A stye is a red, painful lump near the edge of the eyelid that may look like a boil or a pimple. It is caused by a bacterial infection in the oil-producing glands in the eyelids. The bacterium staphylococcus is commonly responsible for most of these infections. Dead skin cells and bacteria from the skin can get trapped on the edge of the eyelid, leading to the development of a stye. Touching the eyes with unwashed hands, inserting contact lenses without thoroughly disinfecting them or washing hands first, leaving on eye makeup overnight, and using old or expired cosmetics can increase the risk of developing a stye. Individuals with blepharitis, which is chronic redness on the edge of the eyelid, are also more likely to get styes. To reduce swelling and help the stye heal, a clean flannel soaked in warm water can be held against the eye for 5 to 10 minutes, repeated 3 or 4 times a day. Painkillers such as paracetamol or ibuprofen can be taken to relieve pain. Bursting a stye or removing an eyelash should not be attempted as it can spread the infection. If the stye does not start to improve after 48 hours, or redness and swelling involves the entire eyelid or extends into the cheek or other parts of the face, a doctor should be contacted.