L2 - Intro to Derm Flashcards
Layers of the Skin
-
Epidermis
- Barrier from environment
- Waterproof
-
Dermis
- Blood vessels, hair follicles, sebaceous glands, sweat glands, nails, apocrine glands
-
Subcutaneous (Hypodermis)
- Subcutaneous fat and connective tissue
Epidermis: Layers
What are the layers of the epidermis?
-
Stratum corneum
- Superficial layer with shedding dead skin
-
Stratum lucidum
- Layer found on palmar and plantar surfaces
-
Stratum granulosum
- Keratinization
-
Stratum spinosum
- Spiny-shaped cells (strength and flexibility)
-
Stratum basale
- Cells germinate: keratinocytes
Epidermis: Cell types
What types of cells are found in the epidermis?
- Keratinocytes
- Melanocytes
- Merkel cells
- Langerhans cells
Dermis
What is the function of the dermis?
What are the layers of the dermis?
-
Function
- Support structure that contains blood and lymphatic vessels, nerves, hair follicles, glands and fibrous tissue
- Provides flexibility, strength and contains sensation
-
Layers
-
Papillary dermis (superficial dermis)
- Comprised of a loose network of fine collagen bundles
-
Reticular dermis (deep dermis)
- Comprised of densely packed and thick collagen bundles
- Ground substance
-
Papillary dermis (superficial dermis)
Hypodermis (subcutis)
What makes up the hypodermis?
- Fibroblasts, adipose and macrophages
- Subcutaneous fat
- Deepest layer
- Network of collagen and fat cells
- Conserves heat
- Contains larger vessels and nerves
Anatomy of the skin
What are the appendages of skin?
- Hair
- Nails
- Sebceous glands
- Sweat glands
- Eccrine
- Apocrine
Eccrine Glands
Where are they located?
What do they do?
- Covers most of the body
- Abundant on the palms, soles and forehead
- Releases salt and water to keep the body cool
- Does not cause odor
- Duct opens in pore at skin’s surface
Apocrine Glands
Where are they located?
What do they secrete?
Triggers?
- Concentrated in axillary and genital regions
- Secretes into the sac of hair follicles
- Releases thick clear odorless fluid
- Bacteria that live on the skin break down apocrine secretions, which leads to body odor
- Triggered by nervous system
- Stress, exercise, hormones, emotions
Hair Follicles
Vellus hairs: What are they? Where are they located?
Terminal hairs: What are they? Where are they located?
Bulb: What is it?
-
Vellus hairs
- Short and fine (forehead)
-
Terminal hairs
- Long and thick (scalp/axillae)
-
Bulb
- Enlargement at the base of follicle
- Matrix cells at inferior aspect of bulb
- Melanocytes within matrix contribute to pigment
Physiology of the Skin
What is the function of the skin?
- Protect from trauma and infection
- Prevent fluid loss
- Regulate body temperature
- Provide sensory information
- Produce vitamin D
Morphology of Skin Lesions
What is morphology?
- Morphology refers to how dermatologists describe forms and structure of skin lesions
- Key for diagnosis
- This is important when presenting to your preceptor
- To arrive at the right description, you will need to perform:
- Visual inspection
- Tactile inspection
Morphologic Characteristics of Skin Lesions
What are the morphologic characteristics?
- Distribution
- Shape / arrangement
- Border / margin
- Pigmentation / color
- Palpation
Morphological Characteristics of Skin Lesions
Distribution
What are the different distributions?
What is an example of each?
Localized
- Lesions appear in one small area
- Ex: Herpes Simplex Virus (HSV)
Regional
- Lesions appear in a specific region of the body
- Ex: Atopic dermatitis on flexor surfaces
- Ex: Psoriasis on extensor surfaces
Generalized/disseminated
- Lesions appear widely distributed or in multiple areas simultaneously
- Ex: Chickenpox (Varicella-Zoster Virus)
Morphologic Characteristics of Skin Lesions
Shape/Arrangement
What are the different shapes/arrangements?
What is an example of each?
-
Round/discoid
- Coin shaped
- No central clearing
- Seen with eczema
- Umbilicated lesions
-
Oval
- Ovoid
- Ex: Pityriasis rosea
-
Annular
- Round
- Active margins with central clearing
- Ex: Seen in tinea infections
-
Dermatomal
- Following a nerve segment
- Ex: Herpes or Varicella Zoster
-
Target
- Pink macles with purple central papules
- Ex: Erythema Multioforme
-
Linear
- Phytophotodermatitis
-
Serpiginous
- Cutaneous larva migrans
-
Morbilliform
- Measles-like
- Erythematous maculopapular lesions that become confluent on the face and body
Morphological Characteristics of Skin Lesions
Borders/Margins
What are the types of borders/margins?
What is an example of each?
-
Distinct
- Well-demarcated or defined
- Able to draw a line around the area with confidence
-
Indistinct
- Poorly defined
- Borders merge with normal skin
-
Irregular
- Ex: Malignant melanoma
-
Raised
- Center of lesion is depressed compared to the edge
- Ex: basal cell carcinoma
Morphological Characteristics of Skin Lesions
Color/Pigmentation
What are the types of colors/pigmentations observed?
What is an example of each?
- Flesh colored
- Same color as surrounding skin
- Erythematous
- Variable shades of red: pink, salmon, coppery, reddish-blue
- Violaceous
- Light violet
- Tan-brown
- Black or blue-black
- Blue nevus
- Hyperpigmented / Hypopigmented
Morphological Characteristics of Skin Lesions
Palpation of Lesions
Whata are you feeling for?
- Consistency
- Mobility
- Blanchable
- An erythematous lesion that loses all redness when pressed
- Diascopy (test for blanchability)
- Tenderness
- Depth of lesion
- Deviation in temperature
- Fluctuant
ABCDs of Melanoma
-
A – asymmetry
- If cut in half, sides should mirror each other (doesn’t in melanoma)
-
B – borders
- Irregular
-
C – color
- Variegated
-
D – diameter
- >6mm
-
E – evolution or elevation
- Most important to assess with patient
- Has it changed in shape/size color
Primary vs. Secondary Lesions
What do they arise from?
What are secondry lesions caused by?
-
Primary Lesions
- Arise from previously normal skin
- Key to diagnosis
-
Secondary Lesions
- Arise from changes in primary lesions
- Usually due to exogenous factors / changes
- i.e.: scratching, infection, rubbing, crusting, etc.
Primary Lesions:
Circumscribed, flat, nonpalpable
Macule vs. Patch
Primary lesions
Superficial elevations by free fluid
Vesicle
Bulla
Pustule
Primary lesions:
Palpable, elevated, solid masses
Papule
Plaque
Nodule
Tumor
Wheal
Furuncle vs. Carbuncle
what are they?
Cause?
- Furuncle (aka: boil)
- Infection of single hair follicle
- S. aureus
- Carbuncle
- Infection of multiple hair follicles
- S. aureus
- Can form an abscess
Secondary Lesions:
Material on the skin surface
Crust
Scale
Secondary Lesions:
Loss of skin surface
Fissure
Erosion
Ulcer
Secondary Lesions:
Miscellaneous lesions
Excoriation
Atrophy
Lichenification
Vascular lesions:
Petechiae vs. Purpura
Distribution
Shape/ Arrangement
Border
Color
Palpation
Size
Vascular Lesions:
Ecchymosis vs. Spider Angiomas
Distribution
Shape/ Arrangement
Border
Color
Palpation
Size
Vascular Lesions:
Cherry angiomas vs. Telangiectasias vs. Hemangioma
Distribution
Shape/ Arrangement
Border
Color
Palpation
Size
Categories of Skin Disease
What are the categories of skin disease?
Papulosquamous
Nodular
Vesiculobullous
Maculopapular
Categories of Skin Disease
Papulosquamous Lesions
Categories of Skin Diseases: Lichen Planus
What type of skin disease?
What are the 5 P’s?
- Papulosquamous
- The 5 P’s
- Pruritic
- Polygonal
- Purpl
- Planar
- Papules
Categories of Skin Disease: nodular lesions
What are they?
Cause?
Examples?
- Nodular Lesions - Benign and malignant epidermal and dermal nodes
- Benign
- Nevi, cherry angiomas, epidermiid cyst
- Malignant
- Squamous Cell carinoma (SCC)
- Basal Cell Carcinoma (me
- Benign
- Benign and malignant epidermal and dermal nodes
Categories of skin lesions: Vesiculobullous Lesions
*
Categories of Skin Lesions: Vesiculobullous Lesions
- Examples:
- Impetigo
- Herpes
- Pemphigus
Categories of Skin Lesions: Vesiculobullous Lesions
- Macules and papules
- Examples:
- Viral exanthems
- Generalized, erythematous,
- maculopapular rash
- Drug eruptions
Nail Disorders
Clubbing
- Rounded, bulbous nail base
- Feels spongy
- How to Diagnose
- Flex the fingers of both hands
- Bring index fingers together until distal phalanxes are touching
- Diamond space between nails indicates no clubbing
Nail Disorders
Beau’s Lines
- Transverse depressions secondary to trauma or acute or severe illness
- Lines grow out with the nail
Nail Disorders
Paronychia
What is it?
Acute vs chronic
- Inflammation of the proximal and lateral nail folds
- Acute (< 6 weeks)
- Chronic (> 6 weeks)
Nail Disorders
Onychocryptosis
- Ingrown toenail
- Usually involving the large toe
- Very common
- Nail grows into the dermis
- +/- pain
- Can become infected
Nail Disorders
Terry’s Nails
- Mostly white with a distal band of reddish brown
- Characteristic “ground glass” appearance
- Without any lunula
Nail Disorders
Leukonychia
- Trauma to nails causing areas of white discoloration
Nail Disorders
Koilonychia
- “Spoon Nail”
- Spoon shaped, concave nail
Nail Disorders
Onycholysis
- Painless separation of the nail plate from the nail bed
Nail Disorders
Onychomycosis
- Fungal infection of nail bed, plate or matrix
- Common with increased age
Nail Disorders
Nail Pitting
- Small punctate depressions
- Caused by nail matrix inflammation
