Hives: An Allergic Condition
Authored by Dr.AM Mohan Rao
Introduction Hives is a skin reaction that causes itchy patches which can range from small spots in size to large blotches which can be several inches in diameter. Certain foods, drugs or other substances are known to cause hives. Urticaria is the other name for hives.
A condition called angioedema is also linked to hives. In angioedema the deeper layers of the skin are affected causing it to swell. The skin near eyes and lips is mostly affected. Angioedema and hives are usually harmless and do not leave any marks even without any treatment. Antihistamine drugs are usually given to treat hives and angioedema. Angioedema can be life threatening if the swelling is caused in the throat or tongue as it can block the airway Causes Following are causes of hives and angioedema: • Foods: Shellfish, peanuts, fish, tree nuts, eggs and milk. • Medications: Penicillin, aspirin, naproxen, ibuprofen and blood pressure medications. • Common allergens: Pollen, latex, animal dander and insect stings. • Environmental factors: Heat, cold, water, sunlight, pressure on the skin, emotional stress and exercise. • Underlying medical conditions: Lupus, lymphoma, thyroid conditions, bacterial infections, viral infections like hepatitis, HIV or cytomegalovirus. • Genetics Symptoms The welts which appear on the skin due to hives can be: • Red or flesh colored • Oval or worm like in shape • Intensely itchy • A few millimeters to several inches in diameter
Most of these itchy patches go away within 24 hours while the chronic ones can last for several months or years. Diagnosis First a physical examination of the welts is done by the physician. Medical history is also collected to determine the cause. To further confirm it, a skin allergy test is carried out. The physician also recommends blood test to check the presence of certain blood proteins. If the disease is suspected to be hereditary then the physician recommends blood test to check the presence of certain blood proteins.
Who are at Risk? Factors increasing the risk of hives and angioedema include: • Have had hives or angioedema before • Have had other allergic reactions • Have a family history of hives, angioedema or hereditary angioedema • Have a disorder associated with hives and angioedema such as lymphoma, lupus or thyroid disease. Treatment Mild cases of hives do not need any treatment. The spots clear up themselves. Treatment may be required if there is severe itching or discomfort. The medications used in the treatment of hives and angioedema are: • Antihistamines: These drugs are given to reduce the swelling, itching or other allergy symptoms. • Corticosteroids: These are given orally in severe cases to reduce redness, itching and swelling. • Autoimmune drugs: Autoimmune drugs are prescribed when the antihistamines and corticosteroids are not effective. • Blood protein controllers: In the case of hereditary angioedema, blood protein controllers are given to regulate the levels of blood proteins causing the angioedema. Emergency situations: Emergency treatment with injection of epinephrine is required in a sudden severe attack of hives or angioedema. If there are chances of recurrence of the attack, then a pen like device is given to the patient to inject epinephrine in emergency. Prevention Hives can be prevented by identifying and avoiding the particular circumstance or substance that trigger your skin reaction. If you are allergic to insect venom or insect bites, you may keep antihistamines in your medicine cabinet and take it at the first sign of hives or itching. However, older people with heart disease should double check with their doctor before buying or taking antihistamines.