Usually, an “allergy” to tetanus toxoid is anecdotal and not a true anaphylactic reaction to modern tetanus toxoid. Patients often claim to be allergic to tetanus toxoid because of (1) an exaggerated local reaction (which is not an allergy) or (2) a reaction to a tetanus vaccine received many years ago (probably serum sickness from equine tetanus antitoxin). A history of one of these events is not a contraindication to modern tetanus toxoid, Td, or Tdap.
Only an allergist-confirmed severe allergy (e.g., anaphylaxis) to tetanus toxoid should be accepted as a valid contraindication to a modern tetanus-toxoid containing product. A person who has an allergist-confirmed anaphylactic allergy to tetanus toxoid has no recourse for pertussis vaccination because no single-antigen pertussis vaccine is licensed for use in the United States.