Master Esthetician cheat sheet

Skin analysis sequence: cleanse, magnify, palpate, Wood’s lamp, then document; each step informs the next treatment decision.

Exfoliation depth: stratum corneum (superficial), papillary dermis (medium), reticular dermis (deep); medium and deep peels require medical supervision in most jurisdictions.

Transepidermal water loss (TEWL) rises when barrier lipids are depleted; treat with ceramides, cholesterol, and fatty acids in a 1:1:1 molar ratio.

Fitzpatrick scale: I–III lighter, IV–VI darker; higher types have greater risk of post-inflammatory hyperpigmentation (PIH) after aggressive treatments.

Acne treatment ladder: topical retinoids, benzoyl peroxide, salicylic acid, azelaic acid; avoid aggressive extractions on inflamed cysts.

Rosacea triggers: heat, sun, spicy food, alcohol, stress; use gentle cleansers, metronidazole, azelaic acid, and broad-spectrum SPF.

Hydration vs. moisture: hydration refers to water content; moisture refers to oil content; humectants attract water, emollients seal it, occlusives block loss.

Treatment frequency for chemical peels: superficial every 2–4 weeks; medium peels every 4–6 weeks; assess barrier recovery before repeating.

Post-treatment care: avoid sun exposure, use gentle cleanser, moisturizer, and SPF 30+; do not pick or exfoliate until skin normalizes.

Alpha hydroxy acids (AHAs): glycolic (smallest, deepest penetration), lactic (hydrating), mandelic (large, gentle, good for darker skin), tartaric, citric.

Beta hydroxy acid (BHA): salicylic acid is lipophilic, penetrates pores, anti-inflammatory; useful for acne and oily skin.

Trichloroacetic acid (TCA) peel depths: 10–20% superficial, 25–35% medium, 40%+ deep; deep peels carry risk of scarring and cardiac arrhythmia.

Jessner’s solution: resorcinol, lactic acid, salicylic acid in ethanol; often combined with TCA for medium-depth peels.

Neutralization: AHAs require neutralization with sodium hydroxide or sodium bicarbonate; TCA self-neutralizes; BHA may require neutralization depending on formulation.

Frosting indicates protein coagulation; even white frost = medium depth; solid white = deeper; do not apply more acid over frosted areas.

Contraindications: active infection, open wounds, isotretinoin use within 6–12 months, pregnancy (avoid salicylic acid and high-dose retinoids), keloid history, recent waxing.

Post-peel reactions: erythema, stinging, flaking, and peeling are expected; blistering, intense pain, or scarring require medical referral.

Priming skin with retinoids or AHAs before peels can enhance penetration and risk; adjust peel strength accordingly.

Microdermabrasion uses aluminum oxide or sodium chloride crystals or a diamond-tip handpiece to abrade the stratum corneum; depth controlled by vacuum, speed, and passes.

Typical treatment interval: 2–4 weeks; 6–12 sessions for mild resurfacing; avoid over-treating to prevent barrier damage.

Contraindications: active acne, rosacea (vascular type), open lesions, recent chemical peel or laser, isotretinoin use, pregnancy (relative), keloid history.

Diamond-tip microdermabrasion is crystal-free, reducing risk of ocular or respiratory irritation; still requires eye protection.

Mechanical exfoliation includes scrubs, brushes, and dermaplaning; dermaplaning removes vellus hair and stratum corneum and must avoid active acne and bleeding disorders.

Post-treatment: soothe with cool compress, apply hydrating serum and broad-spectrum SPF; avoid retinoids and AHAs for 48–72 hours.

Infection control: single-use crystals or sterilized tips; clean handpiece between clients; follow manufacturer’s disinfection protocol.

Assess skin tolerance: lighter pressure on sensitive or thin skin; avoid bony prominences and areas with telangiectasia.

Selective photothermolysis: target chromophore (melanin, hemoglobin, water) absorbs specific wavelength; pulse duration shorter than thermal relaxation time limits damage.

Laser classes: Class 1 exempt, Class 2 low-risk, Class 3R/3B moderate-risk, Class 4 high-power; Class 4 requires controlled area, eye protection, and trained personnel.

Ablative lasers (CO2, erbium:YAG) remove epidermis and heat dermis; non-ablative lasers (Nd:YAG, diode) preserve epidermis; fractional devices create microthermal zones.

Intense pulsed light (IPL) is polychromatic, not a laser; used for hair removal, pigment, and vascular lesions; requires careful parameter selection.

Fitzpatrick skin types IV–VI have higher melanin, increasing risk of burns and PIH with laser and IPL; use longer wavelengths and conservative settings.

Eye protection: wavelength-specific goggles for client and operator; never look directly into beam; use non-reflective surfaces.

Contraindications: photosensitizing medications (isotretinoin, tetracycline), pregnancy, active infection, recent sun exposure or tanning, history of keloids.

Post-laser care: cooling, gentle cleansing, moisturizer, strict sun avoidance and SPF; avoid picking crusts; report blistering or prolonged erythema.

Primary lesions: macule (flat, color change), papule (raised, <1 cm), nodule (raised, >1 cm), vesicle (fluid-filled, <1 cm), bulla (>1 cm), pustule (pus-filled), wheal (edema).

Secondary lesions: scale, crust, erosion, ulcer, fissure, scar, lichenification; these evolve from primary lesions.

ABCDE melanoma warning: Asymmetry, Border irregularity, Color variation, Diameter >6 mm, Evolving changes; refer immediately.

Basal cell carcinoma: pearly papule with telangiectasia, rolled border, central ulceration; squamous cell carcinoma: scaly, crusted, may bleed.

Contagious conditions: impetigo, ringworm, scabies, herpes simplex, warts; do not treat; refer to physician.

Skin types: normal, dry, oily, combination, sensitive; skin conditions: acne, rosacea, hyperpigmentation, aging; distinguish type from condition.

Wood’s lamp: UV light reveals fluorescence; blue-white = normal, yellow = sebum, coral-red = porphyrins (acne), brown = melanin, white = depigmentation.

Allergic contact dermatitis: delayed hypersensitivity; patch testing by physician; avoid known allergens such as fragrances, preservatives, nickel.

Referral criteria: suspected malignancy, severe inflammation, infection, unexplained lesions, no improvement after conservative care.

Chain of infection: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host; break any link to prevent infection.

Standard precautions: hand hygiene, gloves, eye protection, gown when splashing likely; treat all blood and body fluids as infectious.

Disinfection levels: low-level (soap and water, some wipes), intermediate (70% isopropyl alcohol, quaternary ammonium), high-level (glutaraldehyde, hydrogen peroxide); sterilization kills all microorganisms including spores.

Hand washing: at least 20 seconds with soap and water; alcohol-based sanitizer when hands not visibly soiled.

Single-use items: needles, blades, microdermabrasion crystals, wooden applicators; never reuse.

Bloodborne pathogens: HIV, hepatitis B and C; hepatitis B vaccine recommended for estheticians; report exposures immediately.

Sharps disposal: puncture-resistant, labeled container; never recap needles; follow local regulations.

Sanitation vs. disinfection vs. sterilization: sanitation reduces contaminants; disinfection kills most pathogens; sterilization kills all including spores.

Safety: patch test products, keep MSDS/SDS accessible, label all containers, maintain electrical safety, and follow manufacturer’s instructions.

Skin layers: epidermis (stratum corneum, granulosum, spinosum, basale), dermis (papillary and reticular), subcutaneous (hypodermis).

Epidermal turnover: approximately 28 days; slows with age; retinoids and AHAs accelerate turnover.

Dermis contains collagen (strength), elastin (elasticity), glycosaminoglycans (hydration), fibroblasts, blood vessels, nerves, and appendages.

Melanocytes produce melanin via tyrosinase; melanin transfers to keratinocytes via melanosomes; protects from UV.

Sebaceous glands secrete sebum, controlled by androgens; overactivity contributes to acne.

Vasculature: arterioles, capillaries, venules; vasodilation causes erythema; vasoconstriction reduces redness.

Lymphatic system drains excess fluid and waste; massage direction follows lymph flow toward nodes.

Nerve endings: Meissner’s corpuscles (touch), Pacinian corpuscles (pressure), free nerve endings (pain, temperature).

Aging: collagen and elastin decline, hydration decreases, cell turnover slows, subcutaneous fat diminishes.

pH scale 0–14; skin surface pH ~4.7–5.5; acids lower pH, bases raise; AHAs require low pH (3–4) to exfoliate effectively.

Emulsion types: oil-in-water (O/W) lighter, water-in-oil (W/O) heavier; emulsifiers stabilize mixtures of oil and water.

Surfactants: cleanse by lowering surface tension; amphoteric (gentle), anionic (foaming), nonionic (mild), cationic (conditioning).

Humectants (glycerin, hyaluronic acid, sorbitol) attract water; emollients (oils, esters) soften; occlusives (petrolatum, dimethicone) prevent water loss.

Antioxidants: vitamin C (L-ascorbic acid), vitamin E, ferulic acid; stabilize formulations and neutralize free radicals.

Preservatives: parabens, phenoxyethanol, benzyl alcohol; prevent microbial growth; required in water-containing products.

Active ingredients: retinoids (vitamin A), niacinamide (B3), peptides, hydroxy acids; concentration and vehicle affect efficacy.

Sunscreens: organic (chemical) absorb UV, inorganic (physical) reflect/scatter; SPF measures UVB protection; broad-spectrum covers UVA and UVB.

Ingredient labeling: listed in descending order of concentration; below 1% may be listed in any order; “fragrance” can hide allergens.

Scope of practice: estheticians treat the epidermis and provide cosmetic services; diagnose and treat disease only by licensed medical professionals.

Licensure: state board requirements include approved training hours, examination, and continuing education; verify current license.

Client records: informed consent, health history, treatment notes, patch test results; retain per state law; maintain confidentiality (HIPAA where applicable).

Informed consent: explain benefits, risks, alternatives, and aftercare; document client questions and answers.

Professional liability insurance: covers malpractice claims; verify coverage for advanced treatments.

Business structures: sole proprietorship, partnership, LLC, corporation; each has tax and liability implications.

Pricing: calculate cost of goods, labor, overhead, and profit margin; retail markup typically 2–2.5 times wholesale.

Marketing ethics: no false claims, no guaranteed results, before/after photos with consent, comply with advertising regulations.

OSHA: Hazard Communication Standard requires SDS for chemicals; bloodborne pathogens standard applies where exposure risk exists.