The virus is not found on routine viral culture. The characteristic lace-like rash and mild nature of the illness are diagnostic. Measles produces a moderate to severe illness before the rash. Scarlet Fever produces a marked sore throat and general illness. Complications and secondary problems.
Arthritis can occur in older patients.
Pain and stiffness can occur in the knees and elbows, ankles and elbows and feet and hands usually bilaterally. It usually follows the rash and persists for 2-4 weeks but disappears without permanent damage in most patients. Reticulocytes, a type of red cell which occurs in very small numbers in normal individuals is affected. This is not noticeable in the blood of normal individuals but is evident in people with anaemia due to chronic red cell loss. Isolated low red cell counts, long lasting low white cell counts and low platelet counts can occur.