Yikes, have fun with that? At least it’s not contagious, unlike most forms of aphthous stomatis (like cold sores).
I assume to be diagnosed with this condition, you’ve already been tested for Epstein-Barr and cytomegalovirus, but as you’ve seen, it can mimic those two viruses (which many people know from having mono) combined with cold sores (painful little mouth ulcers that hurt much more than their size would suggest they should).
PFAPA, to those who don’t know, is Periodic Fever, Aphthous Stomatitis, Pharyngitis and Adenopathy, and generally presents as, well, exactly what its name implies - periodic fever, “cold sores”, sore throat, and swollen lymph nodes (most often in the throat, just like in mono). It usually lasts a few days at a time, several (3+) times a year.
Generally, it seems to be an autoimmune reaction to a previous infection, and what it isn’t, and how it responds to symptomatic treatment tend to be the defining factors for diagnosis. Once the viruses and genetic or autoimmune conditions that cause similar symptoms are excluded, the patient is generally given a prednisone injection when the fever flares again - if the fever decreases immediately, the patient is diagnosed with PFAPA.
While most patients are diagnosed between 3 weeks and 7 years of age, and the condition almost always resolves on its own by 10 years old, teens and adults are occasionally diagnosed. Teenagers often overcome the condition on their own, though it may take up to two decades. Adults sometimes never overcome it, though their ability to self-treat with prednisone injections and anti-inflammatory medications can minimize the impact to their professional and personal lives.
more on PFAPA: