CIDESCO Theory cheat sheet

The epidermis has five layers, deepest to surface: stratum basale, spinosum, granulosum, lucidum (palms and soles only), and corneum.

Epidermal turnover averages about 28 days in healthy adults and lengthens with age, slowing repair and desquamation.

Melanocytes in the stratum basale produce melanin, which determines skin colour and absorbs ultraviolet radiation.

The dermis contains collagen for tensile strength, elastin for elasticity, and glycosaminoglycans such as hyaluronic acid for hydration; it houses follicles, sebaceous glands and sweat glands.

Facial blood supply comes mainly from the facial artery (external carotid) with ophthalmic branches; venous drainage runs to the facial and ophthalmic veins.

Facial lymph nodes include submental, submandibular, preauricular and parotid groups; lymph drains toward these nodes, not away from them.

Facial bones include frontal, zygomatic, maxilla, mandible and nasal bones; the nasal septum is formed by the ethmoid and vomer.

Muscles of facial expression insert into skin and are supplied by the facial nerve (cranial nerve VII); the trigeminal nerve (V) carries facial sensation.

Lesion terminology: macule (flat colour change), papule (raised, under 1 cm), vesicle (fluid-filled), pustule (pus-filled), nodule (solid, deeper).

Skin type is classified as normal, dry, oily, combination or sensitive using four observations: pore size, sebum level, hydration and reactivity.

The Fitzpatrick scale (I–VI) predicts UV response: type I always burns and never tans, while type VI rarely burns.

Double cleansing uses an oil-based or emollient cleanser first to lift makeup and sebum, then a water-based cleanser; water should be lukewarm, not hot.

Alpha-hydroxy acids (glycolic, lactic) are water-soluble and act superficially; beta-hydroxy acid (salicylic) is oil-soluble and penetrates pores to target comedones.

Absolute contraindications to facial electrical treatments include pregnancy, epilepsy, pacemaker or metal implants, heart conditions and recent surgery.

Desincrustation uses the negative (alkaline) pole to saponify sebum before extraction; iontophoresis drives water-soluble product in by same-charge repulsion.

High-frequency current produces ozone and is used on acne; it is avoided over excessive hair growth, metal fillings and areas with broken skin.

Mask selection: clay/kaolin for oily skin, cream for dry or mature skin, gel for sensitive or congested skin, peel-off avoided on fine or vascular skin.

Facial massage sequence uses effleurage to open and close, with petrissage, tapotement, friction and vibration applied in the direction of lymphatic drainage.

Massage effects are mechanical (stretch and mobilise tissue), physiological (circulation, lymphatic flow, pain gating) and psychological (relaxation).

Absolute contraindications include DVT or thrombosis, fever, contagious skin disease, fracture, uncontrolled hypertension and recent surgery.

Effleurage is the opening and closing stroke and links all other movements; deep pressure follows venous and lymphatic flow toward the heart.

Petrissage covers kneading, picking up, wringing and rolling; it is applied to muscle bellies, never to joints or bony prominences.

Tapotement (hacking, cupping, clapping, beating) uses relaxed wrists for 30 seconds to 2 minutes and is avoided over the spine, kidneys and bone.

Lymphatic drainage uses light pressure of roughly 20–30 mmHg at a slow rhythm, directed toward the regional lymph nodes.

Carrier oils: sweet almond for general use, grapeseed for oily skin, jojoba for stability, coconut which is solid at room temperature.

Essential oils are typically diluted at 1–3% in a carrier oil; a patch test is performed 24–48 hours before first use.

Body wraps may be detoxifying, hydrating or thermal; they are contraindicated in claustrophobia, cardiovascular disease and pregnancy.

Sterilisation destroys all microorganisms including spores (autoclave: 121°C at 15 psi for 15–20 minutes); disinfection reduces pathogens but not spores.

Sanitising lowers bacteria on surfaces to a safe level; tools contacting skin or blood require hospital-grade disinfectant or sterilisation.

Standard precautions assume all blood and body fluids are infectious: hand hygiene, gloves, eye protection and no re-sheathing of needles.

The chain of infection has six links - infectious agent, reservoir, portal of exit, transmission, portal of entry and susceptible host; breaking any link prevents spread.

Waste segregation: sharps into a rigid yellow sharps container, blood-soaked items into clinical waste, never overfilled and never placed in general waste.

Fire extinguisher use follows PASS: Pull the pin, Aim at the base, Squeeze the handle, Sweep side to side; extinguisher classes are A solids, B liquids, C gases, E electrical.

COSHH requires assessment, control and recording of substances hazardous to health, with safety data sheets accessible in the salon.

Electrical safety requires PAT testing at the locally specified interval, RCD protection and immediate withdrawal of equipment with damaged cords.

All accidents are recorded in the accident book, and serious injuries or occupational illness are reported under the applicable local reporting regulation.

Gross profit = revenue − cost of goods sold; retail margin % = (retail price − cost) ÷ retail price × 100.

Break-even units = fixed costs ÷ (price per unit − variable cost per unit); break-even revenue = break-even units × price.

Service capacity = number of staff × available treatment hours × utilisation rate.

Par level = minimum stock + (average daily use × lead time); stock is rotated First In, First Out.

Key performance indicators include average client spend, rebooking rate, retention rate, retail attachment and staff utilisation.

Net pay = gross pay − statutory deductions (income tax, social insurance, pension contributions).

Recruitment separates the job description (duties and responsibilities) from the person specification (skills, qualifications, experience).

Data protection requires secure storage of client records, retention only as long as necessary, and client right of access to their data.

Client lifetime value = average spend × visits per year × years retained; marketing mixes use the 4 Ps of product, price, place and promotion.

Consultation sequence: greeting, medical history, skin or body analysis, contraindication screening, treatment plan, consent, then aftercare advice.

Informed consent must be voluntary, given by a competent client, and documented with the treatment, products and timings recorded.

Contraindications are absolute (must not treat), relative (treat with caution or modification), and may be local or general.

SOAP record format: Subjective (client's account), Objective (observations), Assessment (analysis), Plan (treatment and aftercare).

Active listening uses eye contact, open questions, paraphrasing and clarifying before responding; jargon is avoided.

Confidentiality: client information is shared only with consent or where legally required, and stored securely.

Professional boundaries require working only within competence and referring to a medical practitioner when in doubt.

Complaints procedure: listen, acknowledge, investigate, resolve and record, responding within the stated timescale.

Aftercare advice includes sun protection, avoiding heat and chlorine for 24–48 hours after waxing or peels, and hydration with suitable home care.