Study of the Effect of Fractional co2 Laser Versus Q Switched:NdYAG Laser in the Treatment of Acanthosis Nigricans

This prospective randomized comparative split study will be conducted at the outpatient clinic, Dermatology department, Faculty of Medicine, Cairo University and will include 20 patients with acanthosis nigricans in otherwise healthy individuals which will be recruited and assessed for eligibility for inclusion according to the above criteria. -Evaluation: All patients will be subjected to: Pre-operative preparation: * Informed written consent will be taken from every patient prior to the study. * Detailed history taking including onset, course, duration of the disease and occupation (sun-exposed or not), predisposing factors, history of keloid tendency, associated diseases and previous treatments. * Assessment of skin type, BMI, degree of AN, HbA1C, site of lesions in all patients and degree of improvement. * Photography: will evaluate the clinical response to treatment for each patient Photos will be taken before starting the study, before every session, and two weeks after the last session. * Melanin index (MI) will be measured using reflectance spectrophotometer in order to assess the degree of hyperpigmentation before starting the study and two weeks after the last session. Research Template 8 Final Version: April 2019 * Acanthosis Nigricans Area and Severity Index (ANASI) score (Zaki et al., 2018) will be done for all patients before starting the study and two weeks after the last session. * Patient satisfaction score will be assessed before starting the study and two weeks after the last session. * Patient evaluation (clinical percentage of improvement). Operation : One side of the affected area will be randomly assigned to fractional CO2 laser every four weeks for three months. The other side will be assigned to Q-switched Nd:YAG laser every four weeks for three months. Method of randomization: Using closed envelopes containing cards with fractional CO2 Rt and fractional CO2 Lt and the patient will draw one of them blindly. The assessment will be don