Journal of Cosmetic Dermatology, 12, 187--194 Neodymium-yttrium aluminum garnet laser versus pulsed dye laser in erythemato-telangiectatic rosacea: comparison of clinical efficacy and effect on cutaneous substance (P) expression Samar Abdallah M Salem, MD, 1 Nermeen SA Abdel Fattah, MD, 1 Samah MA Tantawy, MBBCh, 1 Nafissa MA El-Badawy, MD, 2 & Yasser A Abd El-Aziz, MD 3 1 Department of Dermatology and Venereology, Faculty of Medicine, Ain Shams University, Cairo, Egypt 2 Department of Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt 3 Department of Plastic Surgery, Faculty of Medicine, Ain Shams University, Cairo, Egypt Summary Background Different laser systems are reported to be effective in treatment of telangiectasia and erythema, but comparative studies on 1064-nm neodymium- yttrium aluminum garnet (Nd-YAG) laser and pulsed dye laser (PDL) in treatment of erythemato-telangiectatic rosacea are lacking. Substance (P) is implicated in rosacea pathogenesis. Objectives To compare the effect of Nd-YAG laser and PDL on erythemato- telangiectatic rosacea, both clinically and immunohistochemically on cutaneous substance (P) expression. Methods This split-face comparative study included 15 patients with erythemato- telangiectatic rosacea treated on the right side with Nd-YAG laser and on the left side with PDL: three sessions, 4 weeks apart. Evaluation of the patients was done using erythema and telangiectasia grading scores, patient’s self-assessment, physicians’ clinical assessment of the patient, and immunohistochemical assessment of substance (P). Results One month after the three laser sessions, excellent response was achieved in 73.3% of patients after Nd-YAG and in 53.3% of patients after PDL with significantly lower substance (P) concentration after Nd-YAG laser than after PDL. Positive correlations were found between the decrease in erythema and telangiectasia grading scores and the decrease in substance (P) concentration. Conclusions The use of Nd-YAG laser and PDL appears to be safe and effective measures in treatment of erythemato-telangiectatic rosacea. Both types of laser decrease the concentration of substance (P) in the skin. This effect is more pronounced with Nd-YAG laser. Keywords: Neodymium-yttrium aluminum garnet laser, Nd-YAG, pulsed dye laser, PDL, rosacea, substance (P) Introduction Rosacea is a common chronic cutaneous disorder characterized by flushing, persistent erythema, telangi- ectasia, papules, and pustules usually confined to the central portion of the face. 1 It occurs most often in fair-skinned females between 30-60 years old. 2 Correspondence: Nermeen S A Abdel Fattah, MD, Associate professor of Dermatology and Venereology, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt. E-mail: nermeensamy2000@yahoo.com Accepted for publication March 12, 2013 © 2013 Wiley Periodicals, Inc. 187 Original Contribution