Loco dermatology

Question 1

Keratin filament type

Answer 1

Intermediate

Question 2

Soft vs hard keratin

Answer 2

Soft = alpha helices 
Hard = beta sheets

Question 3

What links keratinocytes?

Answer 3

Desmosomes

Question 4

What joints basal keratinocytes to the BM?

Answer 4

Hemidesmosomes

Question 5

Cells in basal epidermis

Answer 5

Compact cells with dark nuclei

Stem cells that proliferative and migrate upwards

Question 6

Cells in spinous layer

Answer 6

3-4 cells thick

Spiny cells as many desmosomes

Question 7

Cells in granular layer

Answer 7

Dark purple cells

Stained due to keratohyaline granules that form substances that form protective barrier of the skin

Question 8

Cells in cornified layer

Answer 8

Flat cells with no nuclei or organelles

Question 9

Main cell type of the dermis

Answer 9

Fibroblast

Question 10

3 layers of dermis

Answer 10

Papillary = below BM with disorganised arrangement of collagen fibres 
Reticular = thick layer where collagen is more organised 
Adipose = made of adipose tissue = hypodermis

Question 11

Parts of the hair follicle

Answer 11

Dermal papilla = fibroblasts controlling hair growth
Bulb = matrix keratinocytes make cells to make hair
Outer root sheath = basal cell layer around the edge
Bulge region = hair follicle stem cells that migrate downwards

Question 12

Stages of the hair cycle

Answer 12

Anagen = active = hair growing in length 
Catagen = regressive = hair follicle retracts
Telogen = resting = end of cycle

Question 13

Eccrine sweat gland

Answer 13

Regular sweat glands

Important for thermoregulation

Question 14

Apocrine sweat gland

Answer 14

Specialised sweat gland found in axilla and pubic regions

Odourless sweat produced that then is digested by bacteria to make it smell

Question 15

Melanocytes

Answer 15

Dendritic cells of the epidermis

Project to keratinocytes and inject melanin to give pigment

Question 16

Langerhans cells

Answer 16

APCs of the skin

Mainly in basal and spinous layers of epidermis

Question 17

Merkel cell

Answer 17

Found in basal layer

Sense fine tough

Question 18

Mast cell

Answer 18

Found in dermis
Important for allergic responses
Secrete histamine

Question 19

Phases of wound healing

Answer 19

Inflammation = blood clot and recruitment of immune cells
Proliferation = keratinocytes and fibroblasts proliferate to form new skin 
Maturation = remodelling of skin to improve structure

Question 20

Risk factors for chronic wounds

Answer 20

Diabetes
Venous disease
Bedridden

Question 21

Th1 response

Answer 21

Intracellular bacteria or viruses

Question 22

Th2 response

Answer 22

Allergens, parasites

Question 23

Th17 response

Answer 23

Extracellular bacteria and fungi

Question 24

Dust mite allergy

Answer 24

Allergy to Der P1 wound in faecal pellets of dust mites

Question 25

Hives vs acute angioedema

Answer 25

``` Hives = epidermis only Angioedema = also dermis and subcutaneous tissues ```

Question 26

Where does angioedema occur?

Answer 26

Lower lips Eyes Pharyngeal mucosa

Question 27

Mechanisms of cell death in type 2 hypersensitivities

Answer 27

Complement dependent cytotoxicity Anti-body dependent cell mediated cytotoxicity Phagocytosis by macrophage Receptor blockade

Question 28

Pemphigus vulgaris

Answer 28

Development of IgG antibodies against desmoglein in desmosomes Leads to skin blistering = acantholysis Diagnosis = incubation --> chicken wire appearance Treatment = steroids, rituximab

Question 29

Cascade of contact allergic dermatitis

Answer 29

Skin exposed to allergen Langerhans cells take antigen to lymph node Activation fo T cells and memory formed Upon challenge --> activation and immune response

Question 30

Types of giant cells

Answer 30

Langham's = peripheral nuclei | Foreign body = random nuclei

Question 31

Alopecia areata

Answer 31

Antibodies against follicle Exclamation mark hairs Hair regrowth is white

Question 32

Viteligo

Answer 32

Antibodies against melanocytes | Skin loses pigmentation

Question 33

Staphylococcus vs streptococcal skin infections

Answer 33

Staphylococcal found on 20% of people Streptococcal rarely found on skin Staph infections more common Strep infections more severe

Question 34

Folliculitis

Answer 34

Infection of hair follicle

Question 35

Impetigo

Answer 35

Infection of epidermis By strep or staph Tx = topical ABx

Question 36

Cellulitis

Answer 36

Infection of dermis and subcutaneous fat More commonly due to streptococcus but also due to staphylococcus Oral ABx required

Question 37

Staphylococcal scalded skin syndrome

Answer 37

Toxins from bacteria lead to desquamation of the skin

Question 38

Toxic shock syndrome

Answer 38

Staphylococcal toxins cause severe systemic illness | From keeping tampons in too long

Question 39

Nectrotising fasciitis

Answer 39

Infection that leads to soft tissue death Most common cause = MRSA Treatment = debridement and BSABx

Question 40

Reasons for deterioration in eczema patients

Answer 40

Herpes simplex | Staphylococcus

Question 41

Molluscum contagiosum

Answer 41

Viral infection | Leads to small umbilicated lesions

Question 42

Tinea vesicolour

Answer 42

Pityriasis vesicolour Yeast overgrowth leads to hypo/hyperpigmentation Pathogen = Malassezia furfur

Question 43

Tinea corporis

Answer 43

Fungal infection | Ring shape structures

Question 44

Scabies

Answer 44

Severe itchy skin No history of eczema Skin-skin contact Pimple like rash