Visual Skin Library - Professional Edition Flashcards

Comprehensive practice flashcards detailing skin anatomy, physiology, clinical typing, analysis, dermatological disorders, cosmetic actives, treatment-room protocols, and safety standards from the Visual Skin Library.

According to skin anatomy fundamentals, what percentage of total body weight, surface area, and thickness range does the skin represent in an adult?

The skin accounts for approximately $16\%$ of body weight, has a surface area of $1.5\text{ to }2\,\text{m}^2$ in an adult, and has a total thickness of $0.5\text{ to }4\,\text{mm}$ depending on the body area.

What are the four primary types of cells found in the epidermis and their respective functions?

1. Keratinocytes: Make up $90\%$ of cells and produce keratin.
2. Melanocytes: Produce melanin (protective pigment).
3. Langerhans cells: Provide immune surveillance.
4. Merkel cells: Sense light touch.

What are the five layers of the epidermis from the surface down to the base?

Stratum corneum, stratum lucidum (present only on palms and soles), stratum granulosum, stratum spinosum, and the basal layer.

How do the papillary dermis and reticular dermis differ in structure and function?

The papillary dermis is a thin upper layer with fine, loose fibers and rich blood vessels that nourishes the epidermis. The reticular dermis is a thick, deep layer with dense, organized fibers that provides mechanical strength and houses follicles and glands.

What are the key differences between eccrine and apocrine sweat glands?

Eccrine glands are distributed all over the body ($2\text{ to }4\text{ million}$ glands), produce watery/salty sweat ($99\%$ water), open directly onto the skin, and regulate temperature. Apocrine glands are located in the armpits, groin, and areolas, produce thick sweat containing proteins and lipids, open into the hair follicle, and activate at puberty.

What are the four anatomical parts of the pilosebaceous follicle?

The ostium (surface pore opening), the infundibulum (upper canal where comedones form), the sebaceous gland (releases sebum into the canal), and the bulb and papilla (base where hair originates and receives nourishment).

How is the skin barrier organized according to the 'bricks and mortar' model?

The 'bricks' are corneocytes (dead cells filled with keratin), the 'mortar' consists of intercellular lipids (ceramides, cholesterol, and fatty acids), the 'rivets' are corneodesmosomes holding cells together, and NMF (Natural Moisturizing Factor) resides inside the cells to trap water.

What is the normal physiological pH range of healthy skin compared to common bar soaps?

Normal skin pH is slightly acidic at $4.5\text{ to }5.5$, whereas many bar soaps have an alkaline pH of $9\text{ to }10$.

What is the average epidermal cell renewal cycle time in a young adult versus an adult after age $50$?

The average renewal cycle is $28\text{ days}$ in a young adult, slowing to $40\text{ to }45\text{ days}$ after age $50$.

What is the approximate chemical composition of the skin's Natural Moisturizing Factor (NMF)?

$40\%$ Free amino acids, $12\%$ Pyrrolidone carboxylic acid (PCA), $12\%$ Lactates, and $7\%$ Urea.

What are the two types of melanin produced during melanogenesis, and how do they differ?

Eumelanin is brown and black, provides superior UV protection, and is dominant in dark skin. Pheomelanin is red and yellow, provides less UV protection, and is dominant in fair skin and redheads.

What are the normal core body temperature and the usual skin surface temperature?

Normal core body temperature is approximately $37\,^\circ\text{C}$ ($98.6\,^\circ\text{F}$), while usual skin surface temperature ranges from $32\text{ to }34\,^\circ\text{C}$ ($90\text{ to }93\,^\circ\text{F}$).

What is the primary lipid composition of human sebum?

$57\%$ Triglycerides and fatty acids, $26\%$ Wax esters, and $12\%$ Squalene.

What are the four sequential phases of wound healing and their timeframes?

1. Hemostasis: Occurs within minutes (clot formation).
2. Inflammation: Days $1\text{ to }4$ (wound cleaning).
3. Proliferation: Days $4\text{ to }21$ (new tissue formation and closure).
4. Remodeling: Lasts up to $1\text{ year}$ (collagen reorganization).

What are the four classic signs of cutaneous inflammation?

Redness (erythema), Heat (elevated local temperature), Swelling (puffiness/edema), and Pain or burning sensation.

What is the fundamental difference between dry skin and dehydrated skin?

Dry skin is a genetic, stable skin type characterized by alipic deficiency (lack of sebum and lipids). Dehydrated skin is a temporary skin condition characterized by a lack of water that can affect any skin type, including oily skin.

How does sensitive skin differ clinically from sensitized skin?

Sensitive skin is a lifelong, genetically predisposed state. Sensitized skin is an acquired, temporary condition caused by barrier damage, frequently triggered by product overuse, aggressive exfoliants, or chemical peels.

Under a Wood's lamp examination at a distance of $10\text{ to }15\,\text{cm}$, what do the colors blue-violet, white, dark violet, orange/pink, and brown signify?

• Blue-violet: Normal skin
• White: Thickened horny layer
• Dark violet: Dehydrated skin
• Orange or pink: Sebum and comedones
• Brown: Superficial pigment

What are the four classifications of photoaging defined by the Glogau Scale?

• Type I: No wrinkles (typical ages $20\text{ to }30$, minimal spots)
• Type II: Wrinkles in motion (typical ages $30\text{ to }40$, early spots)
• Type III: Wrinkles at rest (age $50\text{ and up}$, visible spots)
• Type IV: Only wrinkles (age $60\text{ and up}$, yellowish skin)

How are primary skin lesions distinguished from secondary skin lesions, and what are examples of each?

Primary lesions are physical changes caused directly by a disease process: Macule (flat spot), Papule (raised bump $< 1\,\text{cm}$), Pustule (raised pus-filled bump), Nodule (deep palpable lesion), and Vesicle (small fluid-filled blister). Secondary lesions result from evolution, trauma, or manipulation: Scale (flaking skin), Crust (dried exudate), Scar (fibrous tissue repair), and Erosion (superficial epidermal loss).

What percentage of solar UV radiation reaching the Earth's surface is UVA, and how do UVB and UVA differ in penetration?

$95\%$ of UV radiation reaching Earth is UVA. UVB penetrates only to the epidermis causing sunburn and direct DNA damage, whereas UVA penetrates deeper into the dermis causing photoaging and pigmentation changes all year round.

What are the distinguishing diagnostic differences between sun spots (solar lentigines) and freckles (ephelides)?

Sun spots are caused by accumulated sun exposure, appear in adulthood (commonly after $40$), measure from a few millimeters up to $1\text{ to }2\,\text{cm}$, and do not fade in winter. Freckles are small ($1\text{ to }5\,\text{mm}$), genetic spots appearing in childhood on fair skin that darken in summer and fade in winter.

What are the three distinct clinical types of dark eye circles and how can they be differentiated?

1. Pigmented: Brown color common in darker phototypes; color remains unchanged when stretched.
2. Vascular: Blue or purplish tone due to thin skin; color diminishes or disappears when the skin is stretched.
3. Structural/Shadow: Caused by a hollow tear trough; color changes under varying lighting angles.

What are the four interconnected pathogenetic factors that form acne?

1. Excess sebum production (androgen-mediated)
2. Follicular hyperkeratinization (canal obstruction)
3. Bacterial proliferation (Cutibacterium acnes)
4. Cutaneous inflammation

What are the clinical characteristics of the four acne grades?

• Grade I: Comedones with minimal inflammation
• Grade II: Papules and some pustules with moderate inflammation
• Grade III: Numerous pustules and some nodules with mark risk
• Grade IV: Severe nodules and cysts with high scarring risk (requires medical referral)

What are the three morphology types of atrophic acne scars?

1. Icepick: Narrow, deep pits
2. Boxcar: Depressions with sharply defined, steep edges
3. Rolling: Broad depressions with an undulating, wavy surface

What percentage of visible facial aging is attributed to solar exposure?

Approximately $80\%$ of visible facial aging is attributed to UV sun damage (photoaging).

What percentage of dermal collagen is lost in women during the first five years following menopause?

Approximately $30\%$ of skin collagen is lost in the first $5\text{ years}$ of menopause due to declining estrogen levels.

What is keratosis pilaris, and which active cosmetic ingredients are indicated for it?

Keratosis pilaris is a harmless genetic condition marked by follicular hyperkeratosis that produces small, rough bumps on the arms, thighs, and buttocks. Useful actives include Urea ($10\%$), lactic acid, salicylic acid, and rich emollients.

How does milia differ from a closed comedone in composition, texture, and extraction technique?

Milia are small, hard, pearly white inclusions of encapsulated keratin with no visible pore opening; they require a sterile disposable lancet to open. Closed comedones are softer, skin-colored bumps of trapped sebum and dead cells inside a follicle canal.

What criteria comprise the ABCDE rule for assessing pigmented lesions and moles?

• A: Asymmetry
• B: Border irregularity
• C: Color variation (several colors)
• D: Diameter greater than $6\,\text{mm}$
• E: Evolving or changing size, shape, or color

What is the relative potency hierarchy of retinoids from mildest to strongest?

Retinyl esters (mildest cosmetic) < Retinol (effective cosmetic) < Retinal (faster cosmetic) < Tretinoin / retinoic acid (strongest, prescription only).

What are the distinct chemical origins and properties of glycolic, lactic, and mandelic acids?

• Glycolic acid: Derived from sugar cane; smallest molecular size, deepest penetration.
• Lactic acid: Derived from milk; exfoliates while simultaneously acting as a humectant.
• Mandelic acid: Derived from bitter almonds; largest molecular size, slow gentle penetration, ideal for sensitive skin and darker phototypes.

What is the optimal physiological ratio of barrier replacement lipids in cosmetic formulations?

An equimolar ratio of $3:1:1$, consisting of $3\text{ parts}$ ceramides, $1\text{ part}$ cholesterol, and $1\text{ part}$ free fatty acids.

What are the four peel depth levels, anatomical penetration depths, and permitted practitioners?

1. Very superficial: Horny layer (performed by estheticians)
2. Superficial: Epidermis (performed by estheticians)
3. Medium: Papillary dermis (performed by doctors)
4. Deep: Reticular dermis (performed by doctors)

What are the operational differences in application and neutralization between glycolic and salicylic acid peels?

Glycolic peels ($20\text{ to }35\%$, $1\text{ to }3\,\text{min}$ starting time) require chemical neutralizer application when erythema or stinging occurs. Salicylic acid peels ($20\text{ to }30\%$, $3\text{ to }5\,\text{min}$) are self-neutralizing, do not require a neutralizing solution, and precipitate white crystals on the skin surface that are rinsed with water.

What is the recommended blade angle and stroke direction for dermaplaning?

The sterile disposable blade must be held at a $45^\circ$ angle against taut skin, utilizing short, controlled strokes in the direction of hair growth.

What are the five classical movements of facial massage and their physiological benefits?

1. Effleurage: Gentle gliding strokes to relax and spread product.
2. Petrissage: Kneading manipulation that tones muscles.
3. Friction: Circular deep movements to stimulate microcirculation.
4. Tapotement: Rhythmic tapping that stimulates nerve endings.
5. Vibration: Trembling movements that promote muscle relaxation.

What is the required hand washing duration for infection control in the treatment room?

Scrubbing hands (palms, backs, fingers, and nails) with soap and water for a minimum of $40\text{ to }60\,\text{seconds}$, followed by drying with a single-use disposable towel.

What are the differences between cleaning, disinfection, and sterilization?

Cleaning removes visible dirt using water and detergent. Disinfection kills most pathogenic microorganisms using agents like $70\%$ alcohol or quaternary ammonium (for surfaces and non-critical tools). Sterilization completely eradicates all forms of microbial life using an autoclave (mandatory for critical instruments that cut or penetrate the skin).

How long must an esthetician wait before performing peels or waxing on a client who has taken oral isotretinoin?

A waiting period of at least $6\text{ months}$ after completing oral isotretinoin therapy is required before performing chemical peels or waxing.

What is the protocol for administering a cosmetic patch test?

Apply a small amount of product to the inner forearm or behind the ear, leave it for $48\text{ to }72\,\text{hours}$, and observe for signs of erythema, pruritus, edema, or urticaria.

What are the post-procedure restrictions regarding direct sun exposure, exfoliative actives, and makeup?

Avoid direct sun exposure for at least $7\text{ days}$, discontinue retinoids and exfoliating acids for $5\text{ to }7\text{ days}$, and avoid makeup application for the first $24\,\text{hours}$.