Dermatology

Question 1

what are the tumour types of keratinocytes ( what can go wrong?)

Answer 1

you can get BCC, Actinic Keratosis, SCC, sebehorric keratosis

Question 2

what are the characteristics of BCC?

Answer 2

shiny, raised, smooth, telangectasic, in a bed of mucin. Called basaloid nests. due to intense sun in childhood. characterised by pallisading cells. good with punch biopsy

Question 3

what are the characteristics of actinic keratosis?

Answer 3

its the precursor to SCC, brown/ red, flat, scaly, shoing hyper/parakeratosis

Question 4

what are the characteristics of squamous cell carcinoma

Answer 4

brown, due to longterm sun, rough scale, nodular/deep, required excisional biopsy

Question 5

what are the characteristics of sebhorric keratosis?

Answer 5

unsighlty, stuck on, cysts/comedones, benign, on old people mostly

Question 6

what are the characteritistics of wart?

Answer 6

raised, deep/nodular, due to infection ( HPV 6,11), blood dots seen in the center

Question 7

what can go wrong with melanocytes?

Answer 7

you can get a nevus ( atypical or typical) and that may or may not become melanoma.

Question 8

what are the characteristics of a nevus?

Answer 8

it is a melanoma precursor ( potentially), brown. Typical are brown, smooth, symettrical, same color whereas atypicals hae varying edge/ color, are flat, expand out

Question 9

what are the characteristics of melanoma?

Answer 9

think of the ABCDEs: asym, border, colors, diametes ( over 6 mm is bad), expanding. prognosis is based on depth so don’t do a shave biopsy. due to lifelong sun exposure.

Question 10

what is dermatofibroma characterized by?

Answer 10

collagen, a firm, round, brown lesion. It is brown due to the hemosiderin ( iron deposition) and hemorrhage

Question 11

what are the characteristics of hemangioma?

Answer 11

bloody bump. usually presents in the first weeks of life ( so on babies) and resolves by one year, with complete involution by age 5.

Question 12

what are the broad categories of infectious lesions you can get? due to what?

Answer 12

bacterial - impetigo,
viral - HSV/Varicella, molluscum contagiosum
fungal - tinea versicolor, tinea corporis, intertrigo,

Question 13

what does impetigo look like/ characterisitics?

Answer 13

due to s. aureus, can be bullous ( bulla) or nonbullous ( appears with scale)

Question 14

WHAT DOES HSV/VZV appear with?

Answer 14

group vesicles on an erythematous base, diagnose with Tzanck smear. Varicella zoster looks like “ dew drop on a petal” the idea is that they arent grouped, and are crusty papules in a christmas tree distribution

Question 15

Molluscum contagiousom

Answer 15

umbilicated lesion seen in kids due to pox virus. boil and red halo.

Question 16

tinea corporis

Answer 16

is a dermatophyte showing a red ring with a central clearing. use KOH to dissolve the keratin so you can see the fungal hyphae

Question 17

pityriasis versicolor . same as tinea versicolor

Answer 17

spaghetti and meatballs, gives hypopigmentation and macules, seen in sweaty adolescent boy’s backs, turning the backs white. there is no parakeratosis!!! somehow this is important.

Question 18

what the balls is intertrigo?

Answer 18

fungus in the skin folds, i.e. candidate ( so can cause inverse psoriasis). can also be caused by corynebacteria leading to erythrasma. use woodslamp and KOH

Question 19

what are the two blistering conditions?

Answer 19

pemphigus vulgaris, and bullous pemphigoid.

Question 20

which of the two blistering conditions is an emergency?

Answer 20

bullous pemphigus because there is a split above the basal layer, so you lose body fluids and can die from fluid loss through broken blisters. this is scalded skin syndrome. dont microwave your baby dammit!
due to antibodies against desmosomes.

Question 21

what is the cause of bullous pemphigoid and pemphigus vulgaris

Answer 21

antibodies against different things:
in pemphigoid its against the hemodesosomes
in pemphigus its agsinst the desmosomes

Question 22

what are the characteristics of psoriasis?

Answer 22

rete ridges, auspitz sign, silvery scale, patches/plaques, symetrical and circumscribed, nail signs = onycholysis, oil drop, pittin. T9x) is with narrow band UVB light, retinoid acid with Vit A, salysilic acid. Vit D.

Question 23

what are the signs of atopic dermatitis ( eczema)

Answer 23

1) its not a food allergy or connected in any way to food
2) hypertrophic epidermis, spongiosis, lichenification, barrier problem ( filagrin), seen on flexors in infants and extensor surfaces in the adult.

Question 24

what is the eczema triad thing?

Answer 24

atypie: its rhinitis, asthma, and eczema

Question 25

what are the characteristics of lichen planus?

Answer 25

the 5 P’s : polygonal, pruritic, papules, purple, planar in your pussy ( can sometimes cause vaginal stenosis if left untreated). shows wickham striae ( white lines ). your differential is : DRUGS- get them off their meds.

Question 26

what is pityriasis rosea due to/ characteristized by?

Answer 26

there is a herald patch, then appears in a tshirt ( or christmas tree) pattern in 10-20 yr old. It is a papulosquamous rash with collarette. Done miss, might be due to secondary syphilis

Question 27

what is rosacea due to? what are the types?

Answer 27

adult red face ( flushing), has diff types with diff caused

1) erythrotolangectasia - due to chronic alcoholism
2) papulopustular
3) phymatous ( nose) - sebaceous
4) ocular - this is really bad because you can have iritis/ conjunctivitis

Question 28

define androgenic alopexcia

Answer 28

noticable hair loss, at 50% loss of hair ( out of 100,000 strands). Dont lose hair on the back of your head because its a different germ layer. Treatment is fenestride ( an anti androgen)

Question 29

what is notable about alopecia arreata?

Answer 29

exclamation mark hairs come out of your head. the hair comes out in patches. 50% will recover by themselves in 6 months time.

Question 30

what is notable about scarring alopecia - what disease causes this?

Answer 30

scarring alopecia can be from discoid lupus, and when you look for the hair follicle you can’t find it because its plugged = permanent hair loss

Question 31

what are the three signs necessary for you to say someone has psoriatic nails?

Answer 31

1) see oil drop sign - the nail looks yellow, called hyperpigmentation)
2) onycholysis ( detachment of nail from nailbed)
3) pitting

Question 32

tinea unguium- what the balls is this?

Answer 32

when you have fungal-nail : aka onychomycosis.
- very common in big toe, nail gets thick and brittle, lifts off a bit ( called sub-ungal hyperkeratosis), and then you lose the nail ( it falls off)

Question 33

what is trichotilomania? when does it become lifethreatening?

Answer 33

when you have excessive hair plucking? when there is concurrent trichophagomania ( they eat the hairs)

Question 34

what are the acneiform disorders you need to know about?

Answer 34

1) just acne vulgaris, mild, moderate and severe

Question 35

what is mild acne vulgaris characterized by? what is the treatment regimen?

Answer 35

nonscarring comedones. treatment is cleaning and topical retinoic acid/ salicilic acid. You may also try a topical antibiotic

Question 36

what is moderate acne characterized by and what is the treatment?

Answer 36

pustules ( no cysts) + comedomes. treat with same as before, but can add a systemic Abx or OCP. if refractory, accutane.

Question 37

what is severe acne vulgaris charactreized by and what are the treatment options?

Answer 37

pustules, papules, dermal cysts leaving scars, open and closed comedomes. treatment is systemic retinoic acid( acutane)