Dermatology

Question 1

Layers of epidermis

Answer 1

From surface to base:

• stratum corneum (keratin-containing)
• stratum lucidum
• stratum granulosum
• stratum spinosum (desmosome containing)
• stratum basale (stem cell site)

Question 2

Zonula occludens

Answer 2

Tight junctions of skin. Prevent paracellular movement of solutes. Made of claudins and occludens. Most superficial connection of skin cells.

Question 3

Zonula adherens

Answer 3

Adherens junctions of skin. Cadherins connect actin cytoskeletons of adjacent cells. Deep to tight junction; superficial to desmosomes.

Question 4

Macula adherens

Answer 4

Desmosomes. Provide support by keratin interactions. Autoantibodies develop against them in pemphigus vulgaris.

Question 5

Gap junctions

Answer 5

Deepest cell-cell junction in skin. Connexons allow for electric and chemical communication between cells.

Question 6

Hemidesmosome

Answer 6

Connects keratin in basal cells to underyling basement membrane. Autoantibodies against them in bullous pemphigoid.

Question 7

Spongiosis

Answer 7

epidermal accumulation of edematous fluid in intercellular spaces

Question 8

Acantholysis

Answer 8

Separation of epidermal cells

Question 9

Acanthosis

Answer 9

Epidermal hyperplasia

Question 10

Albinism

Answer 10

Normal melanocyte number; decreased melanin production due to decreased tyrosinase activity or defective tyrosine transport. Also can be caused by failed nueral crest migration during development

Question 11

Melasma

Answer 11

Hyperpigmentation associated iwth pregnancy or OCP use

Question 12

Vitiligo

Answer 12

Irregular areas of depigmentation due to autoimmune destruction of melanocytes

Question 13

Atopic dermatitis

Answer 13

Same thing as eczema. Prurutic eruption on skin flexures. Starts on face in infancy; appears in antecubital fossae later

Question 14

Allergic contact dermatitis

Answer 14

Type IV hypersensitivity

Question 15

Melanocytic nevus

Answer 15

Regular mole. Intradermal are papular; junctional are flat

Question 16

Psoriasis

Answer 16

Papules and plaques with silvery scale. Acanthosis (epidermal hyperplasia) wither parakeratotic scaling (nuclei still in stratum corneum). Increased stratum spinosum; decreased stratum granulosum.

Question 17

Auspitz sign

Answer 17

Pinpoint bleeding spots from exposure of dermal papillae when scales scraped off seen in psoriasis.

Question 18

Rosacea

Answer 18

Inflammatory skin disorder with erythematous papules and pustules.

Question 19

Seborrheic keratosis

Answer 19

Flat, greasy, pigmented squamous epithelial proliferation. Look stuck on. Occur on head, trunk, extremities.

Question 20

Leser-Trelat sign

Answer 20

sudden apperance of multiple seborrheic keratoses; suggests underlying malignancy

Question 21

Impetigo

Answer 21

Superficial skin infection caused by S aureus or S pyogenes. Honey colored crusting. S aureus can cause bullae as well.

Question 22

Cellulitis

Answer 22

Infection of dermis and SC tissue. Usually S pyogenes or S aureus.

Question 23

Erysipelas

Answer 23

Inferction of upper dermis and superficial lymphatics. Usually strep pyogenes. Well-defined demarcation between infected and normal skin

Question 24

Abscess

Answer 24

Pus walled off within skin. Almost alwyas S aureus

Question 25

Necrotizing fasciitis

Answer 25

Deep tissue injury from anaerobes or S pyogenes. Causes crepitus. Bullae and purplish color to skin

Question 26

Staph scalded skin syndrome

Answer 26

Exotoxin destroys keratinocyte attachments in stratum granulosum. Fever, rash, skin sloughing

Question 27

Molloscum contagiosum

Answer 27

Papules caused by poxvirus (dsDNA, replicates in cytoplasm)

Question 28

Hairy leukoplakia

Answer 28

Irregular, white, painless plaques on tongue that can't be scraped off. Caused by EBV in immunocompromised patients.

Question 29

Pemphigus vulgaris

Answer 29

Potentially fatal. IgG against desmoglein in desmosomes. Flaccid intraepidermal bullae. Oral mucosa involved. Separation of epidermis on manual stroking of skin. Net-like apattern on IF.

Question 30

Bullous pemphigoid

Answer 30

IgG against hemidesmosomes. Tense blisters containing eosinophils on skin. Oral mucosa spared. Linear pattern on IF.

Question 31

Dermatitis herpetiformis

Answer 31

Pruritic papules, vesicles, bullae due to IgA deposits at tips of dermal papillae. Associatd with celica

Question 32

Erythema multiforme

Answer 32

Associated with infections, drugs, cancer, and autoimmune disease. Multiple types of lesions

Question 33

Stevens Johnson syndrome

Answer 33

Fever, bullae and necrosis, skin sloughing. High mortality rate. Adverse drug reaction

Question 34

Acanthosis nigricans

Answer 34

Epidermal hyperplasia causing hyperpigmented thickening of skin in axilla or neck. Associated with high insulin and visceral malignancies

Question 35

Actinic keratosis

Answer 35

Premalignant lesions caused by sun exposure. Small, rough, red or brown papules or plaques.

Question 36

Erythema nodosum

Answer 36

Painful inflammatory lesions of subcutaneous fat on anterior shins

Question 37

Lichen planus

Answer 37

Associated with hep C. Pruritic purple polygonal palmar papules and plaques. Wickham strae if mucosal involvement- reticular white lines.

Question 38

Pityriasis rosea

Answer 38

Patch followed by other scaly erythematous plaques in christmas ree distriution. Self-resolves in 6-8 weeks

Question 39

Basal cell carcinoma

Answer 39

Pink pearly nodules. Often with telangiectasias, rolled borders, central crusting or ulceration. Palisading nuclei

Question 40

Squamous cell carcinoma

Answer 40

Associated with immunosuppression. Face, lower lip, ears, and hands are most common spot. Ulcerative red lesions with frequent scale. Keratin pearls on histology. Actinic keratosis is precursor lesion.

Question 41

Melanoma

Answer 41

S-100 tumor marker. Depth of tumor correlates with risk of metastasis. Types: superficial spreading, nodular, lentigo maligna, acral lentiginous BRAF mutations common

Question 42

Types of bruises

Answer 42

Petechiae: pinpoint to pinhead (less than 5mm) bruises Purpora: 5mm to 1 cm Ecchymoses: over 1cm

Question 43

TGF beta

Answer 43

Stimulates connective tissue synthesis and remodeling of ECM. Persistently elevated in formation of keloid scars

Question 44

Ehlers-Danlos syndrome

Answer 44

Can be caused by procollagen peptidase deficiency, reuslting in impaired cleavage of terminal propeptides in ECM.

Question 45

Response to foreign body in a wound

Answer 45

Granulation tissue