CLT Vascular & Pigmented Lesion Treatment 3 — Questions and Answers
Question 1: Which laser system is FDA-cleared and most commonly used for treating spider veins (leg telangiectasias) on fair-skinned patients?
- CO2 laser at 10,600 nm
- Nd:YAG laser at 1064 nm (Correct answer)
- Excimer laser at 308 nm
- Diode laser at 810 nm with high fluence
Correct answer: Nd:YAG laser at 1064 nm
The long-pulsed Nd:YAG at 1064 nm penetrates deeply enough to reach leg telangiectasias and is effective on fair skin with lower epidermal melanin absorption.
Question 2: Post-inflammatory hyperpigmentation (PIH) after pigmented lesion treatment is best prevented by:
- Increasing fluence to complete treatment in fewer sessions
- Pre-treating with topical hydroquinone and sun avoidance (Correct answer)
- Using epidermal cooling only after the procedure
- Skipping test spots and proceeding directly to full treatment
Correct answer: Pre-treating with topical hydroquinone and sun avoidance
Pre-treatment with hydroquinone to suppress melanocyte activity and strict sun avoidance before and after treatment significantly reduces PIH risk.
Question 3: The principle of selective photothermolysis requires that pulse duration be:
- Longer than the thermal relaxation time of the target
- Equal to or shorter than the thermal relaxation time of the target (Correct answer)
- Independent of the target's thermal relaxation time
- At least 10 times the thermal relaxation time
Correct answer: Equal to or shorter than the thermal relaxation time of the target
For selective photothermolysis, pulse duration must be less than or equal to the TRT of the target to confine thermal damage to the intended chromophore.
Question 4: Which condition is an absolute contraindication to laser treatment of vascular lesions?
- History of mild sunburn
- Active cutaneous infection or open wound at the treatment site (Correct answer)
- Patient age over 60
- Previous treatment with topical retinoids
Correct answer: Active cutaneous infection or open wound at the treatment site
Active infection or open wounds at or near the treatment site are absolute contraindications due to risk of spreading infection and compromised healing.
Question 5: A patient develops milia 4 weeks after laser treatment of a vascular birthmark. The most likely cause is:
- Allergic reaction to topical anesthetic
- Occlusion of hair follicles during wound healing (Correct answer)
- Laser-induced hyperpigmentation
- Over-aggressive cooling that froze the skin
Correct answer: Occlusion of hair follicles during wound healing
Milia form when keratin becomes trapped in occluded follicular infundibula during post-laser re-epithelialization and wound healing.
Question 6: When treating a nevus of Ota, which laser modality provides the most effective removal with lowest risk of scarring?
- Long-pulsed alexandrite
- Q-switched Nd:YAG at 1064 nm (Correct answer)
- Pulsed dye laser at 595 nm
- Fractional CO2 laser
Correct answer: Q-switched Nd:YAG at 1064 nm
The Q-switched Nd:YAG at 1064 nm is the gold standard for nevus of Ota because it targets deep dermal melanocytes with nanosecond pulses that minimize thermal damage.
Question 7: Dynamic cooling devices (DCD) used with pulsed dye laser primarily protect which skin structure?
- Dermal collagen
- Subcutaneous fat
- The epidermis (Correct answer)
- Sebaceous glands
Correct answer: The epidermis
DCD sprays a cryogen burst milliseconds before the laser pulse, cooling the epidermis to prevent surface damage while allowing energy to reach the target vessel.
CLT Vascular & Pigmented Lesion Treatment 3
Which laser system is FDA-cleared and most commonly used for treating spider veins (leg telangiectasias) on fair-skinned patients?