Bug bites and stings
Ice or cold compresses can help relieve the itching from a mosquito bite or bee sting -- as can a dab of baking-soda toothpaste, which has a cooling effect. You can apply a mild hydrocortisone cream to a bite that's persistently itchy or puffy, as long as it's not on the face, neck, or groin area. If you see severe swelling, however, call the doctor.
Rashes from poisonous plants
To soothe the streaky, itchy red rash from poison ivy, oak, or sumac, apply cold compresses or ice packs, or an aluminum acetate solution (such as Burow's solution) or mild hydrocortisone cream. If the rash is severe and unbearable, see your doctor; in some cases, a two-week course of oral steroids may be needed.