I had never heard of this until now:
Getting a streptococcal infection in your throat—known as strep throat—can sometimes trigger a psoriasis flare, or even lead to new onset of the disease. In some of these cases, removing the tonsils can be a one-two punch, knocking out the throat infection and psoriasis.
But it may not be time to sign up for a tonsillectomy just yet. A new review of available data found that, although many psoriasis patients who had their tonsils removed did improve, more research is still needed before doctors can say for sure who can benefit most from the procedure, and how long the improvement will last.