Laser Hair Removal Techniques Flashcards

Which hair growth cycle phase is characterized by active cell division in the hair matrix and strong melanin production in the hair shaft?

Answer: Anagen (growth phase)

During anagen, the hair matrix cells divide rapidly and produce a fully pigmented shaft that is structurally connected to the dermal papilla. The high melanin content and direct connection to the bulb make anagen follicles the most sensitive to laser-induced thermal destruction.

A patient with Fitzpatrick type III skin requests laser hair removal on the legs. Which parameter combination is most appropriate to balance efficacy and safety?

Answer: 755 nm Alexandrite, 12–18 ms pulse duration, integrated contact cooling

For Fitzpatrick type III, the 755 nm Alexandrite laser provides good melanin absorption for efficacy. A pulse duration of 12–18 ms is within the TRT of the follicle, allowing selective heating. Integrated contact cooling protects the epidermis. Short pulses at 694 nm Ruby carry higher epidermal burn risk for type III skin.

What is the recommended pre-treatment instruction regarding shaving and waxing before a laser hair removal session?

Answer: Shave 24–48 hours before treatment; avoid waxing, plucking, or threading for 4–6 weeks prior

Shaving 24–48 hours before treatment removes the surface hair shaft (which could carbonize and scatter laser energy) while leaving the follicle intact. Waxing, plucking, or threading removes the hair shaft and papilla from the follicle, eliminating the chromophore target; these must be avoided for 4–6 weeks before treatment.

What is the minimum recommended Sun Protection Factor (SPF) for post-laser hair removal sun protection, and for how long should it be applied?

Answer: SPF 30 or higher for at least 4–6 weeks post-treatment and throughout the treatment course

Post-laser skin is more photosensitive and at risk of post-inflammatory hyperpigmentation (PIH) with UV exposure. Broad-spectrum SPF 30+ sunscreen should be applied consistently for at least 4–6 weeks post-treatment and throughout the full treatment course to reduce PIH risk, particularly in skin types III and above.

Which of the following best describes 'fluence' as used in laser hair removal protocols?

Answer: The energy delivered per unit area, expressed in joules per square centimeter (J/cm²)

Fluence (radiant exposure) is the laser energy delivered per unit area, expressed in J/cm². It is the primary dosimetric parameter in laser hair removal protocols. Adequate fluence ensures sufficient heat generation in the follicle; excessive fluence risks epidermal injury. Fluence = Power (W) × Pulse Duration (s) ÷ Spot Area (cm²).

A patient receiving axillary laser hair removal develops blistering immediately after treatment. What is the correct immediate management?

Answer: Stop treatment, cool the area with cool water or gel, do not rupture blisters, document, and follow wound care protocol

Blistering indicates an epidermal burn (excessive thermal injury). Treatment must be stopped immediately. Cool the area to arrest heat conduction. Intact blisters should not be punctured, as they provide a sterile wound covering. The event must be documented, the patient counseled on wound care, and parameters reviewed to prevent recurrence.