19. Skin Pathoma

Question 1

What are the layers of the epidermis? from surface to deep. what are found in each

Answer 1

Stratum Corneum (keratin)

Lucidum

Granulosm

Spinosum (desmosomes)

Basale (stem cells)

Question 2

Whats atopic dermatitis?

where does it usually appear?

what type of hypersensitivity?

Answer 2

aka Eczema

face and flexor surfaces

TYPE I

Question 3

Contact Dermatitis

what type of hypersensitivity

tx?

Answer 3

Poison Ivy, Nickel, neomycine

Type IV (delayed)

-remove offending agent/topical steroids

Question 4

Acne

whats it due to?

what type of infection

tx?

Answer 4

comedones (white heads and black heads), pustules (pimples)

Chronic inflammation of the hair follicles and sebacious glands

Proprionibacterium acnes (P. acnes)

-retinoids, benzoyl peroxide, antibiotics

Question 5

Psoriasis

whats it look like/ where is it found

whats another clinical sign it can be found with?

whats Auspitz sign?

tx?

Answer 5

excessive keratin proliferation: Parakeratosis (nuclei still in Stratum Corneum)

well-circumscribed “salmon colored” plaques with silvery scales

• extensor surfaces and scalp
• nail pititng

Auspitz: pinpoint bleeding after removing a scale

-corticosteroids/

Question 6

Lichen Planus

how does histo look?

which other infection is it associated with?

Answer 6

Pruritic, purple, polygonal planar papules and plaques

• Sawtooth infiltrates of Lymphocytes at dermal-epidermal junciton
• Hep C

Question 7

Pemphis Vulgaris

whats histo like? what layer is messed up

whats the clinical sign/finding?

what does immunoflourescence look like?

which type of skin does it involve?

Answer 7

Autoimmune destruction of Desmosomes via IgG antibodies

-tombstone appearance since basment cells are intact while the Stratum Spinosum is fucked up

• Separation of epidermis upon touching the skin (wet blisters)
• Net-like
• skin and oral mucosa

Question 8

Bullous Pemphigoid

what will immunoflourescene look like?

how do the blisters look?

Answer 8

Autoimmune Destruction of Hemidesmosomes via IgG antibodies

-Linear pattern

oral mucosa isnt affected

-Tense Blisters that dont rupture easily

Question 9

Dermatitis Herpetiformis

what do the lesions look like?

what dz is associated?

how do you treat it?

Answer 9

Depositions of IgA at tips of dermal papillae.

• -*herpes; so tiny vesicles that are grouped together
• Celiac dz

-dapsone/gluten free diet

Question 10

Erythema Multiforme

what kind of skin lesions?

what are some associations?

Answer 10

Hypersensitivity reaction w/ Target Lesions

-HSV, M. pnuemo, sulfa drugs

Question 11

Steven Johnson Syndrome

whats TEN?

Answer 11

Erythema Multiforme w/ oral mucosa and Fever

-Toxic epidermal necrosis: Sloughing off of the skin

Question 12

Sborrheic Keratosis

whats it called when you have a sudden appearance of these?

Answer 12

morgan freeman, looks stuck on

Leser-Trelat sign: sudden onset, usually a sign of malignancy (usually GI)

Question 13

Acanthosis Nigricans

(thick epidermis) (dark)

what is it? where is it usually found?

what causes/associated with it?

Answer 13

Thickening of the skin

usually on the groin or axilla

-diabetes, obesity, cushings, malignancy

Question 14

Basal cell carcinoma of the skin

what are the risk factors?

whats it look like?

whats a key finding on histo?

tx

Answer 14

most common skin cancer

• exposure to UV sunlight
• raised lesion/central ulcer/dilated blood vessels (telangiectasias)
• palisading nuclei
• tx: excision

Question 15

Squamous cell Carcinoma of the skin

what are some risk factors?

where is it usually found?

tx

whats usually its precursos

Answer 15

malignant proliferation of squamous cells

• sunlight, immunosupression, arsenic
• LOWER LIP
• excision
• Actinic keratosis

Question 16

Actinic Keratosis

Answer 16

precursor to squamous cell

Question 17

Keratoacanthoma

Answer 17

well differentiated SCC

volcanic lesion that forms quickly and resolves quickly as well

Question 18

what level in the skin are mealoncytes found?

what embryo structure is it derived from?

where does it synthesize melain?

Answer 18

in the Basal cells

• neural crest
• synthesizes melanin in the melanosome

Question 19

Vitiligo

Answer 19

Autoimmune destruction of the melanocytes

• localized loss of skin pigmentation

Question 20

Albinism

whats the enzyme defect?

what are the 2 types?

what can it lead to?

Answer 20

Congenital lack of pigmentation

–defect in Tyrosine transport (impairs melanin production)

• eyes or eyes/skin
• increased risk of skin cancer

Question 21

why are freckles present/darker than rest of skin?

Answer 21

they have increased number of melanosomes in their cells

Question 22

whats Melasma?

Answer 22

hyperpigmentation of the cheeks associated with pregnancy or OCP use

Question 23

Nevus (moles)

whats a junctional nevus?

Answer 23

Junctional: increased melanocytes at dermal-epidermal junction. these guys are Flat

Question 24

Melanoma

subtypes: nodular/lentiginous/acral

Answer 24

Malignant neoplasm of melanocytes

most common cause of Death in skin cancer

nodular: bad prognosis, creates huge bump
lentignious: good prognosis (radial prolif along the dermal epidermal junction)
acral: on the hands and feet of dark skinned ppl

Question 25

Impetigo

Answer 25

skin infeciton caused by SA and Strep pyogenes

Honey colored crusting

Question 26

Cellulitis

risk factors?

Answer 26

deep skin infection (bacteria to the dermis

red, tender swollen rash

-trauma, bug bite, surgery

Question 27

Necrotizing fasciitis

Answer 27

Necrosis of Subcutaneous tissue below the dermis

caused by anaerobic flesh eating bacteria

produciton of CO2 leads to crepitus

Question 28

Staph scalded skin syndrome

difference between this and TEN (toxic epidermal necrosis)

Answer 28

Exotins A&B destroy keratinoctye attachments in stratum granulosom from rest of skin

• sloughing of skin with rash and fever
• TEN has separation at the dermal-epidermal junction where as SSS is stratum granulosom