Hypnosis, which is generally regarded as an altered state of consciousness associated with concentration, relaxation and imagination, and amongst other characteristics an enhanced responsiveness to suggestion, has long been thought to be effective in the amelioration of various bodily disorders. It has seemed that the state of hypnosis is capable of a bridging or mediating function in the supposed dualism between mind and body. There has been great variation in the experimental and clinical procedures such as type of hypnotic intervention employed, the training of subjects and the timing of the intervention. Also, variability in the type of allergen used and its mode of application is evident. But despite these limitations, many of the studies have shown a link between the use of hypnosis and a changed response to an allergic stimulus or to a lessened bronchial hyperreactivity.

Reference

(1994)Hypnosis and the allergic response
https://pubmed.ncbi.nlm.nih.gov/8073242/