commonly known as hives are itchy wheals caused by an allergic reaction
Hives Hives frequently occur following an infection or as a result of an allergic reaction such as to medication, insect bites, or food.[2] Psychological stress, cold temperature, or vibration may also be a trigger.[1][2] In half of cases the cause remains unknown.[2] Risk factors include having conditions such as hay fever or asthma.[3] Diagnosis is typically based on the appearance. Patch testing may be useful to determine the allergy.[2]