Tonsillitis is an infection of tonsils. Tonsillitis is common, especially in children. It can happen once in a while or come back again and again in a short period.A common cause is Streptococcus (strep) bacteria, which can also cause strep throat.There are three types: Acute tonsillitis. These symptoms usually last 3 or 4 days but can last up to 2 weeks. Recurrent tonsillitis. This is when you get tonsillitis several times in a year. Chronic tonsillitis. This is when you have a long-term tonsil infection. Symptoms include: Throat pain or tenderness Fever Red tonsils A white or yellow coating on your tonsils Painful blisters or ulcers on your throat Headache Loss of appetite Ear pain Trouble swallowing Swollen glands in your neck or jaw Fever and chills Bad breath A scratchy or muffled voice Stiff neck