Hives fall into two main categories: acute and chronic.   

• Acute hives (<6 weeks) 
• Lifetime prevalence: 8 to 20 percent of adults globally^2,3 

• Chronic hives (>6 weeks) 
• Lifetime prevalence: 0.1 to 1.8 percent of adults globally^2,3

Acute hives resolve quickly—most often in a couple of hours to a day.

There are many causes of hives, including extreme temperatures, sun, exercise, viral infections, and stress, along with medications, latex, animal saliva, and insect venom. Occasionally, hives can point to a more serious, rare condition known as mastocytosis, a disorder that is characterized by an increased number of mast cells in the gastrointestinal tract, skin, bone marrow, spleen, liver, and lymph nodes.⁴

The hallmark symptoms of hives may include the following:¹

• Itchy, red skin plaques that can occur alone or in groups on any part of the skin. 
• Wheals (i.e., raised patches of skin surrounded by a red area) that vary in size, change shape, and appear and fade repeatedly as the reaction runs its course. 
• Swelling under the skin (angioedema), present on the lips and/or eyelids and inside the throat. Angioedema can be life-threatening if swelling causes the throat or tongue to block the airway. 

 The following types of allergens may trigger an immune-mediated response: 

• Contact or inhaled allergens (e.g., latex, animal saliva, dust, pollen, mold, dander) 
• Ingested allergens (e.g., peanuts, tree nuts, shellfish, fish, wheat, eggs, milk, soy) 
• Insect venom (e.g., Hymenoptera venom)

If your symptoms are mild, you may not need treatment. Hives and angioedema often clear up on their own. But treatment can offer relief for intense itching, serious discomfort, and/or symptoms that persist.⁶  If the cause of hives can be identified, the best treatment is to avoid the trigger or eliminate it.⁷ 

Antihistamines—available either over the counter or by prescription—are a frequently recommended treatment for hives.⁷  They work by blocking the effect of histamine, a chemical released in the blood stream, which among other substances can be responsible for some of the allergy symptoms.  

  These tips may also help relieve your symptoms:⁶

• Apply a cold washcloth.  Covering the affected area with a cold washcloth can help soothe the skin and prevent you from scratching. 
• Take a comfortably cool bath.  Find relief from itching in a cool shower or bath. Some people may also benefit from bathing in cool water sprinkled with baking soda or oatmeal powder, but this isn't a solution for long-term control of chronic itching. 
• Wear loose, smooth-textured cotton clothing.  Avoid wearing clothing that's rough, tight, scratchy, or made from wool. This will help you avoid skin irritation. 
• Avoid the sun.  When outdoors, seek shade to help relieve discomfort. 

Understanding the instigating factor behind hives is one piece of the puzzle. Discovering whether it is acute or chronic and if it happens alone or in association with other conditions, such as allergies, are also important pieces. These clues can be obtained through a physical exam, detailed medical history, and possibly even the results of specific IgE blood testing. With the right information in place, a healthcare provider can put together a comprehensive management plan to address your symptoms. 

 A blood test—together with an allergy-focused medical history—may help identify underlying allergen triggers.