It is important that your child receive treatment if diagnosed with strep throat. Treatment with antibiotics usually can prevent rheumatic fever. Although it is rare, some children with strep develop rheumatic fever, which causes abnormality of the heart valves and inflammation of the joints. Treatment also will prevent other rare, but possibly serious complications from a strep infection. Also if your child is not treated, or not treated long enough, they may continue to spread the infection to other members of your family and to other children.