The correct spelling of the phrase, "wast allergic to," is actually "was allergic to." This common mistake often occurs due to the similarity in sound between the pronunciation of "was" and "wast" in some dialects. In phonetic transcription, "was" is pronounced as /wʌz/, while "wast" is pronounced as /wɑst/. It's important to pay attention to spelling and pronunciation to avoid confusion and ensure clear communication.