[The role of streptococci in psoriasis].

Infections with Streptococcus pyogenes are highly relevant among the environmental factors that contribute to first onset or relapses of psoriasis in predisposed individuals. Streptococcal angina or pharyngitis, but also perianal streptococcal dermatitis, vulvovaginitis or balanoposthitis are potential causes. Several mechanisms such as molecular mimicry or superantigens may be involved. Many patients develop a chronic streptococcal infection or colonization that may result from the ability of streptococci for intracellular uptake and persistence in epithelial cells. Whether and under what conditions a curative treatment of streptococcal infection by tonsillectomy or antibiotic treatment may affect the course of psoriasis, as proposed by several observations, needs to be determined in more detail by clinical trials.