Intro to dermatology

Question 1

what are some other structres associated with the skin?

Answer 1

glands, hair, nails, sensory structures

Question 2

what are the 3 layers of skin?

Answer 2

• epidermis
• dermis
• subcutaneous tissue

Question 3

what is the function of subcutaneous tissue & what does it contain?

Answer 3

• fat energy store
• insulation
• contains blood vessels & nerves

Question 4

what is the function of the dermis?

Answer 4

• a matrix of collagen & elastin fibres, surrounded by an extracellular gel-like substance
• these fibres give skin its stregnth & elasticity

Question 5

what is the epidermis made up of?

Answer 5

• straified squamous epithelium
• 3 cell types, but keratinocytes are main cell type, others are melanocytes & langerhans cells
• 5 layers

Question 6

where are keratinocytes formed and where do they migrate to?

Answer 6

originate in stratum basale and differentiate as they migrate out towards the surface, where they are shed

Question 7

what are the 5 layers of the epidermis?

Answer 7

• stratum basale
• stratum spinosum
• stratum granulosum
• stratum lucidum
• stratum corneum

Question 8

what is the function of melanocytes?

Answer 8

synthesise melanin, which is then transferred to keratinocytes to give protection against UV rays

Question 9

what is the function of Langerhans cells?

Answer 9

process antigens & migrate to Lymph nodes to induce an immune response

Question 10

does skin have ability to regenerate? if so, how come?

Answer 10

yes, because of stem cells found throughout hair follicles

Question 11

detail nail anatomy

Answer 11

Question 12

losing what part of nail anatomy is more likely to lead to infection?

Answer 12

cuticle

Question 13

Describe the hair cycle

Answer 13

• Anagen
• 80-80% of hair
• Catagen
• 2-3week phase growth stops/follicle shrinks
• 1-3% of hair
• Telogen
• resting phase for 1-4months

Question 14

What are the most important functions of skin? (6)

Answer 14

• Thermoregulation

–Insulation, Heat transfer (sweat)

•Skin immune system

–Innate (ie skin, macrophages & complement)

•Barrier

–Protects against Mechanical, Chemical, microorganisms, Ultraviolet light

–Keeps in water and Electrolytes, Macromolecules

•Sensation

–Temperature, touch and pain

• Vitamin D synthesis
• Interpersonal Communication

–Physical appearance, smell, self -identity

Question 15

What are the main 2 categories of skin disease and give examples of them

Answer 15

• External - temperature, UV, chemical, infection
• Internal - systemic disease, genetics, drugs, infection

Question 16

What category is this an example of, and what is it called?

Answer 16

• external cause- temperature (cold)
• COLD URTICARIA

Question 17

When describing skin lesions, small refers to what size?

Answer 17

<5mm

Question 18

When describing skin lesions, what is a macule?

Answer 18

small circumscribed area

Question 19

When describing skin lesions, what is a patch?

Answer 19

a larger circumscribed area

Question 20

When describing skin lesions, what is a papule?

Answer 20

small raised area

Question 21

When describing skin lesions, what is a plaque?

Answer 21

larger raised area

Question 22

When describing skin lesions, what is a vesicle?

Answer 22

small fluid filled

Question 23

When describing skin lesions, what is a bulla?

Answer 23

large fluid filled

Question 24

When describing skin lesions, what is a pustule?

Answer 24

pustule = small pus filled

Question 25

When describing skin lesions, what is an abscess?

Answer 25

large pus filled

Question 26

When describing skin lesions, what is an erosion?

Answer 26

loss of epidermis

Question 27

When describing skin lesions, what is an ulcer?

Answer 27

loss of epidermis and dermis

Question 28

why do ulcers heal with scarring?

Answer 28

because they have dermal loss as well

Question 29

What is this & what can it represent ?

Answer 29

eruptive xanthoma - hyperlipidemia

Question 30

what are nails made of & where do they arise?

Answer 30

made of hardened keratin & arise from nail matrix, just under nail fold

Question 31

What is this & what is it seen in?

Answer 31

• Myxedema
• seen in thyroid skin disease

Question 32

in suspected bacterial infection, what investigations do you do?

Answer 32

• Charcoal swab- plain cotton bud, rub on area of affected skin, looking for areas with exudate, bright ulcers etc
• MC & S (microscopy, culture & sensitivty)

Question 33

In suspected viral infection, what investigations do you do?

Answer 33

• viral swab for PCR
• can swab vesicle / bulla if vesicular eruption, or pop with needle to get a swab of exudate
• in systemic illness, take throat swab

Question 34

If fungal infection suspected, what investigation do you do?

Answer 34

• skin scraping
• nail clipping
• hair sample
• fungal cultures