answer 34

Hyperlipidaemia

Question 35

What is Acanthosis Nigricans

Answer 35

A brown to black, poorly defined, velvety hyperpigmentation of the skin. It is usually found in body folds (flexural disrtibution) Associated with insulin resistance, obesity or malignancy

Question 36

Thyroid skin disease

Answer 36

Pretibial myxoedema 5% of Grave's disease Same process occurs behind the eyes - mucinosis

Question 37

What investigations can be done if a bacterial skin infection is suspected (2)

Answer 37

Charcoal swab Microscopy, culture and sensitivity (MC&S)

Question 38

What investigations can be done if a viral skin infection is suspected (3)

Answer 38

Viral swab for PCR Can swab vesicle/bulla if vesicular eruption If systemic illness, can take throat swab

Question 39

What investigations can be done if a fungal skin infection is suspected (4)

Answer 39

Skin scraping Nail clipping Hair sample Fungal cultures