Skin Care and Esthetics Fundamentals
What the domain tests
This domain covers the language of skin care: skin types versus conditions, barrier function, ingredient families, and consultation. The exam asks you to choose a safe, defensible treatment plan rather than a trendy one.
Core rules and concepts
- Skin type is genetically influenced (normal, dry, oily, combination, sensitive); a skin condition is changeable (dehydration, acne, hyperpigmentation, aging).
- The stratum corneum barrier depends on corneocytes, intercellular lipids, and natural moisturizing factor; a healthy surface pH is roughly 4.5–5.5.
- Humectants (glycerin, hyaluronic acid) attract water; emollients (squalane, shea butter) soften; occlusives (petrolatum) reduce water loss.
- Exfoliants differ: AHAs are water-soluble and surface-focused; BHA (salicylic acid) is oil-soluble and useful for oily, comedone-prone skin.
- The Fitzpatrick scale estimates UV response and guides sun-protection counseling, not skin grade.
Worked example
A client reports tightness after cleansing, flaking, and fine lines. She assumes she has dry skin and wants a strong scrub. Reasoning: tightness and flaking can signal dehydration (low water) even when oil is present. First restore the barrier with a gentle cleanser, a humectant, an emollient, and an occlusive at night; add broad-spectrum SPF. Defer aggressive exfoliation until irritation settles. Document the plan and recheck.
Traps that cost marks
Equating oily with hydrated; recommending retinoids without pregnancy or medication screening; over-exfoliating compromised skin; calling acne an infection or diagnosing disease; choosing products by fragrance rather than function.