I had a look around and there's some indication it may even act as a preventative.
Lately, it’s been determined that a significant percentage of cats affected by these eosinophilic diseases* respond well to Zyrtec.
*Eg: oral inflammation, upper lip lesions, eosinophilic plaques (crusty sores), intestinal ulceration, bronchitis, tracheitis and astham, among other problems.
Zyrtec (cetirizine) is an antihistamine approved for use in humans to treat allergy symptoms. In veterinary medicine it’s used in both cats and dogs for the same indication ... and more.