An untold number and types of allergens cause hives. Barb Crabbe, DVM, reviews myths and facts about hives in horses in this article. Animal health pros who deal with horses and their owners will appreciate this article as new information or simply a review. Persons working with FFA or 4-H groups can use this information to position allergy testing and explain first aid for hives.
Source: Horse and Rider, March 2016, page 54. (direct link unavailable)
Just like humans, horses have all kinds of allergies to many different things. Sometimes an allergic reaction can be sudden and severe, while other times it takes its time to cause a wide range of different signs, including a cough, swollen legs, or bumps in the skin we call hives. Because hives are common, everyone has an opinion on them. This article will help navigate the maze of advice and opinions and arm you with some truths behind many of the myths commonly perpetuated.