Hives or skin rashes (urticaria) are small patches of red, usually itchy, skin. They are very rare in cats and are most often associated with insect bites or stings or with medications. Hives may develop after inhaling or consuming allergens.

The wheals (eruptions) appear within a few minutes or hours of exposure to the causative agent. In severe cases, the skin eruptions are preceded by fever, poor appetite, or dullness. They can develop on any part of the body but occur mainly on the back, flanks, neck, eyelids, and legs. In advanced cases, they may be found on the mucous membranes of the mouth, nose, lining of the eyes, rectum, and vagina.

Often, hives disappear as rapidly as they arise, usually within a few hours. Treatment may not be required. They may return rapidly if exposure to the cause is not eliminated, however. Treatment may include rapid-acting corticosteroids. If hives are chronic, food or environmental allergens should be considered as potential causes.

Last full review/revision July 2011 by Karen A. Moriello, DVM, DACVD; Thomas R. Klei, PhD; David Stiller, MS, PhD; Stephen D. White, DVM, DACVD; Michael W. Dryden, DVM, PhD; Carol S. Foil, DVM, MS, DACVD; Paul Gibbs, BVSc, PhD, FRCVS; John E. Lloyd, BS, PhD; Bernard Mignon, DVM, PhD, DEVPC; Wayne Rosenkrantz, DVM, DACVD; Patricia A. Talcott, MS, DVM, PhD, DABVT; Alice Villalobos, DVM, DPNAP; Patricia D. White, DVM, MS, DACVD