Allergic reaction? Cold sore? other?

Just wanted to update this. It was a yeast infection. I diagnosed it myself via the miracle of the internet and it's been healed for a few weeks. It turns I should have gone to my dentist -- I told him about it the other day when I was there for a checkup, to explain why I went for about a month without flossing my back teeth, and he knew exactly what I was talking about and how to treat it.

Backing up to the visit to urgent care and getting the prednisone Rx -- a few days later I went to the dermatologist. She wasn't sure what it was, considered various possible causes including the coxsackie virus, and concluded it was probably an allergy. She gave me an Rx for a steroid ointment. I mentioned that I had considered putting zinc oxide cream (same stuff as in diaper cream) on the cracks in the corners of my mouth to protect the skin so it would heal. She said that would be okay and gave me some samples of a zinc oxide cream with an antifungal ingredient (miconazole). I filled the Rx for the steroid ointment and started using it. It helped somewhat but not completely.

A few weeks later I had my appointment with the allergist. I described everything that had happened and showed him the photos of the white spots from the outbreak on Sept 8. He said it definitely was not an allergy. He didn't know what it was but thought most likely it was herpes simplex -- a continuation of the cold sore. By this time the white spots were few and far between but the cracks in the corners of my lips continued -- they'd heal, then the skin would crack again, over and over. Then a few days after seeing the allergist I had another outbreak of the white spots.

At this point I went back to the internet, and found a likely answer. It turns out the key was the chronic cracked skin in the corners of my mouth. I had been focusing on the white spots on my lips but had not found anything at all online about them. I had described the cracked corners to all the doctors but they also focused on the white spots. Since I was unable to find anything about what seemed to be the primary symptom, I looked up the secondary symptom and found that it had a name -- angular cheilitis. There were several possible causes, one of which was a fungal/yeast infection. So I found the zinc oxide samples that the dermatologist had given me and started using it in the corners of my lips and around the edges. Within a few days everything cleared up.

This was one of the websites that I found helpful: http://www.dermnetnz.org/site-age-sp...cheilitis.html

My theory is that initial cold sore/Abreva/Aquaphor incident created an environment that allowed a secondary yeast infection to develop. Judging from the websites that helped me figure out what was going on, I think the dermatologist should have been able to diagnose it correctly. It never occurred to me that the dentist would have able to help.