According to WebMD, the tonsils are soft masses of tissue located near the back of throat and covered in pink tissue similar to the lining of the mouth. Each tonsil has several pits running through the covering tissue, which doctors call crypts. The tonsils are similar in size and located on opposite sides of the throat.
As KidsHealth points out, tonsils are a part of the lymphatic system and help to fight infection. Tonsils themselves sometimes suffer infection, which leads to their becoming enlarged and red or irritated. Sometimes a white or yellow film covers the infected tonsils. Tonsillitis, the medical term for this condition, sometimes causes sore throat, difficulty swallowing or swollen lymph nodes in the patient's neck. Children should see a doctor to obtain an accurate diagnosis or if they suffer from recurrent sore throats. Doctors typically perform a throat swab to make a diagnosis and to rule out a strep infection.
Some children have enlarged tonsils without any of the other symptoms of tonsillitis. In these children, the tonsils sometimes shrink on their own over several years, according to KidsHealth. If enlarged tonsils cause difficulty in breathing or swallowing, or if a child suffers frequent bouts of tonsillitis, the child's doctor often recommends surgical removal through a tonsillectomy, according to Wikipedia.