A case of baboon syndrome associated with group a streptococcal infection.

We described a 21-year-old Japanese patient with sore throat, fever, and diffuse erythema on the neck, trunk, and limbs. Erythema markedly appeared on the neck, axillary, antecubital, and popliteal fossae. However, other skin signs of scarlet fever such as red strawberry tongue and linear petechial eruption did not appear. Before his visit to our clinic, he had been diagnosed as pharyngitis and treated with cefaclor 750 mg daily for six days. However, the symptoms did not improve. Oral prednisolone of 20 mg daily rapidly improved all the symptoms. Pharyngeal culture grew Streptococcus pyogenes that was sensitive to cefaclor. Laboratory findings showed elevated serum levels of antibody against streptolysin O. Together with the distribution of erythema, culture of Streptococcal pyogenes, and elevated anti-streptolysin O titer, the diagnosis of baboon syndrome associated with streptococcal infection was made. This seems to be the first report of baboon syndrome due to streptococcal infection.