What’s going on with these spots on my wall?
My house was built in the 1920s, walls are plaster and lathe. I painted the living room dark teal about five years ago. For the last year I’ve watched these little white spots get bigger - at first I thought I’d missed spots painting but they’re definitely growing. They are located at either end of a step down into the living room and nowhere else. The wall feels solid and sturdy behind them. No dust or debris has fallen from them. There’s no pipes behind the wall. I’m terrified it’s termite activity. The floors were refinished a few years ago and the spots that are white are the only place the floor sealer contacts the painted wall so I guess that’s another possible reason for the discoloration? I don’t want to just paint over it if there’s something serious going on. Any help?