CLT Skin Anatomy & Treatment Selection 3 — Questions and Answers
Question 1: Which of the following best describes the concept of selective photothermolysis?
- Using low-power lasers to avoid thermal damage entirely
- Selecting a wavelength and pulse duration to heat a target chromophore while sparing surrounding tissue (Correct answer)
- Applying laser energy uniformly across the full skin surface
- Choosing lasers based solely on their visible color emission
Correct answer: Selecting a wavelength and pulse duration to heat a target chromophore while sparing surrounding tissue
Selective photothermolysis pairs a specific wavelength absorbed by the target chromophore with a pulse duration at or below the thermal relaxation time to confine damage.
Question 2: A client has telangiectasias on the nose. Which wavelength is most selectively absorbed by oxyhemoglobin for vascular targeting?
- 1064 nm
- 532 nm (Correct answer)
- 2940 nm
- 10,600 nm
Correct answer: 532 nm
The 532 nm wavelength (KTP laser) has a high absorption peak for oxyhemoglobin, making it ideal for superficial vascular lesions.
Question 3: What is the primary role of Merkel cells in the skin?
- UV protection via melanin transfer
- Slow-adapting mechanoreception for touch (Correct answer)
- Thermoregulation via sweat secretion
- Proliferation of new keratinocytes
Correct answer: Slow-adapting mechanoreception for touch
Merkel cells are specialized sensory cells in the epidermis that function as slowly adapting mechanoreceptors for fine touch discrimination.
Question 4: Skin thickness varies significantly across body regions. Which area typically has the thinnest skin, requiring reduced laser fluence?
- Back
- Palms
- Eyelids (Correct answer)
- Soles of feet
Correct answer: Eyelids
Eyelid skin is the thinnest on the body, requiring significantly reduced fluence to avoid burns and damage to the underlying ocular structures.
Question 5: During a laser skin resurfacing consultation, a patient mentions they took isotretinoin 8 months ago. What is the standard recommendation?
- Proceed with treatment at reduced settings
- Wait until 12–18 months after discontinuation (Correct answer)
- Treatment can proceed without restriction after 6 months
- Increase cooling to compensate for altered skin
Correct answer: Wait until 12–18 months after discontinuation
A waiting period of 12–18 months after isotretinoin discontinuation is recommended before ablative laser resurfacing due to impaired wound healing.
Question 6: The papillary dermis differs from the reticular dermis primarily in that it contains:
- Thicker collagen bundles and fewer blood vessels
- Fine loosely arranged collagen fibers and capillary loops (Correct answer)
- More adipose tissue and nerve trunks
- Dense elastic fibers and apocrine glands
Correct answer: Fine loosely arranged collagen fibers and capillary loops
The papillary dermis contains fine loosely organized collagen fibers and capillary loops that nourish the epidermis.
Question 7: Which condition would be a contraindication to laser hair removal in a patient with Fitzpatrick Type III skin?
- Mild dry skin
- Active herpes simplex infection in the treatment area (Correct answer)
- Light freckling
- Previous waxing 3 weeks prior
Correct answer: Active herpes simplex infection in the treatment area
Active herpes simplex infection is an absolute contraindication because laser treatment can trigger viral reactivation and spread.
CLT Skin Anatomy & Treatment Selection 3
Which of the following best describes the concept of selective photothermolysis?