Laser Treatment Flashcards
A 42-year-old woman is scheduled to undergo facial resurfacing with a fractionated carbon dioxide laser. This procedure acts by targeting which of the following substances in skin? A) Collagen B) Elastin C) Hyaluronic acid D) Melanin E) Water
E) Water
Water and skin resurfacing
The principle of selective photothermolysis as applied to skin resurfacing (ablation) is based upon water content. The epidermis is composed of 90% water and is vaporized at temperatures in excess of 212°F (100°C). The carbon dioxide laser has water as its chromophore. The carbon dioxide laser has a wavelength of 10,600 nm and has a water absorption coefficient of 800/cm.
A 45-year-old woman comes to the office because of a rash and a burning sensation on her face 1 week after undergoing carbon dioxide cutaneous laser resurfacing. Physical examination shows erythematous pustules on the right side of the face in the V3 distribution. Which of the following agents is the most appropriate treatment? A ) Oral acyclovir B ) Oral cephalexin C ) Oral prednisone D ) Topical bacitracin E ) Topical petrolatum
A ) Oral acyclovir
Most common infectious complication associated with skin resurfacing
The most frequent infectious complication associated with resurfacing is a reactivation of the herpes simplex virus (HSV). It is suspected that direct laser trauma to the skin leads to latent viral activation and shedding.
Percent of patients undergoing laser resurfacing with HSV outbreak and prophylaxis indications
Herpetic outbreaks are experienced by roughly 2 to 7% of all laser-treated patients despite antiviral prophylaxis. In addition, due to the high incidence of latent HSV infection, any patient (regardless of prior HSV history) planning to undergo full-face or perioral resurfacing should be given oral antiviral prophylaxis in an effort to reduce viral reactivation, which could subsequently lead to scarring.
Early detection of post laser HSV
Early postlaser detection of HSV is often difficult because there is no intact epithelium, and, rather than the characteristic grouped vesicles or pustules, infection is manifested by small, superficial erosions. Symptoms of HSV reactivation include tingling, burning, or discharge from isolated foci within the treated areas.
Extensive postlaser eruptions of HSV: complications
Extensive eruptions can result in disseminated infection and atrophic scarring, and therefore, must be recognized early and treated aggressively
Treatment of peri-laser resurfacing HSV outbreak
Oral antiviral agents, such as acyclovir, famciclovir, or valacyclovir, are routinely administered 1 to 2 days before the laser resurfacing procedure and are continued for another 7 to 10 days until reepithelialization is complete. If a herpetic outbreak occurs despite prophylaxis, patients should either be switched to a different antiviral agent or have their dosage increased to maximal herpes zoster doses (acyclovir 800 mg 5 times daily or famciclovir or valacyclovir 500 mg 3 times daily).
A 45-year-old woman is being evaluated because of discrete, red, facial capillaries that she would like to have removed. Which of the following lasers is most appropriate to ablate the vessels? A ) KTP (532-595 nm) B ) Q-switched ruby (694 nm) C ) Nd:YAG (1064 nm) D ) Er:YAG (2940 nm) E ) Carbon dioxide (10,600 nm)
A ) KTP (532-595 nm)
The 532-595 nm wavelength is the most appropriate choice, as it has the highest affinity for the vessels and can be more effective with the appropriate settings.
1064-nm laser application
The 1064-nm laser can be used for hair reduction or collagen stimulation but works on the deeper layers and is more specific for darker pigmentation of vessels, such as blue. It can be used for vessel reduction in the leg; however, facial vessels are more superficial and often more red than blue in coloration.
A 50-year-old woman comes to the office because she developed a vesicular rash five days after undergoing full face carbon dioxide laser resurfacing to treat sun-damaged skin and acne scars. Which of the following is the most appropriate initial step in management?
A ) Administration of an antibiotic
B ) Administration of an antimicrobial scrub
C ) Administration of an antiviral agent
D ) Administration of a corticosteroid
E ) Observation
C ) Administration of an antiviral agent
HSV incubation period from time of skin resurfacing procedure
HSV infection has a three-to five-day incubation period from the time of the procedure to the onset of clinical infection.
A 59-year-old woman comes to the office because she is unhappy with the long-term results of carbon dioxide laser resurfacing performed three years earlier to treat rhytides on the upperlip. Which of the following is the most likely complication that is causing her dissatisfaction? A ) Hyperpigmentation B ) Hypertrophic scarring C ) Hypopigmentation D ) Persistent erythema E ) Telangiectasia
C ) Hypopigmentation
The success of carbon dioxide laser skin resurfacing is generally attributed to:
The success of carbon dioxide laser skin resurfacing is generally attributed to long-termne collagenesis and neoelastogenesis
Main drawback of carbon dioxide laser resurfacing; other potential complications
The main drawback is a high rate of hypopigmentation, which is very distressing to patients.
Although persistent erythema and hyperpigmentation can be troublesome in the first year after treatment, neither is typically seen as long-term sequelae of the procedure. Hypertrophic scarring is a possible complication of treatment; however, it is not reported as a common long-term complication of the procedure in several large series of studies.
Effectiveness of carbon dioxide laser resurfacing on the upper lip
Carbon dioxide laser resurfacing is a highly effective treatment of rhytides of the upper lip that will last for a long time (more than six years) with low rates of recurrence.
(Red, purple, green, yellow, blue, black…CF)
A 35-year-old woman comes to the office for removal of the tattoo shown in the photograph. The tattoo was professionally applied. The patient undergoes five treatments with a Q-switched Nd:YAG (1064 nm) laser. After completion of laser therapy, areas of red pigment remain. Additional treatment with which of the following lasers is the most appropriate next step in management?
(A)Erbium: YAG (2940 nm)
(B)Q-switched alexandrite (755 nm)
(C)Q-switched Nd:YAG (532 nm)
(D)Q-switched ruby (694 nm)
(E)Ultrapulsed CO2 (10,600 nm
C)Q-switched Nd:YAG (532 nm)
Estimated percent of people who have considered tattoo removal
An estimated seven to 20 million people in the United States have at least one tattoo, and approximately 17% have considered tattoo removal.
Professional vs amateur tattoos
Compared with amateur tattoos, professional tattoos often contain various densely packed colored pigments at a uniform depth
Type of laser for tattoo removal
Quality-switched (Q-switched) lasers enable the deposit of energy very quickly, thus rupturing cells containing pigment and triggering phagocytosis and packaging of tattoo fragments for lymphatic drainage. Because different pigments respond to different wavelengths, it is rare that one laser system can be used alone to remove all combinations of inks.
Q-switched Nd:YAG 1064 nm and tattoos
The Q-switched Nd:YAG 1064 nm has the deepest penetration and carries the least risk of hypopigmentation but is least effective in removing brightly colored tattoos.
Q-switched Nd:YAG 532 nm and tattoos
The Nd:YAG 532 nm is effective for red, orange, and occasionally yellow ink. Because this wavelength is also absorbed by hemoglobin, purpura often occurs after treatment and can last for seven to 10 days
Q-switched alexandrite and ruby lasers vs tattoos
The Q-switched alexandrite and ruby lasers are effective for the treatment of black, blue, and green pigment; however, because their wavelengths are well absorbed by melanin, transient hypopigmentation and even permanent depigmentation can be a problem, particularly in patients with Fitzpatrick type V or VI skin types
An Er:YAG laser targets which of the following chromophores? (A)Blue dye (B)Collagen (C)Hemoglobin (D)Melanin (E)Water
(E)Water
Amount of heat generated by a laser is a function of:
Lasers generate heat in the target tissue that dissipates by conduction. The amount of heat generated is a function of the wavelength of the laserand the duration of exposure.
Selective tissue injury of a laser is caused by:
Selective tissue injury is caused by the choice of a wavelength of energy that is specific for a particular target chromophore within the skin.
Er:YAG laser
The Er:YAG laser is an ablative laser with a wavelength of 2940 nm and a targetchromophore of water. There is less thermal diffusion to the surrounding tissues with an Er:YAG laser than with a CO2 laser, although both have the same target chromophore
Nd:YAG laser
The Nd:YAG laser affects blood vessels, red blood cells, collagen, and melanin.
Fractional photothermolysis
Fractional photothermolysis uses a blue dye template, which also serves as the target chromophore, and divides the skin into microscopic thermal zones.
A 42-year-old woman comes to the office for consultation regarding improvement of the appearance of her facial skin. Resurfacing with a carbon dioxide laser is contraindicated in this patient if she has been treated recently with which of the following drugs? (A)Acyclovir (B)Glycolic acid (C)Hydroquinone (D)Isotretinoin (E)Tretinoin
(D)Isotretinoin
Isotretinoin and skin resurfacing procedures
Isotretinoin (Accutane) is contraindicated in any skin resurfacing procedures. Although its use for the treatment of acne is regulated, because of its significant risk for causing birth defects, it may also interfere with healing after resurfacing procedures. This complication may occur even if themedication has not been used for one year.
Duration between isotretinoin treatment and skin resurfacing procedure
Isotretinoin use should be discontinued for at least one year - 18 months before skin resurfacing procedures
A 37-year-old woman who underwent full-face resurfacing with a carbon dioxide laser seven days ago comes to the office because she has chills, malaise, and painful lesions of the face. Temperature is 38.7EC (101.7EF). Physical examination shows ulcerated, diffusely distributed lesions over the face. A four-day regimen of acyclovir 400 mg three times daily has not alleviated the patient’s symptoms. Results of Tzanck smear and viral culture are pending. Which of the following therapies is the most appropriate next step in management?
(A)Intravenous acyclovir and ciprofloxacin
(B)Oral acyclovir at a higher dose
(C)Oral acyclovir at a more frequent dose
(D)Oral valacyclovir
(E)Oral valacyclovir and ciprofloxacin
(A)Intravenous acyclovir and ciprofloxacin
Herpes simplex is difficult to recognize on resurfaced skin. Moreover, primary or secondary bacterial infection cannot be overlooked. Therefore, antibiotic coverage is prudent, particularly until culture results are available.
This patient presented with signs and symptoms of systemic herpetic infection, which may include disseminated cutaneous lesions, shortness of breath, high fever and chills, malaise, headache, and neurologic changes. When these are present, hospital-based treatment with intravenous antiviral and antibiotic therapy is warranted.
Workup when a patient experiences an outbreak of herpes simplex despite use of antiviral prophylaxis
When a patient experiences an outbreak of herpes simplex despite the use of antiviral prophylaxis, the physician should perform a Tzanck smear and send viral, fungal, and bacterial cultures. The anti-herpetic dosage should be increased to zoster levels as well (acyclovir 800 mg five times a day, valacyclovir 500 mg three times a day.
Signs and symptoms of systemic herpetic infection
Signs and symptoms of systemic herpetic infection may include disseminated cutaneous lesions, shortness of breath, high fever and chills, malaise, headache, and neurologic changes. When these are present, hospital-based treatment with intravenous antiviral and antibiotic therapy is warranted.
A 28-year-old womanundergoes laser removal of a multicolored tattoo on the upper arm. The tattoo was professionally applied. Which of the following laser wavelengths is most appropriate to remove the yellow portions of this tattoo? (A) 532 nm (B) 698 nm (C) 755 nm (D) 1064nm (E) 1320 nm
(A) 532 nm
Orange and yellow tattoo inks are targeted by _____ range lasers
Orange and yellow tattoo inks are targeted specifically by lasers in the low (500-nm) range, making the 532-nm Q-switched Nd:YAG laser or the 510-nm pulsed-dye laser optimal for treatment.
First laser system developed solely for non ablative skin remodeling
Nd:YAG, long-pulsed 1320-nm laser treatment was the first system developed solely for nonablative skin remodeling.
Black tattoo inks may be targeted by _____ range lasers
The Q-switched Nd:YAG (1064-nm) laser is optimal for black pigment.
