Hives are a common result of allergic reactions. In addition, physical factors, systemic diseases and hormonal changes can also result in hives.
Hives or wheals are raised pale or reddish skin swellings usually accompanied by itching
. They arise due to release of histamine and other substances from the mast cells. The swellings may be small and appear one after another. They may coalesce together resulting in bigger swellings. The skin usually appears normally once the lesions subside.
In some cases, hives may last for between a few hours to up to 6 weeks. This condition is referred to as acute urticaria. Chronic urticaria, on the other hand, is a condition where the person suffers from recurrent episodes of hives for more than 6 weeks.
Hives are a common consequence of an allergic reaction. In some cases, however, a non-allergic cause may be involved.
Causes of hives include: Food
: Hives can occur following intake of certain foods in sensitive individuals. Foods that are commonly associated with hives include peanuts, eggs, milk, shellfish and fish. Food or food additives that contain histamine or bring about the release of histamine like strawberries, tomatoes, preservatives, and coloring agents are also associated with the development of hives. The hives usually arise soon after food intake and disappear within a few minutes to hours. Medications
: Medications like penicillin, aspirin, ibuprofen, naproxen, radiocontrast dyes, blood pressure medications and antibiotics like vancomycin often cause hives. The hives may be due to a direct effect of the medications on the mast cells or through an allergic mechanism. A history of recent intake of these medicines or a recent change in medications can be elicited from these patients. Insect Bite
: Following an insect bite, a small hive appears at the site. In case of bedbugs, the hives appear in a straight line. Contact Allergen
: Direct contact with substances like latex in gloves can produce hives due to allergy. Environmental Factors
: Presence of allergens in the environment like pollen and animal dander can produce hives. Anaphylaxis
: A patient also develops hives in an anaphylactic reaction. The patient shows the presence of additional features like abdominal pain, dizziness, shortness of breath, a fall in blood pressure and a fast heart beat. Physical Factors
: Physical factors like sunlight, cold, vibration, or even water can cause hives. Prolonged pressure on the skin due to tight underwear, shoes and belts can result in hives. Exercise or any other trigger that increases core body temperature, as well as emotional stress can also result in chronic urticaria. In some cases, stroking or rubbing a normal appearing skin results in urticaria in a straight line; this phenomenon is referred to as dermographism. Systemic Conditions
: Autoimmune conditions (conditions where the body produces antibodies against self) are often associated with chronic urticaria. These include thyroid diseases like Hashimoto’s thyroiditis, systemic lupus erythematosus, vasculitis (inflammation of blood vessels), hepatitis (inflammation of the liver) and lymphoma (a type of blood cancer). Infections such as those affecting the kidney, sinuses or gallbladder can also result in urticaria. These conditions should be ruled out while evaluating a patient for chronic urticaria. Hormonal Factors
: Hives may occur during different phases of the menstrual cycle. A history of a cyclic pattern of appearance of the hives in a female patient helps to diagnose the condition. Such hives may also occur following intake of oral contraceptive pills.
Frequently Asked Questions1. Which doctor should I visit in case I suffer from hives?
You should visit a skin specialist, also called a dermatologist, in case you suffer from hives.2. What are the medications used to treat urticaria?
Urticaria is often a self-limiting condition and does not require any treatment. Patients with chronic urticaria may require some investigations to rule out a systemic cause of urticaria. The patient should be reassured that urticaria is usually not due to a serious cause. Antihistamines are used to treat urticaria. In non-responding cases, other drugs like H2 blockers, leukotriene receptor antagonists or corticosteroids may be tried.