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Hives are localized, raised red areas in the superficial portion of the skin that may join together to form larger lesions. Hives are closely related to angioedema.
Hives, also called urticaria, are relatively common with at least 20% of the population having had at least one episode during their lifetime. Although seen in all ages, they seem to be more prevalent among young adults. The reaction involves the release of histamine from either mast cells or basophils causing an IgE (immediate type) mediated antibody response.
Acute urticaria lasts from 1 to 7 days and treatment is not usually needed except to reduce the itching. The inciting agent must be dealt with, be it food, external agent or an emotion. In severe cases, epinephrine, as found in a bee sting kit, may be required.
In cases of chronic urticaria of over three weeks' duration, 50% of patients experience spontaneous remission within two years, even though in the majority of cases the cause is never identified.
While hives develop on the skin's surface, angioedema is a swelling of the deeper layers of the skin. It most often occurs on the hands, feet and face. In severe cases, normal breathing or swallowing can be blocked and emergency measures must be taken. This can occur if a person is extremely allergic to a specific food or drug.
Hives and angioedema may appear together or separately on the body. Angioedema usually lasts one or two days, and may reoccur with or without hives over an indefinite period of time.
Hereditary angioedema is a rare inherited disease which can be fatal in some cases and in this respect differs from other types of chronic angioedema. Swelling can occur in the airways, such as the larynx, tongue and throat, as well as on the face and other extremities. It has been demonstrated that a blood protein deficiency is the cause of this inherited illness.
Angioedema without a history of urticaria can be caused by certain drugs (ACE inhibitors), certain malignancies, and by an inherited enzyme deficiency (C1 esterase inhibitor deficiency). Symptoms of the hereditary enzyme deficiency problem typically include attacks of abdominal pain, vomiting, upper airway obstruction and visible non-itchy angioedema. This relatively rare disease requires treatment different from that of chronic urticaria and angioedema.
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Achlorhydria: The complete absence or failure of stomach acid secretion.
Acute: An illness or symptom of sudden onset, which generally has a short duration.
Allergy: Hypersensitivity caused by exposure to a particular antigen (allergen), resulting in an increased reactivity to that antigen on subsequent exposure, sometimes with harmful immunologic consequences.
Anaphylactic: Intense allergic reaction to a foreign substance.
Angioedema: Recurring attacks of transient, subcutaneous edema (water retention/swelling of tissue), often due to an allergic reaction.
Antibody: A type of serum protein (globulin) synthesized by white blood cells of the lymphoid type in response to an antigenic (foreign substance) stimulus. Antibodies are complex substances formed to neutralize or destroy these antigens in the blood. Antibody activity normally fights infection but can be damaging in allergies and a group of diseases that are called autoimmune diseases.
Autoimmune Disease: One of a large group of diseases in which the immune system turns against the body's own cells, tissues and organs, leading to chronic and often deadly conditions. Examples include multiple sclerosis, rheumatoid arthritis, systemic lupus, Bright's disease and diabetes.
Bacteria: Microscopic germs. Some bacteria are "harmful" and can cause disease, while other "friendly" bacteria protect the body from harmful invading organisms.
Basophil: The basophils account for about 1% of the granulocyte count (60 to 75% of the white blood cells). They release chemicals such as histamine and play a role in the inflammatory response to infection.
Cancer: Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Candidiasis: Infection of the skin or mucous membrane with any species of candida, usually Candida albicans. The infection is usually localized to the skin, nails, mouth, vagina, bronchi, or lungs, but may invade the bloodstream. It is a common inhabitant of the GI tract, only becoming a problem when it multiplies excessively and invades local tissues. Growth is encouraged by a weakened immune system, as in AIDS, or with the prolonged administration of antibiotics. Vaginal symptoms include itching in the genital area, pain when urinating, and a thick odorless vaginal discharge.
Chronic: Usually Chronic illness: Illness extending over a long period of time.
Collagen: The primary protein within white fibers of connective tissue and the organic substance found in tendons, ligaments, cartilage, skin, teeth and bone.
Enzymes: Specific protein catalysts produced by the cells that are crucial in chemical reactions and in building up or synthesizing most compounds in the body. Each enzyme performs a specific function without itself being consumed. For example, the digestive enzyme amylase acts on carbohydrates in foods to break them down.
ESR: Erythrocyte Sedimentaion Rate is a screening test and not considered diagnostic for any particular disorder. It is useful in detecting and monitoring inflammatory conditions, tuberculosis, tissue necrosis (tissue death), connective tissue disease, or an otherwise unsuspected disease in which symptoms are vague or physical findings are minimal.
Hepatitis B: A serious viral infection with the potential for long term consequences. It is caused by a DNA virus that has been found in virtually all body secretions and excretions. However, only blood, saliva, semen and vaginal fluids have been shown to be infectious. Transmission occurs through sexual contact, blood-to-blood contact (blood products, needle sharing, etc.), and from infected mother to infant. Virtually all affected infants and children, and many adults, receive a lesser, even symptom-free, infection. Symptoms, when present, tend to be more severe and prolonged than those for Hepatitis A: initially flu-like, with malaise, fatigue, muscle pain and chest pain on the right side. This is followed by jaundice (slight skin yellowing), anorexia, nausea, fatigue, pale stools, dark urine and tender liver enlargement, but usually no fever.
Histamine: A chemical in the body tissues, produced by the breakdown of histidine. It is released in allergic reactions and causes widening of capillaries, decreased blood pressure, increased release of gastric juice, fluid leakage forming itchy skin and hives, and tightening of smooth muscles of the bronchial tube and uterus.
Hydrochloric Acid: (HCl): An inorganic acidic compound, excreted by the stomach, that aids in digestion.
Hypochlorhydria: The condition of having low hydrochloric acid levels in the stomach, often the cause of digestive disorders.
Hypothyroidism: Diminished production of thyroid hormone, leading to low metabolic rate, tendency to gain weight, and sleepiness.
Immune System: A complex that protects the body from disease organisms and other foreign bodies. The system includes the humoral immune response and the cell-mediated response. The immune system also protects the body from invasion by making local barriers and inflammation.
Microgram: (mcg): 1/1,000 of a milligram in weight.
Protein: Compounds composed of hydrogen, oxygen, and nitrogen present in the body and in foods that form complex combinations of amino acids. Protein is essential for life and is used for growth and repair. Foods that supply the body with protein include animal products, grains, legumes, and vegetables. Proteins from animal sources contain the essential amino acids. Proteins are changed to amino acids in the body.
T4: Thyroxin, thyroid hormone also prepared synthetically, for treatment of hypothyroidism and myxedema.
Thyroid: Thyroid Gland: An organ with many veins. It is at the front of the neck. It is essential to normal body growth in infancy and childhood. It releases thyroid hormones - iodine-containing compounds that increase the rate of metabolism, affect body temperature, regulate protein, fat, and carbohydrate catabolism in all cells. They keep up growth hormone release, skeletal maturation, and heart rate, force, and output. They promote central nervous system growth, stimulate the making of many enzymes, and are necessary for muscle tone and vigor.
Urticaria: Commonly known as hives, urticaria is one of the most common dermatological conditions seen by allergists. Urticaria is not just an allergic disease, however. It can be caused by metabolic diseases, medications, infectious diseases, autoimmune disease, or physical sensitivity. Traditional allergies to foods or medications as well as viral illness are frequent causes of acute urticaria which usually lasts only a few hours but may last up to 6 weeks. Chronic urticaria (lasting more than 6 weeks) is more complex, given the vast number of potential triggers. Symptoms include sudden onset; initial itching; then swelling of the surface of the skin into red or skin-colored welts (wheals) with clearly defined edges; welts turn white on touching; new welts develop when the skin is scratched; usually disappear within minutes or hours. Welts enlarge, change shape, spread or join together to form large flat raised areas.
Virus: Any of a vast group of minute structures composed of a protein coat and a core of DNA and/or RNA that reproduces in the cells of the infected host. Capable of infecting all animals and plants, causing devastating disease in immunocompromised individuals. Viruses are not affected by antibiotics, and are completely dependent upon the cells of the infected host for the ability to reproduce.