61 Lasers, Skin Resurfacing, & Alopecia

Question 1

Describe age-related changes of the skin.

Answer 1

Describe age-related changes of the skin.

The skin changes in the aging process include: thinning of the dermis and epidermis, effacement of the epidermal-dermal junction (most consistent change), thinning of the subcutaneous fat, and loss of organization of elastic fibers and collagen. These changes contribute to increased skin laxity and wrinkling characteristics of the aged face.

Question 2

Describe the Fitzpatrick skin type classification system.

Answer 2

Describe the Fitzpatrick skin type classification system.

The Fitzpatrick skin type classifies the degrees of skin pigmentation and ability to tan. It is graded from I to VI and forecasts sun sensitivity, susceptibility to photodamage, and ability for melanogenesis. It also provides important information related to risk factors for complications during skin resurfacing procedures. Types III through VI have a higher risk for pigmentary dyschromia (hypo- or hyperpigmentation) after skin resurfacing procedures.

Question 3

What are the different methods of skin resurfacing and how do they promote rejuvenation?

Answer 3

What are the different methods of skin resurfacing and how do they promote rejuvenation?

The different methods are chemical peels, dermabrasion, and laser photothermolysis. Superficial resurfacing (microdermabrasion and superficial chemical peels) exfoliate the epidermis only and stimulate regeneration and thickening of the epidermis. Medium and deep resurfacing (medium and deep chemical peels, dermabrasion, and lasers) penetrate into the superficial and deep dermis, inducing the production of collagen.

Question 4

What are the main indications for chemical peels and dermabrasion?

Answer 4

What are the main indications for chemical peels and dermabrasion?

Photodamage, fine wrinkles, pigmentary dyschromia, and acne scars.

Question 5

What are the agents used for superficial chemical peels?

Answer 5

What are the agents used for superficial chemical peels?

Superficial chemical peels (epidermis) can be done with: trichloroacetic acid (TCA) 10% to 30% solution, Jessner’s solution (resorcinol, salicylic acid, lactic acid, and ethanol), glycolic acid 40% to 70% solution, and salicylic acid 5% to 15% solution.

Question 6

What are the agents used for medium-depth chemical peels?

Answer 6

What are the agents used for medium-depth chemical peels?

The medium-depth peel (papillary dermis) agents are: trichloroacetic acid (TCA) 35% to 40% solution, the combination of 35% TCA with other agents (35% TCA + solid CO2, 35% TCA + Jessner’s solution, 35% TCA + 70% glycolic acid), and phenol 88% solution.

Question 7

What are the agents used for deep chemical peels?

Answer 7

What are the agents used for deep chemical peels?

The deep chemical peel (reticular dermis) agents are: trichloroacetic acid (TCA) 50% and the Baker-Gordon phenol peel (phenol 88%, croton oil, septisol, and distilled water). The addition of croton oil, an epidermolytic agent, increases the penetration of phenol into the dermis.

Question 8

What are the limitations associated with the use of phenol?

Answer 8

What are the limitations associated with the use of phenol?

The use of phenol is associated with cardiotoxicity (mostly premature ventricular contractions), hepatotoxicity, and nephrotoxicity. Phenol application requires intravenous hydration and cardiac monitoring for the development of arrhythmias. The facial subunits should be treated in 15-minute intervals to avoid toxicity.

Question 9

Describe the complications related to chemical peels.

Answer 9

Describe the complications related to chemical peels.

The complications associated with chemical peel resurfacing include milia formation (most common complication with all resurfacing procedures), hyper- or hypopigmentation, scar formation, allergic or irritant dermatitis, bacterial or fungal (most commonly Candida) infection, and reactivation of herpes simplex virus (which could lead to scarring).

Question 10

What is dermabrasion?

Answer 10

What is dermabrasion?

Dermabrasion is a method for skin resurfacing that uses a mechanical injury to the skin. It is usually performed using an abrasive wheel that is attached to a drill motor and a hand-piece.

Question 11

What is a laser?

Answer 11

What is a laser?

Laser stands for Light Amplification by Stimulated Emission of Radiation. It’s a light that is collimated (parallel), coherent (same frequency and periodicity), and monochromatic (single wavelength).

Question 12

What is selective photodermolysis?

Answer 12

What is selective photodermolysis?

Selective photothermolysis is the property of maximal absorbance of the laser by the targeted tissue cromophore with minimal damage of surrounding tissues.

Question 13

What is ablative laser resurfacing?

Answer 13

What is ablative laser resurfacing?

Ablative laser resurfacing involves the principle of selective photothermolysis with the target tissue (cromophore) being water. The most common lasers used for ablation are CO2 and Erbium-YAG.

Question 14

What is the difference between CO2 and Erbium-YAG lasers?

Answer 14

What is the difference between CO2 and Erbium-YAG lasers?

Er-YAG energy is absorbed more efficiently the skin (tenfold greater absorption) than is energy from the CO2 laser. This leads to a more precise tissue ablation with less adjacent thermal injury. This, in turn, leads to a shorter recovery time, less erythema, and a lower risk of hypo- or hyperpigmentation. On the other hand, it produces less tissue tightening.

Question 15

What is nonablative and fractional laser resurfacing?

Answer 15

What is nonablative and fractional laser resurfacing?

Nonablative resurfacing produces dermal thermal injury to improve rhytids and photodamage while preserving the epidermis. Fractional resurfacing thermally ablates microscopic columns of epidermal and dermal tissue in regularly spaced arrays over a fraction of the skin surface.

Question 16

How do nonablative lasers produce photorejuvenation?

Answer 16

How do nonablative lasers produce photorejuvenation?

They work by the induction of proliferation of fibroblasts with new collagen (types I and III) and elastin deposition in the papillary dermis. Infrared and visible light lasers are used with cooling mechanisms to protect the overlying epidermis.

Question 17

Is there a need for any preoperative treatment?

Answer 17

Is there a need for any preoperative treatment?

Yes. All patients undergoing laser resurfacing should take antiviral prophylaxis and avoid sun exposure prior to resurfacing. The use of hydroquinone, isotretinoin, glycolic acid, and antibiotics is less established.

Question 18

What are important considerations in patient selection for laser resurfacing?

Answer 18

What are important considerations in patient selection for laser resurfacing?

One of the most important considerations is the patient’s skin type. The safest skin types are Fitzpatrick I and II. Types III through VI are more susceptible to complications.

Question 19

What are the most common complications associated with laser skin resurfacing?

Answer 19

What are the most common complications associated with laser skin resurfacing?

Milia, hypopigmentation, hyperpigmentation, scar formation, infection (viral, fungal and bacterial), and contact dermatitis.

Question 20

What are follicular units?

Answer 20

What are follicular units?

Hair follicles grow together in groups, the follicular unit (FU). This unit, which is considered the fundamental component of hair transplantation, consists of one to four terminal hair follicles with its associated sebaceous gland, arrector pili muscle, blood supply, and neural plexus surrounded by a fine adventitial collagen sheath. The FU is considered not only an anatomic unit but also a physiologic one.

Question 21

Describe the hair cycle.

Answer 21

Describe the hair cycle.

Hair growth is a cyclical phenomenon with a period of growth (anagen), involution (catagen), and rest (telogen). In the normal scalp, 90 to 95% of the hairs are in anagen, about 1% in catagen, and 5% to 10% in the telogen phase. Each hair goes through this process 10 to 20 times during a lifetime. This cycle is regulated by a complex signaling system, which is not yet fully understood.

Question 22

What is androgenic alopecia?

Answer 22

What is androgenic alopecia?

Androgenic alopecia (AGA) affects males and females. Its onset is extremely variable and seems to be determined by the presence of circulating androgens. The prevalence of AGA is extremely variable, affecting about 30% of males at 30 years of age and about 50% of the 50-year-old males. This type of alopecia is nonscarring and has a characteristic pattern with variation in hair shaft diameter and the presence of miniaturized hair leading to their transformation into vellus-like follicles. The exact mechanism by which the androgens cause hair loss remains unclear. It is likely that, in susceptible follicles in the scalp, dihydrotestosterone (DHT) binds to the androgen receptor and the hormone-receptor complex activates genes that gradually transform large terminal hairs into miniaturized hairs.

Question 23

How is androgenic alopecia is classified?

Answer 23

How is androgenic alopecia is classified?

Androgenic hair loss in males, or male pattern baldness (MPB), often follows a characteristic pattern beginning with temporal recession followed by diffuse thinning of the crown area, eventually leading to complete hair loss in this region. Balding in this area enlarges and eventually meets the temporal recession. On the final stages of progression the parietal and occipital fringes thin and recede. This step-wise progression was classified by Norwood, with a grading scale ranging from I to VII (see below).

Question 24

Describe female pattern baldness.

Answer 24

Describe female pattern baldness.

Because the role of androgens on alopecia in women remains uncertain, female pattern hair loss (FPHL) became the preferred term for AGA in women. It affects about 20% of all women, with the onset being as early as the third decade with a steady progression until acceleration during menopause. Diagnosis of FPHL is clinical, based on the characteristic appearance of the scalp. It normally does not require further workup, but patients should be asked about signs of hirsutism, acne, menstrual and hormonal abnormalities. The most widely used classification system for FPHL was proposed by Ludwig (see below). The frontal hairline usually remains intact and the hair loss occurs on the top of the scalp and is arbitrarily divided into three degrees of severity.

Question 25

What are the nonsurgical treatment options for alopecia?

Answer 25

What are the nonsurgical treatment options for alopecia?

Without treatment, AGA advances at a rate of about 5% a year. There are currently two drugs available foe treatment of AGA, Minoxidil and Finasteride. Minoxidil is a vasodilator and its mechanism of action to promote hair growth is not well understood, but seems to be independent of vasodilation. It causes an initial surge in hair growth, which quickly stops when the medication is stopped. Adverse effects include scalp irritation, dryness, itching, and redness. Finasteride is a competitive inhibitor of type 2 5α-reductase that inhibits the conversion of testosterone into DHT. It lowers the levels of DHT but has no affinity for other androgen receptors, therefore does not interfere with metabolic actions of testosterone. The adverse effects include decreased libido, erectile dysfunction, and ejaculatory dysfunction, which are reversible with discontinuation of the medication.

Question 26

Describe follicular unit transplantation.

Answer 26

Describe follicular unit transplantation.

Follicular unit transplantation (FUT) consists of the transfer of the individual FU, maximizing the amount of hair and minimizing the amount of scarring.

Its starts by dissecting the FUs and setting them apart into individual units of one, two, three, or four hairs. They are then transferred to the recipient site and inserted in small openings, which minimizes recipient site scarring and trauma to the local blood vessels, but more importantly, creates a snug fit for the FU. The main advantage of FUT, and one of the reasons for its popularity, is the remarkably natural appearance that it provides the patient.

Question 27

How are the FUs obtained?

Answer 27

How are the FUs obtained?

The FUs can be obtained through a single strip harvest or through follicular unit extraction (FUE). The strip technique starts by determining and marking the donor area on the occipital scalp. With a scalpel, the incision is made, beveling the knife along the axis of the follicles to avoid transection. The FUs are then dissected from the scalp strip, and the donor area is closed with sutures. In the FUE technique, a sharp 1-mm punch is used to incise into the midreticular dermis, stopping just above the subcutaneous tissue. This is done observing the angle of the hair shaft in the scalp and using the punch on the same axis to avoid transection. Then using a forceps or a suction-assisted device, the top of the graft is firmly grasped and pulled out.

Question 28

What is postsurgical effluvium?

Answer 28

What is postsurgical effluvium?

Postsurgical effluvium is the loss of preexisting hair in the FU following transplant and occurs to a small degree in some patients. This loss happens at any point from the first 3 weeks to 3 months after surgery and is usually minor and unnoticed by the patient. Significant postsurgical effluvium happens when a large number of transplanted grafts are placed in an area that contains a large proportion of miniaturized hairs. The degree of effluvium is unpredictable and can affect any patient, although it occurs more frequently in women. The patient needs to be reassured that hair will start growing again in the following 3 to 6 months.