Dec
2011
Vol. 30. No. 4
Role of Phototherapy in Patients with Skin of Color
Phototherapy has proven to be one of the most versatile and effective treatment options for
a variety of inflammatory and pigmentary skin diseases. However, the use of these treatment
modalities in patients of color requires some special considerations. The modality
chosen, the dosing of the treatment and duration of treatment are all issues to be considered
for patients of color treated with ultraviolet phototherapy. In addition, there are some
diseases which are more commonly seen in patients of color. These diseases may have
better treatment outcomes using newer phototherapeutic options such as the long pulsed
Nd:YAG laser or UVA1. As our population in the United States becomes more diverse it
would behoove all dermatologists to acquaint themselves with the special circumstances of
treating ethnic patients with phototherapy.
Semin Cutan Med Surg 30:184-189 © 2011 Elsevier Inc. All rights reserved.
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Dec
2011
Vol. 30. No. 4
Phototherapy in the Age of Biologics
Dermatologists are presented with a diversity of therapeutic modalities for the treatment of
inflammatory, sclerosing, and neoplastic conditions, but with the development of various new
irradiation devices that utilize specific parts of the electromagnetic spectrum, phototherapy has
become a more viable, accessible, and efficacious option in the treatment of these conditions.
The ultraviolet (UV) range (10-400 nm) is further subdivided into UVA and UVB, each of which
has been particularly useful in a number of skin conditions. The most commonly used forms of
UV irradiation are UVA1, psoralen plus UVA (PUVA), and narrowband (NB) UVB. Each of these
modalities differ in their mechanism of action, indications, and side effect profiles, and it is
important that clinicians be familiar with these differences. Today, phototherapy is a valuable
option in the treatment of many nonpsoriatic conditions including atopic dermatitis, sclerosing
skin conditions such as morphea, vitiligo, and mycosis fungoides. Due to its relative safety,
phototherapy may be used in most populations, including children and pregnant women.
However, contraindications and side effects are known and should be considered before
patients begin a phototherapeutic regimen.
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Dec
2011
Vol. 30. No. 4
Photodynamic Therapy: Current Evidence and Applications in Dermatology
Photodynamic therapy (PDT) involves the activation of a photosensitizing drug, which
preferentially localizes to diseased skin, by irradiation with light to cause selective cytotoxic
damage. Since its discovery in the early 20th century and the development of topical
photosensitizers 2 decades ago, PDT is increasingly being used in dermatology for a wide
range of neoplastic, inflammatory, and infectious cutaneous conditions. Topical 5-aminolevulinic
acid and methyl aminolevulinic acid, the most commonly used agents in PDT, have
received Food and Drug Administration approval for the treatment of actinic keratoses, and
many second-generation photosensitizers are under investigation. Compared with conventional
therapies, PDT has the advantage of being noninvasive and capable of field treatment.
It is also associated with quicker recovery periods and excellent cosmetic results.
Because of these benefits, PDT is being evaluated as a potential treatment option for many
dermatologic conditions and has been shown to be effective for certain nonmelanoma skin
cancers. Although research is still limited, PDT might also have a therapeutic benefit for
cutaneous T-cell lymphoma, acne, psoriasis, leishmaniasis, and warts, among others. This
article is a review of the clinical applications of PDT in dermatology and summarizes the
current evidence in literature describing its efficacy, safety, and cosmetic outcome.
Semin Cutan Med Surg 30:199-209 Published by Elsevier Inc.
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Dec
2011
Vol. 30. No. 4
Photoprotection in the Era of Nanotechnology
Commercial sunscreen based on nano-sized titanium dioxide (TiO2) and zinc oxide (ZnO)
delivers superior UV protection and reduces whitening on skin compared to the older
generations of inorganic sunscreens. This review discusses the historical use of nano-sized
TiO2 and ZnO in sunscreen and the relationship between UV attenuation and the primary
particles, aggregates and agglomerates that make up these inorganic oxides. In addition we
reviewed the recent safety concerns surrounding these materials, specifically, percutaneous
penetration of TiO2 and ZnO nanoparticles through human skin and their potential to
cause phototoxicity.
Semin Cutan Med Surg 30:210-213 © 2011 Elsevier Inc. All rights reserved.
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Dec
2011
Vol. 30. No. 4
Ultraviolet A Radiation: Its Role in Immunosuppression and Carcinogenesis
Ultraviolet A (UVA) radiation is immunosuppressive and mutagenic in humans and carcinogenic
in animals. UVA suppresses immunity with a bell-shaped dose response. At doses
equivalent to 15-20 minutes of sun exposure at noon, UVA contributes to approximately
75% of sunlight-induced immunosuppression. A recent action spectrum, indicating that
360-380 nm but not 320-350 nm UVA suppresses immunity in humans, suggests an
important role for reactive oxygen species. UVA also causes an energy crisis in cells, and
normalization of adenosine triphosphate with nicotinamide prevents UVA immunosuppression.
UVA activation of the alternative complement pathway and defects in memory T-cell
development are also involved. Human skin cancers contain mutations in the p53 and BRM
genes that are consistent with being induced by UVA. UVA is also mutagenic in human skin
equivalents. The basal layer of human skin is more susceptible to UVA-induced mutations
than the upper layers. Because skin cancers arise from these basal proliferating cells, this
finding is likely to be important and could be attributable to low levels of the DNA repair
enzyme OGG1 in basal cells. UVA is therefore likely to make a larger contribution to
UVA-induced skin carcinogenesis in humans than is predicted by small animal models as
the result of being immunosuppressive and mutagenic for basal keratinocytes.
Semin Cutan Med Surg 30:214-221 © 2011 Elsevier Inc. All rights reserved.
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