Unspecific increase of antistreptolysin-O titer in acute guttate psoriasis.

An acute streptococcal infection is well-known to be a predisposing factor in acute guttate psoriasis. This study also revealed a high ASO titer in 11 of 13 patients at first examination. However, a non-specific ASO increase due to non-immunological reaction of serum lipoproteins with antistreptolysin-O, was found in 5 of these patients who visited our clinic at the evolving phase, 2 or 3 weeks after onset of the eruption but was no longer observed at 5-6 weeks and thereafter. On the other hand, specific ASO increase, which was not related to lipoproteins, was observed first in some patients at 3-4 weeks and at 7-10 weeks in all patients examined. These observations suggest the role of streptococcal lipoprotein alteration in the occurrence of this disease.