Yes, Strep causes sore throats but there are many types of Strep.  Strep is short for Streptococcus which is the genus of the family.  And then there are many species of Streptococcus.  In fact, there are so many species in the family tree they are in groups from “A” to “H”.  Streptococcus pyogenes is the specific organism that causes “Strep throat” but it also causes impetigo.  Streptococcus pneumonia causes ear, sinus, bronchial and lung infections.  Streptococcus faecalis causes urinary infections. 

But the Strep that I think you heard about is Streptococcus salivarius.  As the “species” name implies this is actually part of the normal microbiome in our saliva, in our mouths.  However, when it jumps borders and colonizes the nose and sinuses it can cause mischief.  Researchers at the NIH found that patients with allergic rhinitis who also had the Strep salivarius in their nasal membranes had worsening of their underlying allergies.  Getting rid of the Strep salivarius led to significant improvement in their allergic rhinitis.  It seems that when the Strep salivarius resides in the nose (but not when only in the mouth) it produces inflammatory proteins that work synergistically with the inflammatory mediators produced by allergy.  The end result is a “double whammy”.  The NIH is researching a bacterial selective treatment that will only remove the nasal Strep and not affect the rest of the microbiome.  Stay tuned.