Hyperpigmentation: An Overview of the Common Afflictions

Kimberly A. Cayce; Amy J. McMichael; Steven R. Feldman

Disclosures

Dermatology Nursing. 2004;16(5) 

In This Article

Lentigines Therapy

As with the management of melasma, numerous options for treating solar lentigines are available. Prevention is one of the most important interventions. This should be initiated during early childhood, continue throughout life and include sun avoidance, protective clothing, sunscreens, and sun-blocking agents. Once the lentigines have already developed, the goal of therapy is to lighten the hyperpigmented areas without adversely affecting the surrounding or underlying skin.

Typically, the same topical agents that exist for melasma therapy are used in the management of solar lentigines. The most commonly applied topicals include the retinoids, phenolic compounds, and alpha-hydroxy acids. Other agents such as topical hormonal creams may be useful. In one study, Premarin® cream, a topical conjugated estrogen, improved the appearance of photodamaged skin including the appearance of lentigines (Creidi et al., 1994). However, similar to the results in melasma, combination therapy maintains superiority over any single agent alone. One such example of successful combinations is that of mequinol (a phenolic compound) and tretinoin. The synergy of these two compounds was first established in a swine model and thought to be due to the presence of two different mechanisms of action on the inhibition of the pigmentary process (Nair, Parab, Suhr, & Tramposch, 1993) and later reproduced in human studies. This topical solution is the first combination therapy approved for treating solar lentigines. Fleischer, Schwartzel, Colby, and Altman (2000) found this compound to be more efficacious for solar lentigines than either agent alone. Local irritation, which is generally mild, is the most common side effect. To prevent a halo of surrounding hypopigmentation, this product should be applied to an area slightly smaller than the lentigo because the drug is drawn a few millimeters into the adjacent skin. Patients should begin with once daily application and increase to twice daily as tolerated, backing off if irritation develops.

Chemical peels illustrate positive outcomes in some patients. One clinical trial examining the effects of TCA peels noted success with 40% complete regression and 50% partial regression of the hyperpigmented spots (Cotellessa, Peris, Onorati, Fargnoli, & Chimenti, 1999). Following pretreatment with topical tretinoin and localized 20% TCA, a peel consisting of 50% salicylic acid, methyl salicylate, and croton oil proved efficacious in treating solar lentigines, even after one application (Swinehart, 1992). Benefits of tretinoin peels have also been observed in certain hyperpigmentation disorders, including that of photodamaged skin. In addition, a more rapid response occurs than that observed with topical retinoid creams (Cuce, Bertino, Scattone, & Birkenhauer, 2001).

For many decades, cryosurgery has been employed as a means to treat lentigines. Melanocytes are the skin cells most vulnerable to cold and destruct at temperatures of -4 to -7 degrees Centigrade. In contrast, squamous cells resist injury up to -20 degrees C (Hexsel et al., 2000). Because of this selective destruction, cryosurgery remains an effective therapy for lentigines. A study comparing cryosurgery to local dermabrasion for the treatment of solar lentigo on the back of the hands found comparable results between the two therapies, but less temporary side effects and a faster healing time were noted with dermabrasion (Hexsel et al., 2000). However, another clinical trial evaluating liquid nitrogen versus both argon and ICO2 lasers demonstrated superiority of the liquid nitrogen (Stern, Dover, Levin, & Arndt, 1994). Success of cryosurgery for PUVA-induced lentigines has also been reported (Leroy, Dompmartin, Dubreuil, & Louvet, 1996). Hypopigmentation following cryosurgery may occur and can be permanent. Minimizing this risk emerges with proper technique, in which one freezes the lesion intermittently for 7 to 10 seconds producing a one to two millimeter halo around the spot (Graham, Cerveny, Jr., & SanFilippo, 2003). Additional possible side effects include erythema, hyperpigmentation, atrophy, and pain.

Several different pigment-specific lasers have been used to treat solar lentigines. Included in the collection is the frequency-doubled Q-switched Nd:YAG, Q-switched ruby (QSRL), ICO2, and argon lasers. These lasers act by damaging the epidermis via thermal injury and therefore removing the pigmented lesions. To localize tissue destruction to the target lesions and minimize side effects such as textural changes or scarring, lasers such as the frequency-doubled Q-switched Nd:YAG and QSRL lasers are employed. They emit wavelengths that are absorbed more specifically by the targeted tissue and also use shorter pulse durations (specific photothermolysis) (Kilmer, Wheeland, Goldberg, & Anderson, 1994; Kopera, Hohenleutner, & Landthaler, 1996). In contrast to that of melasma, many of the lasers prove successful in managing solar lentigines, even after a single treatment. The frequency-doubled Q-switched Nd: YAG laser demonstrated better results after one treatment of face lentigines when compared to 35% trichloracetic acid (Li & Yang, 1999). Another study revealed that the Q-switched ruby laser removed lentigines more effectively and with less irritation than did glycolic acid peels (Kopera et al., 1996). Although decreased pigmentation of solar lentigines with ICO2 lasers has been shown (Dover, Smoller, Stern, Rosen, & Arndt, 1988), the effects are not as impressive as those with cryosurgery and more adverse events may ensue from the nonselective thermal damage. Because of the melanocyte-destructive nature of techniques such as cryosurgery (Gage, Meenaghan, Natiella, & Greene, Jr., 1979) and pigmented lesion dye lasers (Grekin, Shelton, Geisse, & Frieden, 1993), their adverse effects are more likely to be permanent. While not a laser, intense pulsed light, which also utilizes light wavelengths, appears promising as an effective means to treat lentigines with minimal side effects (Kawada et al., 2002; Moreno Arias & Ferrando, 2001).

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