Yes, it is possible for rashes to appear on the thighs and buttocks. If you have noticed itching and the rash seemed to have appeared after scratching, it may be a sign of an allergic reaction. It is important to avoid scratching as it can worsen the rash. Using a fragrance-free moisturizer like Aveeno can help soothe the skin and applying a cool wet cloth can also provide relief. If the itching is severe, you may consider taking an antihistamine after consulting with a pharmacist. It is also a good idea to wash any clothing or bedding that may have come in contact with the skin to prevent further irritation. Consider if there have been any recent activities or new products that may have triggered the rash.