Mycological Efficacy and Safety of Ketoconazole 2% Shampoo With a Seven-Day Versus Three-Day Treatment Duration in Pityriasis Versicolor

The goal of this clinical study is to find out whether using ketoconazole 2% shampoo for seven days works better than using it for three days in treating pityriasis versicolor. The study will also evaluate the safety of both treatment durations. The main questions this study aims to answer are: * Does treatment with ketoconazole 2% shampoo for seven days result in better mycological efficacy compared with three days of treatment in patients with pityriasis versicolor? * Does treatment with ketoconazole 2% shampoo for seven days lead to better clinical improvement compared with three days of treatment? * Are there differences in side effects between the seven-day and three-day ketoconazole 2% shampoo treatment regimens? * Are there differences in dermoscopic features of pityriasis versicolor before and after treatment with ketoconazole 2% shampoo when used for seven days compared with three days?