Dermatologic Surgery, Lasers and Cosmetic Dermatology
Surgical principles
Know elliptical excision design, margin guidelines (BCC 3-4 mm, SCC 4-6 mm, melanoma per Breslow), and closure techniques (primary, secondary, flaps, grafts). Mohs micrographic surgery is indicated for high-risk BCC/SCC, recurrent tumors, and cosmetically sensitive sites.
Complications
Hematoma, infection, dehiscence, hypertrophic scar, and keloid. Keloids extend beyond the original wound; hypertrophic scars stay within it.
Lasers and energy devices
Vascular lasers (pulsed dye, 585/595 nm) target hemoglobin; pigment lasers (Q-switched, picosecond) target melanin; fractional ablative (CO2, erbium) resurface; hair removal uses 755/810/1064 nm. Understand selective photothermolysis: wavelength, pulse duration, and fluence.
Cosmetic
Botulinum toxin (neuromodulator), fillers (hyaluronic acid, calcium hydroxylapatite), chemical peels (superficial, medium, deep), and sclerotherapy. Know contraindications and complication management (vascular occlusion with fillers).
Traps
- Using ablative lasers on darker skin without caution; postinflammatory hyperpigmentation risk.
- Confusing keloid and hypertrophic scar management (steroids, excision, radiotherapy).
- Ignoring margin guidelines in melanoma.
Rule of thumb
Select laser by chromophore: hemoglobin (vascular), melanin (pigment/hair), water (ablative resurfacing).
Worked example
A patient with a recurrent BCC on the nasal ala: choose Mohs surgery for tissue conservation and margin control.