ASO is an antibody which is generated in response to infection by Group A streptococci. Diseases which cause high ASO titer are rheumatic fever
, scarlet fever
, erysipelas, acute post streptococcal glomerulonephritis.In scarlet fever there is fever, abdominal pain, sore throat but there is a classical sandpapery feel rash which helps in its diagnosis. Rheumatic fever is characterized by appearance of a rash, skin nodules, joint pains, fever, heart problem, and involuntary movements .