1 - Epidermis and Derm Terms

Question 1

Describe the Epidermis? What is its function?

Answer 1

Derived from ectoderm, outermost layer of the skin, barrier function.

Question 2

What are the layers of the epidermis from superficial to deep?

Answer 2

1. Stratum corneum
2. Stratum granulosum (granular layer)
3. Stratum spinosum
4. Stratum Basale

Question 3

Describe the basay layer (stratum basale) of the epidermis?

Answer 3

Deepest layer, attached to the basement membrane, contains keratinocyte stem cells.

Also contains transient amplifying cells (TA) which are kind of like stem cells but divide a bunch and then become spinous cells.

Question 4

Describe the stratum spinosum (spinous layer) of the epidermis?

Answer 4

Second deepest layer, composed of differentiating keratinocytes.

In most parts of the body it makes up most of the epidermis.

Synthesizes keratin.

*Spiney looking because of desmosome junctions*

Question 5

What are the five types of junctions of the epidermis?

Answer 5

1. Tight junctions: connection with actin
2. Adherens junctions
3. Desmosomes: contain keratins
4. Focal adhesions
5. Hemodesmosomes: one part of the desmosome

Question 6

Describe the structure of keratin intermediate filaments?

Answer 6

They help connect cells

Question 7

Describe the assembly of intermediate filaments?

Answer 7

Two rod domans of keratin form a heterodimer.

Two heterodimers form a tetramere.

Tetrameres lines up to form a protofilament, and several protofilaments becasue the intermediate filament.

Question 8

What are the two types of granules in the stratum granulosum (granular layer)?

Answer 8

Keratohyalin granules and Lamellar granules (Odland bodies)

Question 9

What are the keratohyalin granules in the stratum granulosum (granular layer)?

Answer 9

Filaggrin, involucrin, loricrin

Question 10

What are the lamellar granules (odland bodies) in the stratum granulosum (granular layer)?

Answer 10

Tend to be made of fat.

Ceramides, cholesterol, fatty acids, hydrolytic enzymes

Question 11

What are the characteristics of the stratum cornuem (cornified layer)? Where is it the thickest and thinnest?

Answer 11

Composed of corneocytes: lack nucleus and organelles (dead), held together by corneodesmosomes.

Primary barrier of the epidermis with variable thickness:

• No corneum in the ora, genital, and ocular mucosa
• Thinnest on the face and genetals
• Thickest on the palms and soles

Question 12

What is keratinization?

Answer 12

The process of keratinocyte migration and maturation.

Average time is 28 days:

• stratum basale to stratum corneum > 14 days
• stratum corneum to shedding > 14 days

Question 13

Describe the “bricks and mortar” concept of how keratinocytes turn into corneocytes?

Answer 13

The keratohyalin granules will form the cornified envelope (“bricks”) of the corneocyte for strength and shape.

The lamellar granules serve as the lipid envelope (mortar) around the corneocytes.

Question 14

What is pemphigus vulgaris?

Answer 14

Acquired disease of the epidermis.

Autoimmune bullous disease involved auto-antibodies to desmosomal proteins (desmoglein 1 and 3). (desmosomes connect keratinocytes).

Results in intraepidermal blistering; just within the epidermis.

Question 15

What are clinical features of pemphigus vulgaris?

Answer 15

1. Flaccid, easily ruptured bullae
2. Oral and mucosal lesions
3. Nikolsky’s sign positive: rubbing on the skin by the blister causing it to shear off (pictured) due to loss of tight desmosomes holding it togehter

Question 16

What is the treament for pemphigus vulgaris?

Answer 16

• Prednisone
• Azathioprine
• Mycophenolate mofetil
• Rituximab

Question 17

What is Ichthyosis vulgaris? How common is it?

Answer 17

Autosomal dominant genetic condition

Mutations in profilaggrin gene that result in in a defective fillaggrin protein (this is what normally helps form the cornified later)

Affects 1 in 250

Question 18

What are clinical features of ichthyosis vulgaris? What are some associations?

Answer 18

• “Fish scales” especially on the shins
• Dry skin
• Hyperlinear palms

Associations: atopic dermatitis, allergic rhinitis, food allergies, asthma.

Question 19

Describe UV radiation? What are the different types?

Answer 19

UV radiation can be UVC, UVB, and UVA

UVC is filtered by the Ozone

UVA and UVB can penetrate our skin. UVB only goes to epidermis, UVA goes deeper into the dermis.

Question 20

What is the main source of UV? What are characteristics of UV light?

Answer 20

The sun; the highest levels are from 10am to 4pm and at high altitudes.

UV light is not visible, and can penetrate clouds, water, and glas.s

Question 21

What is the difference between physical sunscreen ingredients and chemical sunscreen ingredients?

Answer 21

Physical sunscreen ingredients: reflect and scatter UV light. Exp: titanium dioxide, zinc oxide.

Chemical sunscreen ingredients: absorb UV light. Exp. PABA, oxybenzone, avobenzone.

Question 22

What is SPF?

Answer 22

Sun protective factor (SPF) = MED protected / MED unprotected.

MED = Minimal erythema dose = minimum amount of UVB that causes skin redness at 24 hours.

*SPF only measures UVB protection!

Question 23

Is SPF 60 twice as effective as SPF 30? Describe the ideal sunscreen?

Answer 23

No, because the graph is exponential.

Ideal sunscreen: broad spectrum (UVA and UVB), water-resistant, SPF 30 or greater.

Question 24

What are some sunscreen application tips?

Answer 24

Apply 15 minutes before sun exposure

Apply generously: 1 oz (shot glass) for adult; most people apply 25-50% of recommended dose)

Reapply every 2 hours, or every 40-80 is swimming/sweating.

Reaply after towel drying.

Question 25

Describe a photoprotective regimen?

Answer 25

Sunscreens are only part of the regiment, avoid midday sun (10am-4pm) Seek shade Wear sun-protective hats/clothing.

Question 26

What is the definition of SPF?

Answer 26

SPF = MED protected / MED unprotected

Question 27

How would you describe a *flat*, *nonpalpable* primary lesion if it's less than 1 cm? What if it's \>1 cm?

Answer 27

\< 1 cm = macule \> 1 cm = patch

Question 28

How would you describe a *elevated or depressed, palpable* primary lesion if it's less than 1 cm? What if it's \>1 cm?

Answer 28

\< 1 cm = **papule** \> 1 cm = **plaque** (differs from nodule because of broad and flat surface). A **nodule** is palpable, \> 1 cm, but differs from plaques in that it has a rounded surface

Question 29

How would you describe a *fluid-filled blister* primary lesion if it's less than 1 cm? What if it's \>1 cm? What about a pus-filled blister?

Answer 29

\< 1 cm = vesicle \> 1 cm = bulla Pus-filled = pustule

Question 30

What is a wheal? What is it characteristic of?

Answer 30

Edematous papules and plaques that are characteristic of hives.

Question 31

Describe telangiectasia, purpura, and petechia. How do they differ?

Answer 31

**Telangiectasia:** dilated blood vessels (go away if you press on them) **Purpura:** area of hemorrhage; can be flat or elevated. Cannot make them go away with pressure. **Petechia:** pinpoint purpura; can't make go away with pressure.

Question 32

What two questions does the primary lesion answer?

Answer 32

Can I feel this? Is it more or less than a centimeter in size?

Question 33

Describe these *secondary* changes/lesions: scale, crust, lichenification.

Answer 33

**Scale:** accumulation of stratum corneum **Crust**: dried serum, pus, or blood **Lichenification:** epidermal thickening with accentuation of skin markings (exp. chronic eczema)

Question 34

Describe these *secondary* changes/lesions: excoriation, erosion, ulcer, fissure.

Answer 34

**Excoriation:** linear erosion caused by scratching **Erosion:** open area with partial or full loss of epidermic **Ulcer:** open area with loss of part of dermis **Fissure:** linear ulcer

Question 35

What shouldn't be done when describing the color of a skin defect?

Answer 35

**Do not use the word "erythematous" as it is not specific enough.** Use words like: link pink, brick red, hyperpigmented, hypopigmented, brown, tan, skin colored, violaceous, yellow-orange.

Question 36

If you're describing the configuration of a lesion, what does that mean?

Answer 36

The shape of an individual lesions or arrangement of multiple lesions.

Question 37

Define the following *configuration* descriptors for skin lesions: nummular, geographic, and polycyclic.

Answer 37

**Nummular:** coin-shaped (more oval than round) **Geographic:** Irregularly-bordered like a continent **Polycyclic:** multiple round lesions coalesced together

Question 38

Define the following *configuration* descriptors for skin lesions: serpiginous, annular, arcuate, and linear.

Answer 38

**Serpiginous:** wavy lines, worm-like **Annular:** ring-like with central clearing **Arcuate:** curved **Linear:** straight line

Question 39

Define the following configuration descriptors for skin lesions: targetoid, polygonal, reticulate or retiform, and stellate.

Answer 39

**Targetoid:** like a bulls-eye with at least 3 zones of color (annular only has 2) **Polygonal:** resembling a polygon **Reticulate or retiform:** net-like **Stellate:** star-shaped

Question 40

Define the following *distribution* descriptors for skin lesions: generalized, sun-exposed or photo-distributed, and acral.

Answer 40

**Generalized:** involving the entire body **Sun-exposed or photo-distributed:** on places that are typically exposed to the sun **Acral:** affecting distal limbs

Question 41

Define the following *distribution* descriptors for skin lesions: blaschkoid, dermatomal, and symmatrical?

Answer 41

**Blaschkoid:** following Blaschko's lines (exctodermal development lines) **Dermatomal:** following skin areas supplied by a single spinal nerve **Symmetrical:** equally affecting both sides of the body

Question 42

Define the following *distribution* descriptors for skin lesions: unilateral and intertriginous?

Answer 42

**Unilateral:** affecting only one side of the body **Intertriginous:** within body folds

Question 43

What word means "warty"?

Answer 43

Verrucous.