Tonsillitis is usually caused by certain bacteria (eg group A beta-haemolytic streptococci) and sometimes viral infections that result in a sore and swollen throat, a fever, white spots at the back of the throat and difficulty swallowing. Usually rest and a course of antibiotics will see it off, but occasionally the infection is very severe and can potentially cause serious problems, or reoccurs very frequently. In these cases a tonsillectomy may be considered – a surgical procedure where the tonsils are removed. The adenoids are less commonly infected but, when they are, they become inflamed and swell to obstruct breathing through the nose and interfere with drainage from the sinuses, which can lead to further infections. In younger people, constant breathing through the mouth can stress the facial bones and cause deformities as they grow, which is why children will sometimes have their adenoid glands removed.