Frequent throat irritation and sneezing from chalk dust are likely due to ongoing irritation or allergy rather than infection, so antibiotics such as azithromycin may not provide lasting relief. Try to reduce exposure by wearing a mask while teaching, using marker boards if possible, and keeping the classroom well ventilated. Warm fluids and salt water gargles can soothe the throat, and avoiding triggers can help control symptoms. If the problem continues, consult a doctor for proper evaluation and long-term management.