If they didnt go away when you pushed < i'm almost 100 % positive its something she has come in contact with. (and not injested or had enter her body)
Also...just because a product is "all natural" dosent meant they cant have a allergic reaction to it. (learned that the hard way).
Didnt mean that in a know it all...smart aleck way > (sorry if it read that way).
As to the detergent... even though its free and clear..its possible there is "some sort of agent" she is having a reaction to...or the fabric softner.
No telling. I'd just eliminate possible suspects , until you find what it is.
But again..I'm no expert..and It could totally be something else alltogether.
For your sake (and hers...I hope that she isnt the few pups that has what looks to be a external reaction, but its actually an internal agent aka food or what not) all that swithcing does tend to get EXPENSIVE.
Crossing fingers you and vet figure it out soon, and get poor icthy some relieve.