histology of inflammatory dermatoses

Question 1

what are 8 functions of the skin

Answer 1

1. maintaining integrety;
2. protection from injury;
3. absorption/excretion;
4. thermoregulation;
5. metabolic/synthetic;
6. sensory
7. cosmetic;
8. barrier;

Question 2

what are the 2 major layers of the skin

Answer 2

dermis; epidermis

Question 3

what are the 2 different types of skin

Answer 3

thick hairless; thin hairy

Question 4

where is hairless skin found and what is it designed to do

Answer 4

found on the palms and soles, designed to bare weight

Question 5

composition of hairless skin

Answer 5

subcutis - thick
dermis - contains sweat ducts, vessels and nerves
epidermis - opening for sweat duct

thicker to help withstand pressure

Question 6

composition of hairy skin

Answer 6

dermis - contains sweat glands, hair follicles, erector pilli muscle, vessels and nerves
epidermis - opening for sweat gland duct and hair shaft

Question 7

what are inflammatory dermatoses

Answer 7

a wide range of diseases triggered in response to injury

Question 8

examples of inflammatory dermatoses

Answer 8

eczema; psoriasis; acne; lichen planus

Question 9

where does psoriasis typically occur

Answer 9

extensor surfaces (front of knees, elbows etc.)

Question 10

what is auspitz sign

Answer 10

pinpoint bleeding seen after scales are scraped off

Question 11

what is lichen planus

Answer 11

“flat moss” - a systemic disease that involves the skin and mucose and presents as purple, itchy, flat bumps + Wickham’s striae that develop over several weeks

Question 12

what are wickham’s striae

Answer 12

fine, white lines forming a lace-like pattern on the surface of lichen planus flat-topped papules; easier to spot if you apply a thin layer of oil to the surface of the top of the lichen planus lesions

Question 13

what is bullous pemphigoid

Answer 13

adhesion problem between baseal keratinocytes and basal membrane -> result in an itchy, raised rash

Question 14

what is the epithelium like in lichen planus

Answer 14

hypertrophic, eaten away by dermal-epidermal inflammatory response ->results in keratyocytes

Question 15

vasculitis histology

Answer 15

fibrin and luekocytes leak out from vessels into tissues

Question 16

acne MOA

Answer 16

sebum changes with testosterone release (becomes thicker and increases in production) -> exretion from hair follicle doesn’t happen normally -> hair follicle dilates -> can rupture and results in breeding ground for bacteria -> secondary infection, pus and inflammation occurs -> resolves when hormone levels normalise

Question 17

what is granuloma annulare

Answer 17

flat round plaqures arising from a granluomatas inflmmation in the dermis in reaction to interstitial collagen; pathogeneis poorly understood

Question 18

granuloma annulare histology

Answer 18

central disorganised collagen surrounded by histocytes

Question 19

what affects the efficacy of topical drugs

Answer 19

inherent potency; ability to penetrate skin - integrity of stratum, frequency of application, conc of medication, compliance

Question 20

4 things that affect the pharmacokinetics of drugs

Answer 20

anatomy/site; hydration; type of compound; age

Question 21

4 diseases that are highly responsive to steriods

Answer 21

psoriasis; atopic dermatitis (eczema); seborrheic dermatitis; intertrigo

Question 22

retinoids role

Answer 22

regulate the cell apoptosis, differentiation and proliferation

Question 23

retinoids MOA

Answer 23

act on keratinocytes (attached to TF) -> initiate proliferation on basal epithelium -> epidermal hyperplasia

Question 24

what are topical calcineurin inhibitors

Answer 24

a form of NSAID -> target pro-inflammatory cytokines (useful in atopic dermatitis itch)

Question 25

topical calcineurin inhibitor MOA

Answer 25

stop the action of calcineurin+calmodulin binding -> TFs are not dephosphorylated -> TFs can’t activate gene expression in the nucleus

Question 26

3 ways to enhance uptake of drugs by the skin

Answer 26

1. iontophoresis;
2. electroporation;
3. sonophoresis (using ultrasound)

Question 27

what is imiquimod

Answer 27

a topical immunotherapy

Question 28

what does the factor indicate on sunscreen

Answer 28

the amount of time (min) the sunscreen will protect your skin from UV rays