|
Fig. 3.8. Wrinkling and
dyspigmentation are commonly
observed features of photoaging
in Caucasian skin |
Wrinkling and dyspigmentation are commonly observed features of photoaging in Caucasian skin (Fig. 3.8). Warren studied photoaging in Caucasian women ages 45–51 with skin types I–III who resided in an area of intense sunlight: Arizona [36]. The investigators, after viewing photographs of nine Caucasian women who had received more than 12 h/week of sun exposure for 10 years’ duration, estimated their mean age to be 58.2 years. This contrasts with an estimated mean age of 53.7 years for 13 Caucasian women who had experienced less than 2 h/week of sun exposure. Additionally, the women with more sun exposure had more wrinkles in the crow’s feet area as well as on the remainder of the face compared with those with less exposure. In the study, the total length of all furrows and lines (wider that 0.5 mm and longer that 5.0 mm) was summed for each group. Sun exposure increased the total wrinkle length with the women with greater exposure for a total wrinkle length of 75.7 cm compared with the low-exposure group,with 53.5 cm total wrinkle length.
Dyspigmentation is a major component of photoaging observed in white skin [37]. Dyspigmentation not readily observable becomes significantly more prominent under Wood’s light examination or UV photography.Discrete and mottled hyperpigmentation under normal and UV photography is seen in Fig. 3.9a,b,
|
Fig. 3.9a,b. Discrete and mottled
hyperpigmentation under normal
photography (a) and ultraviolet
(UV) photography (b).
Photographs are courtesy of
George Faraghan, Faraghan
Medical Photography,
Philadelphia, PA, USA |
which are courtesy of George Faraghan, Faraghan Medical, Philadelphia,PA,USA.One of the manifestations of dyspigmentation in photoaged white skin is mottled, irregular areas of pigmentation [38]. The mottled appearance correlates with areas of hyperpigmentation with irregular distribution of melanocytes along the basement membrane. This is associated with a heterogeneous distribution of melanosomes within the keratinocytes and adjacent areas of hypopigmentation with decreased melanocytes and melanosomes [39].
Another manifestation–freckles, or ephelides– are small, brown macules on sun-exposed skin that darken and increase in number with more intense sun exposure during the summer months. They appear in fair-skinned individuals and genetically predisposed children. Pigmented seborrheic keratoses occur as a manifestation of aged skin but seemingly occur less frequently on sun-exposed white skin compared with Asian skin. Likewise, dermatosis papulosa nigra also appear to occur less often in white skin compared with African American skin.
Solar or actinic lentigines appear during the forth through sixth decades in sun-exposed skin. They are a readily apparent sign of photoaging in white skin and appear on the face, chest, extensor forearms, and dorsa of the hands (Fig. 3.10). There is variation in their size, ranging from several millimeters to over a centimeter, as well as in the regularity of their borders. The incidence of solar lentigines increases
|
Fig. 3.10. Solar lentigines and
other pigmentary manifestations
of photoaging on the chest of a
Caucasian woman |
with age, affecting more than 90% of whites older than 50 years [37]. They are related to a tendency to freckling and sunburns after the age of 20 years [40]. They are usually numerous and may be accompanied by adjacent patchy hypopigmentation, which involves a decrease in the number of melanocytes associated with a reduction in the production of mature melanosomes. This results in a mottled appearance of the skin [41].Lentigines darken significantly after exposure to sunlight [42]. The differential diagnosis of lentigines includes other pigmented lesions, including lentigo maligna, pigmented actinic keratoses, pigmented basal cell carcinomas, and flat or macular seborrheic keratoses. Whereas solar lentigines occur in all skin types, the reticulated black solar lentigo occurs primarily in sun-exposed skin of very fairskinned whites [43]. It resembles a spot of ink on the skin with irregular margins and a reticular pattern. Black solar lentigines are considered a rare variant of actinic lentigines. They are few in number in contrast with the large number of lentigines, and they must be distinguished from melanoma.
Hypomelanosis is observed in Caucasian skin, although it may not be as readily apparent in white skin.Guttate hypomelanosis is characterized by multiple, small, depigmented macules on the anterior surface of the legs, lower abdomen, and arms [44]. The macules are circular with well-defined borders. In summary, in white skin, in addition to wrinkling, ephelides, lentigines, and mottled hyperpigmentation were the major pigmentary alterations demonstrated in several studies.
