Human allergy to cats: A review of the impact on cat ownership and relinquishment.

Cats have become increasingly common as companion animals, and in many countries their popularity now exceeds that of dogs. At the same time, human allergies (including allergy to cats) have been increasing and it has been estimated that globally up to 10-20% of human adults are sensitised to cats. This review summarises the available published data on how human allergy to cats affects cat ownership and considers the implications of the findings on the wider human-cat bond and how adverse effects can be minimised. Online databases were searched for all original studies up to December 2020 that had quantified the impact of human allergy to cats on ownership or relinquishment. Objective quantifiable data appeared to fall into three broad outcomes - (1) choosing to avoid cat ownership; (2) relinquishment of owned cats; and (3) return of cats after acquisition from a rehoming centre. The data retrieved on these topics are the focus of this review. In some studies, data from cats and dogs were combined and these have also been included in the review.