Intense pulsed light in photoaging: a clinical, histopathological and immunohistochemical evaluation.

BACKGROUND Intense pulsed light has been used in the treatment of photoaging without a full understanding of its mechanism of action. OBJECTIVE To study the effect of intense pulsed light on photoaging and on the skin immune response by means of a clinical and histopathological study, evaluating Langerhans cells (CD1), expression of intercellular adhesion molecule, of CD4 and CD8 lymphocytes and quantification of collagen and elastic fibers. METHODS In 2006 a total of 26 patients, aged 40 to 65 years, with phototypes II to III (Fitzpatrick scale), were treated for photoaging using intense pulsed light in five sessions with a monthly interval. All the patients were subjected to histological and immunohistochemical evaluation 6 months after treatment. RESULTS At the end of the treatment clinical improvement was observed in 76.92% of cases. This improvement was associated to a significant increase of collagen (51.33%) and elastic (44.13%) fibers. Intense pulsed light treatment led to a reduction of CD4 lymphocytes and did not alter the amount of CD8 lymphocytes. It also led to a significant increase of small, nonectatic blood vessels, positive intercellular adhesion molecule. CONCLUSION Facial treatment with intense pulsed light promoted major clinical improvement that was confirmed by histological examination of the skin. This technique is a good treatment option for skin photoaging because it is non-ablative, safe and effective.