Introduction

• Whether you are allergic to a food, medicine, or other allergen, you may see that exposure to these substances causes raised welts to appear on the skin. These welts are a form of hives. Hives can occur at anytime, and according to the Mayo Clinic, usually clear up within a week on their own.
  
  

Histamine

• Allergy welts occur due to the release of histamine in the skin. Histamine is a substance that is released by special cells called mast cells. When the skin near mast cells is exposed to an allergen, the body responds by causing mast cells to release the histamine into the affected area which causes swelling.
  
  

Inflammation

• Histamine has unique chemical properties that cause blood vessels in the immediate vicinity to dilate. This makes the walls of these blood vessels more permeable. Unfortunately, this can also cause the blood vessels to leak into the surrounding skin. This leaves raised areas of skin due to swelling, which forms the look of a welt.
  
  

Treatment

• Though most cases of welt causing hives dissapear on their own, there are treatment options to help speed up the process. For mild cases of hives, over-the-counter products such as Benadryl, Zyrtec or Claritin may help reduce the amount of histamine being produced in the affected area. For more severe cases of hives, prescription medications such as Clarinex or Allegra may be used to help stop the production of histamine.