Allergies occur when the immune system has an exaggerated response to normally harmless substances in the environment. Common allergens include foods, pollen, dust mites, pet dander, and insect stings. Symptoms of allergies can vary from mild to life-threatening and include sneezing, coughing, hives, and difficulty breathing. Home remedies for treating allergies include applying sandalwood and lime juice paste to affected areas, drinking mixtures of citrus fruits and vinegar, or consuming carrot juice combined with beetroot and cucumber.