Dermatology

Question 1

what are the cell types found in the epidermis?

Answer 1

keratinocytes
langerhan cells: antigen presenting cells.
melanocytes: protect nuclei from UV via melanin.
merkel cells: specialised nerve endings for sensation.

Question 2

what are the 4 layers of the epidermis?

Answer 2

stratum basale
stratum spinosum
stratum franulosum
(stratum lucidum: in palms and soles.)
stratum corneum (horny layer most superficial)

Question 3

what changes occur in epidermis on pathology?

Answer 3

change in turnover.
change in surface of skin.
change in pigmentation.

Question 4

what makes up the dermis?

Answer 4

collagen, elastin, glycosaminoglycans for strength and elasticity.
also immune cells, nerve cells, skin, lymphatics, blood vessels.

Question 5

what is the function of the sebaceous gland?

Answer 5

sebum through hair follicles to lubricate skin, stimulated after puberty by androgen to dihydrotestosterone.

*increased sebum and bacteria acne vulgris.

Question 6

what are the functions of eccrine and apocrine glands?

Answer 6

regulate body temp innervated by sympathetic system.

*eccrine are widespread and apocrine active after puberty in axillae, genitalia etc.

Question 7

what are the 3 types of hair found on skin?

Answer 7

lanugo: fine soft hair on foetus.
vellum: short all over body.
terminal: coarse long hair.

*consists modified keratin is divided into hair shaft and bulb.

3 growth stages: anagen, catagen, telogen.

Question 8

what makes nails?

Answer 8

• nail plate with matrix at posterior and rest on nail bed.

- contains blood capillaries.

Question 9

what are the important aspects to consider in a dermatology related history?

Answer 9

• periodicity: timing, previous, triggers.
• location.
• associated symptoms.
• medication: any tried and results.
• social history: occupation, pets, travel, family.
• impact on patient: psychological.

Question 10

how would you describe skin changes?

Answer 10

morphology: structure on skin change. flat/raised.
distribution: pattern, consider hair and nails.
colour: symmetry, around it too, consider dif. skin tones.
size: compare to objects, measure, photos.
shape.
border: edges of change.

Question 11

what causes acne vulgaris?

Answer 11

increased sebum production blocking pilosebaceous follicles. can be hormonal.
leads to inflammatory changes in skin and comedomes.
*topical/ antibiotics and non.

Question 12

how does Eczema present?

Answer 12

inflammation with relapsing, remitting pattern, common in skin creases as response to specific trigger.
- pattern and itch characteristic. dry skin, associated with hayfever and asthma.

*education, emollients, topical anti-inflammatories.

Question 13

how does shingles present?

Answer 13

reactivation of dormant varicella zoster causing localised dermatomal pattern of rash.

• v infectious so advice!
• acyclovir important to prevent post-herpetic neuralgia.

Question 14

what is psoriasis?

Answer 14

inflammatory with relapsing, remitting pattern caused by multi-factorial auto-immune causes leading T cells cytokine production stimulates and leads to keratinocyte proliferation.

• plaque psoriasis common.
• identify triggers or iatrogenic causes (medical history important) eg:ACEi, NSAIDs etc.

Question 15

how does plaque psoriasis present?

Answer 15

• itchy, well demarcated circular, oval pink plaques with symmetrical distribution with overlying white or silvery scale.
• topical first line, phototherapy second and bio therapies third.

Question 16

what is malignant melonoma?

Answer 16

• cancerous change in melanocyte growth with potential to spread if reaches dermis.
• UV exposure main risk with skin type and genetics.
• biopsy and treat with excision, chemo, radiotherapy, palliative.

Question 17

how do you assess pigmented lesion?

Answer 17

Asymmetry
Border irregular*
Colour irregular*
Diameter greater than 7mm
Evolving

• size change, irregular shape and colour major features (2points)
• minors like 7mm, inflammation, oozing 1 point.

Question 18

what is squamous cell carcinoma?

Answer 18

• from keratinising cells of epidermis, invasive and can spread.
• UV exposure main risk with skin type and genetics.
• lack of healing and resolution.
• nodule to ulceration with raised edges.
• biopsy and treat w/moh’s micrographic surgery, low mortality.

Question 19

what is basal cell carcinoma?

Answer 19

• malignant epidermal skin tumour from hair follicles, slow growing with only local invasion.
• UV risk and v rare in dark skin.
• biopsy and moh’s micrographic surgery.

Question 20

how would you use pneumonic SCAM to describe lesions?

Answer 20

Site, distribution, Size and Shape.
Colour and configuration.
Associated changes (surface features)
Morphology

Question 21

what terms could you use when describing site and distribution?

Answer 21

generalised or flexural?

at extensor or photosensitive areas?

Question 22

how would you describe its configuration?

Answer 22

discrete: distinct lesions, separate from each other with identifiable borders.
confluent: lesions merge together.
linear.
target: bull’s eye lesion with central clearing.

Question 23

how would you describe colour changes in rashes?

Answer 23

erythematous: red and blanching.
purpuric: red or purple and non-blanching.
brown/ black: pigmented or hyperpigmented.
hypopigmented: loss of colour.

Question 24

what kind of surface features would you notice?

Answer 24

scale: keratin buildup.
crust: dried up exudate.
excoriation: erosion from scratching/ pruritus.
erosion/ulceration: partial or full thickness loss.