I suppose it could be true but it's a new one on me.
A little more history would help. You took her to the vet for her allergies, and then she had accidents in the house. Did they put her on prednisone? That would explain the accidents.
Is she scratching the flews or her chin? What are you feeding her? What type of bowl does she get her food/water in? Is she itching anywhere else?
In cases of recurrent skin problems, I always recommend visiting an holistic vet. In holistic medicine, skin problems are the sign of an internal imbalance. Your vet buried the symptoms once when he treated the allergies, and now they have returned as the itching of the flews. Treating that without looking at the rest of the picture will bury them again, and they will either turn up elsewhere (ears or feet, maybe) or they will internalize, and you'll see digestive problems, or other systems will be affected that you don't see. A holistic vet will look at the whole picture - diet, environment, history, current condition, stress, genetics, etc. - and treat accordingly, working on the imbalance and not just treating (burying) the symptoms.
In the mean time, aloe vera juice (preserved naturally) is soothing to the skin. Tea tree oil also helps immensely but must be diluted - it is highly toxic full-strength.