Topical imiquimod improves cosmetic appearance of photoaged skin

Albert M. Kligman, M.D., Ph.D., and Raymond L. Cornelison, Jr., M.D., and colleagues at Oklahoma University Health Science Center report clinical and histological evidence demonstrating anti-aging effects associated with imiquimod treatment.

Cosmetic effect

"The cosmetic effects of this treatment were quite remarkable and the patients were very pleased with the results.

"Currently, imiquimod is a valuable medication for the treatment of precancerous and cancerous skin lesions. The results of this study suggest it has interesting potential for cosmetic use as well," says Dr. Kligman, professor of dermatology, University of Pennsylvania, Philadelphia.

Study specifics

The women participating in the study ranged in age from 33 to 55 years old and were fair-skinned (Fitzpatrick phototypes I or II).

Evaluations of clinical responses to the treatment included subjective and objective measures. Assessments of global improvement in skin appearance by the investigator showed nine (90 percent) of the 10 women benefited with slight or moderate improvement in global appearance, while nine (90 percent) subjects rated the improvement as moderate to great.

In addition, five women selected for having the greatest severity of photodamage underwent additional studies, including hydration assessment with measurement of skin capacitance and hygroscopicity, chromametric assessment and punch biopsies. The hydration studies showed no changes in skin capacitance or water desorption rate constant. Hygroscopicity and water holding capacity improved, but the changes from baseline were not statistically significant.

"These studies indicate that the hydration level below the skin surface was not affected by the treatment, but that there was increased water content in the superficial, desquamating portion of the stratum corneum," Dr. Kligman says.

Study results

The colorimetry studies showed a decrease in mean reflectance indicative of reduced scaling and corresponding to the women's reports of improved surface smoothness.

Histology revealed elimination of epidermal thickening and keratinocyte atypia accompanied by reduced epidermal melanin content and more uniform melanin distribution, which Dr. Kligman notes is consistent with observations of reduced clinical mottling.

Dr. Cornelison and colleagues report similar epidermal histologic changes - but also note effects on the dermis - in their study that evaluated tissue specimens obtained from patients enrolled in a clinical study of imiquimod treatment for lentigo maligna (LM). The subjects in that trial applied imiquimod daily for three months and had pre-and post-treatment biopsies performed to assess LM clearance.

Specimens were available from 26 subjects, and 24 (92 percent) of those patients were determined to be complete responders in terms of LM disappearance. However, semiquantitative grading of a variety of histologic parameters also showed restoration of normal epidermal thickness and melanization as well as significant increased papillary dermal fibroplasia and significantly decreased solar elastosis in 24 patients (92 percent).