Hives on the chest, or urticaria, typically result from allergic reactions, according to MedlinePlus. In some cases, urticaria occurs due to infections, drugs, autoimmune diseases or malignancy.
Urticaria is characterized by red, itchy bumps that appear on the chest, says MedlinePlus. An allergic reaction often triggers the production of chemicals such as histamine, which go into the bloodstream. The release of histamine and other chemicals into the blood causes symptoms such as itching and swelling and leads to the occurrence of hives.
Individuals who are allergic to certain substances and those with hay fever may suffer hives, notes MedlinePlus. Animal dander, pollen, medications and insect bites are common triggers. Milk, eggs, nuts, fish and shellfish can also cause hives. In some cases, people who are emotionally stressed, perspiring too much, exercising, or exposed to extreme cold or hot temperatures develop hives.
Mild hives often resolve without the need for medical treatment, states MedlinePlus. Doctors advise individuals with hives to avoid taking hot baths or showers and refrain from wearing tight clothes to alleviate symptoms. Diphenhydramine or other antihistamine medications are sometimes prescribed for people with hives. In severe cases where the swelling affects the throat, a steroid or epinephrine shot may be required, as hives can block the airway in the throat and disrupt normal breathing.