Introduction: Ms. Chen is an expectant mother who is 28 weeks pregnant. Half a month ago, she discovered a small red bump on her lower abdomen, which was so itchy that she couldn\’t sleep all night. Ms. Chen’s family bought anti-itch ointment, but they did not dare to use it for fear of affecting the fetus. Ms. Chen is an expectant mother who is 28 weeks pregnant. Half a month ago, she found a small red bump on her lower abdomen, which was itchy.