Hives

Definition

Hives is an allergic skin reaction causing localized redness, swelling, and itching .

Description

Hives is a reaction of the body's immune system that causes areas of the skin to swell, itch, and become reddened (wheals). When the reaction is limited to small areas of the skin, it is called urticaria. Involvement of larger areas, such as whole sections of a limb, is called angioedema.

Demographics

Many children and adults experience hives at various times during their lives. As hives is not a reportable event, no accurate prevalence statistics are available.

Causes and symptoms

Hives is an allergic reaction. The body's immune system is normally responsible for protection from foreign invaders. When it becomes sensitized to normally harmless substances, the resulting reaction is called an allergy. An attack of hives is set off when such a substance, called an allergen, is ingested, inhaled, or otherwise contacted. It interacts with immune cells called mast cells, which reside in the skin, airways, and digestive system. When mast cells encounter an allergen, they release histamine and other chemicals, both locally and into the bloodstream. These chemicals cause blood vessels to become more porous, allowing fluid to accumulate in tissue and leading to the swollen and reddish appearance of hives. Some of the chemicals released sensitize pain nerve endings, causing the affected area to become itchy and sensitive.

A wide variety of substances may cause hives in sensitive people, including foods, drugs, and insect bites or stings . Common culprits include:

• nuts, especially peanuts, walnuts, and Brazil nuts
• fish, mollusks, and shellfish
• eggs
• wheat
• milk
• strawberries
• food additives and preservatives
• penicillin or other antibiotics
• flu vaccines
• tetanus toxoid vaccine
• gamma globulin
• bee, wasp, and hornet stings
• bites of mosquitoes, fleas, and scabies

Urticaria is characterized by redness, swelling, and itching of small areas of the skin. These patches usually grow and recede in less than a day but may be replaced by others in other locations. Angioedema is characterized by more diffuse swelling. Swelling of the airways may cause wheezing and respiratory distress. In severe cases, airway obstruction may occur.

When to call the doctor

A doctor or other healthcare professional should be called when hives do not spontaneously clear within a day of their appearance or when they include swelling of the throat. If the reactions are severe, as in anaphylactic reaction or shock, immediate medical care is needed.

Diagnosis

Hives are easily diagnosed by visual inspection. The cause of hives is usually apparent but may require a careful medical history in some cases.

Treatment

Mild cases of hives are treated with antihistamines , such as diphenhydramine (Benadryl). More severe cases may require oral corticosteroids, such as prednisone. Topical corticosteroids are not effective. Airway swelling may require emergency injection of epinephrine (adrenaline).

An alternative practitioner will try to determine what allergic substance is causing the reaction and help the person eliminate or minimize its effects. To deal with the symptoms of hives, an oatmeal bath may help to relieve itching. Chickweed (Stellaria media ), applied as a poultice (crushed or chopped herbs applied directly to the skin) or added to bath water, may also help relieve itching. Several homeopathic remedies, including Urtica urens and Apis (Apis mellifica ), may help relieve the itch, redness, or swelling associated with hives.

Prognosis

Most cases of hives clear up within one to seven days without treatment, providing the cause (allergen) is found and avoided.

Prevention

Preventing hives depends on avoiding the allergen causing them. Analysis of new items in the diet or new drugs taken may reveal the likely source of the reaction. Chronic hives may be aggravated by stress, caffeine , alcohol, or tobacco; avoiding these may reduce the frequency of reactions.

Nutritional concerns

Hives may be triggered or worsened by caffeine or alcohol (in adults), or specific allergenic foods, which depend entirely on the patient. Avoiding these substances may reduce the occurrence of hives.

Parental concerns

Parents should monitor their children to ensure that any attack of hives does not involve the throat area. Young children should be encouraged not to stratch their skin too vigorously. If hives are a recurrent problem, parents should keep track of the foods the child eats in an attempt to discover the allergen.

KEY TERMS

Allergen —A foreign substance that provokes an immune reaction or allergic response in some sensitive people but not in most others.

Wheal —A smooth, slightly elevated area on the body surface that is redder or paler than the surrounding skin.

Resources

BOOKS

Duvic, Madeleine. "Urticaria, Drug Hypersensitivity Rashes, Nodules and Tumors, and Atrophic Diseases." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 2475–85.

Frank, Michael M. "Urticaria and Angioedema." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 1610–3.

Leung, Donald Y. M. "Urticaria and Angioedema (Hives)." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 778–80.

Yancy, Kim B., and Thomas J. Lawley. "Immunologically Mediated Skin Disorders." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 331–5.

PERIODICALS

Beltrani, V. S. "Urticaria: reassessed." Allergy and Asthma Proceedings 25, no. 3 (2004): 143–9.

Clarke, P. "Urticaria." Australian Family Physician 33, no. 7 (2004): 501–3.

Dice, J. P. "Physical urticaria." Immunology and Allergy Clinics of North America 24, no. 2 (2004): 225–46.

Grattan, C. E. "Autoimmune urticaria." Immunology and Allergy Clinics of North America 24, no. 2 (2004): 163–81.

Lawlor, F., and A. K. Black. "Delayed pressure urticaria." Immunology and Allergy Clinics of North America 24, no. 2 (2004): 247–58.

Rumbyrt, J. S., and A. L. Schocket. "Chronic urticaria and thyroid disease." Immunology and Allergy Clinics of North America 24, no. 2 (2004): 215–23.

Sheikh, J. "Advances in the treatment of chronic urticaria." Immunology and Allergy Clinics of North America 24, no. 2 (2004): 317–34.

ORGANIZATIONS

American Academy of Dermatology. 930 N. Meacham Road, PO Box 4014, Schaumburg, IL 60168–4014. Web site: <www.aad.org/>.

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007–1098. Web site: <www.aap.org/>.

WEB SITES

"Hives." MedlinePlus. Available online at <www.nlm.nih.gov/medlineplus/ency/article/000845.htm> (accessed January 6, 2005).

"Hives (Urticaria)." San Francisco State University Student Health Service. Available online at <www.sfsu.edu/~shs/skinclinic/urticaria.htm> (accessed January 6, 2005).

"Urticaria (Hives)." American Osteopathic College of Dermatology. Available online at <www.aocd.org/skin/dermatologic_diseases/urticaria.html> (accessed January 6, 2005).

L. Fleming Fallon, Jr., MD, DrPH

Hives

Definition

Hives are an allergic skin reaction causing localized redness, swelling, and itching .

Description

Hives are a reaction of the body's immune system that causes areas of the skin to swell, itch, and become reddened. (The affected areas are called wheals.) When the reaction is limited to small areas of the skin, it is called urticaria. Involvement of larger areas, such as whole sections of a limb, is called angioedema.

Causes & symptoms

Causes

Hives are an allergic reaction. The body's immune system is normally responsible for protection from foreign invaders. When it becomes sensitized to normally harmless substances, the resulting reaction is called an allergy. An attack of hives is set off when such a substance, called an allergen, is ingested, inhaled, or otherwise contacted. It interacts with immune cells called mast cells, which reside in the skin, airways, and digestive system. When mast cells encounter an allergen, they release histamine and other chemicals, both locally and into the bloodstream. These chemicals cause blood vessels to become more porous, allowing fluid to accumulate in tissue and leading to the swollen and reddish appearance of hives. Some of the chemicals released sensitize pain-related nerve endings, causing the affected area to become itchy and sensitive.

A wide variety of substances may cause hives in sensitive people. Common culprits include:

• prescription and nonprescription drugs (Aspirin and penicillin are the two most commonly known causes of allergic reactions in adults.)
• nuts, especially peanuts, walnuts, and Brazil nuts
• fish, mollusks, and shellfish
• eggs
• wheat
• milk
• strawberries
• food additives and preservatives
• influenza vaccines
• tetanus toxoid vaccine
• gamma globulin
• bee, wasp, and hornet stings
• bites of mosquitoes, fleas, and scabies.

In addition, hives may also result from the body's response to certain physical conditions, such as emotional stress , rubbing, cold wind, heat contact (prickly heat rash), wearing tight clothing, or exercise after a heavy meal.

Symptoms

Urticaria is characterized by redness, swelling, and itching of small areas of the skin. These patches usually grow and recede in less than a day, but may be replaced by others in other locations. Angioedema is characterized by more diffuse swelling. Swelling of the airways may cause wheezing and respiratory distress. In severe cases, airway obstruction may occur.

Diagnosis

Hives are easily diagnosed by visual inspection. The cause of hives is usually apparent, but may require a careful medical history in some cases.

Treatment

Home remedies

To deal with the symptoms of hives, an oatmeal bath may help to relieve itching. Chickweed (Stellaria media ), applied as a poultice (crushed or chopped herbs applied directly to the skin) or added to bath water, may also help relieve itching.

Nutritional therapy

Naturopaths or nutritionists will try to determine what allergic substance is causing the reaction and help the patient eliminate or minimize its effects. They may also recommend vitamin C, vitamin B₁₂ , and quercetin (a flavonoid) supplements to help control acute or chronic hives.

Homeopathic therapy

The following homeopathic remedies have been used to relieve itching, redness or swelling associated with hives:

• Urtica urens
• Apis (Apis mellifica)
• Sulfur

Allopathic treatment

Mild cases of hives are treated with antihistamines, such as diphenhydramine (Benadryl). More severe cases may require such oral corticosteroids prednisone. Topical corticosteroids are not effective. In 2002, the Food and Drug Administration (FDA) approved the allergy drug Claritin for over-the-counter use for patients with urticaria. The drug comes in tablet and syrup form and carries little risk. Its release for over-the-counter use was delayed until the company that manufactures the drug could add instructions for patients about self-diagnosis of hives. They cautioned it should be used only for recurrent hives that had already been diagnosed by a physician, not for acute or severe urticaria. Airway swelling may require emergency injection of epinephrine (adrenaline).

Expected results

Most cases of hives clear up within one to seven days without treatment, provided the cause (allergen) is found and avoided.

Prevention

Preventing hives depends on avoiding the allergen causing them. Analysis of new items in the diet or new drugs taken may reveal the likely source of the reaction. Chronic hives may be aggravated by stress, caffeine , alcohol, or tobacco; avoiding these may reduce the frequency of reactions.

Resources

BOOKS

Jonas, Wayne B., and Jennifer Jacobs., "Skin Rashes." Healing with Homeopathy: The Doctor's Guide. New York, NY: Warner Books, 1996.

Lawlor, G. J., Jr., T.J. Fischer, and D.C. Adelman. Manual of Allergy and Immunology. Boston, MA: Little, Brown and Co., 1995.

Murray, Michael T. and Joseph E. Pizzorno. "Hives." Encyclopedia of Natural Medicine. Revised 2nd ed. Rocklin, CA: Prima Publishing, 1998.

Novick, N. L. You Can Do Something About Your Allergies. NY: Macmillan, 1994.

PERIODICALS

Franklin, Deanna. "FDA Panel Recommends OTC Approval of Claritin (Urticaria Indication Debated)." Family Practice News (June 15, 2002):26–31.

Mai Tran

Teresa G. Odle

Hives

Definition

Hives is an allergic skin reaction causing localized redness, swelling, and itching.

Description

Hives is a reaction of the body's immune system that causes areas on the surface of the skin to swell, itch, and become reddened (wheals). These lesions are elevated, can be blanched with pressure applied from a finger, and are oval in shape. When the reaction is limited to small areas of the skin, it is called urticaria. Involvement of larger areas, such as whole sections of a limb, is called angioedema.

Causes and symptoms

Causes

Hives is an allergic reaction. The body's immune system is normally responsible for protection from foreign invaders. When it becomes sensitized to normally harmless substances, the resulting reaction is called an allergy. An attack of hives is set off when such a substance, called an allergen, is ingested, inhaled, or otherwise contacted. It interacts with immune cells called mast cells, which reside in the skin, airways, and digestive system . When mast cells encounter an allergen, they release histamine and other chemicals, both locally and into the bloodstream. These chemicals cause blood vessels to become more porous, allowing fluid to accumulate in tissue and leading to the swollen and reddish appearance of hives. Some of the chemicals released sensitize pain-nerve endings, causing the affected area to become itchy (pruritic) and sensitive.

A wide variety of substances may cause hives in sensitive people, including food, drugs, insect or stings, and common household items. Common culprits include:

• nuts, especially peanuts, walnuts, and Brazil nuts
• fish, mollusks, and shellfish
• eggs
• wheat
• milk
• strawberries
• food additives and preservatives
• penicillin or other antibiotics
• flu vaccines
• tetanus toxoid vaccine

• gamma globulin
• bee, wasp, and hornet stings
• bites of mosquitoes, fleas, and scabies.
• dander from house pets
• new fragrances, laundry soaps, hand lotions, or articles of clothing
• certain plants, molds, chemicals, or dust particles

Symptoms

Urticaria is characterized by redness, swelling, and itching of small areas of the skin. These patches usually grow and recede in less than a day, but may recur in other locations, and complete resolution can take four to six weeks. Angioedema is characterized by more diffuse swelling. Swelling of the airways may cause wheezing and respiratory distress. In severe cases, airway obstruction may occur.

Diagnosis

Hives are easily diagnosed by visual inspection. The cause is usually more difficult to diagnose and requires a thorough medical history in order to determine the allergen.

Treatment

Mild cases of hives are treated with antihistamines , such as diphenhydramine (Benadryl). The major side effect of diphenhydramine is drowsiness. Newer antihistamines, such as loratadine (Claritin), are non sedating and are used more frequently with chronic hives management. More severe cases may require oral corticosteroids , such as prednisone. Prednisone helps block the release of mast cells and decreases the leakiness of blood vessel walls. Gradual tapering doses of prednisone are the most common way to take this medication. Topical corticosteroids are not effective. Airway swelling may require an emergency injection of epinephrine (adrenaline). Epinephrine constricts the blood vessels of the skin and immediately combats the histamine release.

An alternative practitioner will try to determine what allergic substance is causing the reaction and help the patient eliminate or minimize its effects. To deal with the symptoms of hives, an oatmeal bath may help to relieve itching. Chickweed (Stellaria media), applied as a poultice (crushed or chopped herbs applied directly to the skin) or added to bath water, may also help relieve itching. Several homeopathic remedies, including Urtica urens and Apis (Apis mellifica), may help relieve the itch, redness, or swelling associated with hives.

Prognosis

Most cases of hives clear up within one to seven days without treatment, providing the cause (allergen) is found and avoided. Some bouts of hives can persist up to six weeks and can be frustrating for the sufferer.

Health care team roles

The health care professional (R.N., L.P.N.) completing the history of a person presenting with hives should focus on specific information to determine the patient's allergen. Important information to include:

• Broad aspects about urticaria (when it started, how long and how often do episodes happen, where on the body do they usually appear, at what point do symptoms start to abate, and if there is a link with seasonal changes).
• Work and leisure activities (questions specific to possible exposure).
• Recent management of hives (previously prescribed medication, OTC medication or herbal supplements).
• Dietary review (a thorough review of the person's diet can help identify potential food substances that are common allergens).

KEY TERMS

Allergen —A substance capable of producing an immediate type of hypersensitivity or allergy.

Pruritic —Itchy.

Wheal —A smooth, slightly elevated area on the body surface, which is redder or paler than the surrounding skin.

Patient education

Patient education should focus on teaching the significance of avoiding allergens and the identification of the early signs of a hives outbreak. The patient should be made aware of the fact that diphenhydramine (Benadryl) causes sedation and should not be taken when driving or operating heavy machinery. If urticaria becomes a chronic problem, the patient should be made aware of the many new drugs that can help manage the condition.

Prevention

Preventing hives is only possible by avoiding the allergens causing them. Analysis of new items in the diet, new drugs taken, or new products at home may reveal the likely source of the allergen. Chronic hives can also be aggravated by stress , caffeine , alcohol, or tobacco; avoiding these may reduce the frequency of reactions. For people with chronic hives, referral to a doctor who specializes in allergies , skin disorders, immune disorders, or rheumatology may be helpful.

Resources

PERIODICALS

Pien, Lily, C. "Appropriate Use of Second-Generation Antihistamines." Cleveland Clinic Journal of Medicine 67(May 2000): 372-380.

Trotto, Nancy E. "Asthma, Rhinitis, Sinusitis, Urticaria." Patient Care Archive (January 15, 1999): 115-116, 118-119, 123-124.

OTHER

Crawford, M.B. "Urticaria from Emergency Medicine and Dermatology." eMedicine.com 2001. <http://www.emedicine.com/emerg/topics628.htm> (February 7, 2001).

Lory Beck

Hives

Definition

Hives is an allergic skin reaction causing localized redness, swelling, and itching.

Description

Hives is a reaction of the body's immune system that causes areas on the surface of the skin to swell, itch, and become reddened (wheals). These lesions are elevated, can be blanched with pressure applied from a finger, and are oval in shape. When the reaction is limited to small areas of the skin, it is called urticaria. Involvement of larger areas, such as whole sections of a limb, is called angioedema.

Causes and symptoms

Causes

Hives is an allergic reaction. The body's immune system is normally responsible for protection from foreign invaders. When it becomes sensitized to normally harmless substances, the resulting reaction is called an allergy. An attack of hives is set off when such a substance, called an allergen, is ingested, inhaled, or otherwise contacted. It interacts with immune cells called mast cells, which reside in the skin, airways, and digestive system. When mast cells encounter an allergen, they release histamine and other chemicals, both locally and into the bloodstream. These chemicals cause blood vessels to become more porous, allowing fluid to accumulate in tissue and leading to the swollen and reddish appearance of hives. Some of the chemicals released sensitize painnerve endings, causing the affected area to become itchy (pruritic) and sensitive.

A wide variety of substances may cause hives in sensitive people, including food, drugs, insect or stings, and common household items. Common culprits include:

• nuts, especially peanuts, walnuts, and Brazil nuts
• fish, mollusks, and shellfish
• eggs
• wheat
• milk
• strawberries
• food additives and preservatives
• penicillin or other antibiotics
• flu vaccines
• tetanus toxoid vaccine
• gamma globulin
• bee, wasp, and hornet stings
• bites of mosquitoes, fleas, and scabies
• dander from house pets
• new fragrances, laundry soaps, hand lotions, or articles of clothing
• certain plants, molds, chemicals, or dust particles

Symptoms

Urticaria is characterized by redness, swelling, and itching of small areas of the skin. These patches usually grow and recede in less than a day, but may recur in other locations, and complete resolution can take four to six weeks. Angioedema is characterized by more diffuse swelling. Swelling of the airways may cause wheezing and respiratory distress. In severe cases, airway obstruction may occur.

Diagnosis

Hives are easily diagnosed by visual inspection. The cause is usually more difficult to diagnose and requires a thorough medical history in order to determine the allergen.

Treatment

Mild cases of hives are treated with antihistamines, such as diphenhydramine (Benadryl). The major side effect of diphenhydramine is drowsiness. Newer antihistamines, such as loratadine (Claritin), are nonsedating and are used more frequently with chronic hives management. More severe cases may require oral corticosteroids, such as prednisone. Prednisone helps block the release of mast cells and decreases the leakiness of blood vessel walls. Gradual tapering doses of prednisone are the most common way to take this medication. Topical corticosteroids are not effective. Airway swelling may require an emergency injection of epinephrine (adrenaline). Epinephrine constricts the blood vessels of the skin and immediately combats the histamine release.

An alternative practitioner will try to determine what allergic substance is causing the reaction and help the patient eliminate or minimize its effects. To deal with the symptoms of hives, an oatmeal bath may help to relieve itching. Chickweed (Stellaria media), applied as a poultice (crushed or chopped herbs applied directly to the skin) or added to bath water, may also help relieve itching. Several homeopathic remedies, including Urtica urens and apis (Apis mellifica), may help relieve the itch, redness, or swelling associated with hives.

Prognosis

Most cases of hives clear up within one to seven days without treatment, providing the cause (allergen) is found and avoided. Some bouts of hives can persist up to six weeks and can be frustrating for the sufferer.

Health care team roles

The health care professional (R.N., L.P.N.) completing the history of a person presenting with hives should focus on specific information to determine the patient's allergen. Important information to include:

• Broad aspects about urticaria (when it started, how long and how often do episodes happen, where on the body do they usually appear, at what point do symptoms start to abate, and if there is a link with seasonal changes).
• Work and leisure activities (questions specific to possible exposure).
• Recent management of hives (previously prescribed medication, OTC medication or herbal supplements).
• Dietary review (a thorough review of the person's diet can help identify potential food substances that are common allergens).

Patient education

Patient education should focus on teaching the significance of avoiding allergens and the identification of the early signs of a hives outbreak. The patient should be made aware of the fact that diphenhydramine (Benadryl) causes sedation and should not be taken when driving or operating heavy machinery. If urticaria becomes a chronic problem, the patient should be made aware of the many new drugs that can help manage the condition.

Prevention

Preventing hives is only possible by avoiding the allergens causing them. Analysis of new items in the diet, new drugs taken, or new products at home may reveal the likely source of the allergen. Chronic hives can also be aggravated by stress, caffeine, alcohol, or tobacco; avoiding these may reduce the frequency of reactions. For people with chronic hives, referral to a doctor who specializes in allergies, skin disorders, immune disorders, or rheumatology may be helpful.

KEY TERMS

Allergen— A substance capable of producing an immediate type of hypersensitivity or allergy.

Pruritic— Itchy.

Wheal— A smooth, slightly elevated area on the body surface, which is redder or paler than the surrounding skin.

Resources

PERIODICALS

Pien, Lily C. "Appropriate Use of Second-Generation Antihistamines." Cleveland Clinic Journal of Medicine 67 (May 2000): 372-380.

Trotto, Nancy E. "Asthma, Rhinitis, Sinusitis, Urticaria." Patient Care Archive (January 15, 1999): 115-116, 118-119, 123-124.

OTHER

Crawford, M. B. "Urticaria from Emergency Medicine and Dermatology." eMedicine.com 2001. 〈http://www.emedicine.com/emerg/topics628.htm〉 (February 7, 2001).

Hives

Definition

Hives is an allergic skin reaction causing localized redness, swelling, and itching.

Description

Hives is a reaction of the body's immune system that causes areas of the skin to swell, itch, and become reddened (wheals). When the reaction is limited to small areas of the skin, it is called "urticaria." Involvement of larger areas, such as whole sections of a limb, is called "angioedema."

Causes and symptoms

Causes

Hives is an allergic reaction. The body's immune system is normally responsible for protection from foreign invaders. When it becomes sensitized to normally harmless substances, the resulting reaction is called an allergy. An attack of hives is set off when such a substance, called an allergen, is ingested, inhaled, or otherwise contacted. It interacts with immune cells called mast cells, which reside in the skin, airways, and digestive system. When mast cells encounter an allergen, they release histamine and other chemicals, both locally and into the bloodstream. These chemicals cause blood vessels to become more porous, allowing fluid to accumulate in tissue and leading to the swollen and reddish appearance of hives. Some of the chemicals released sensitize pain nerve endings, causing the affected area to become itchy and sensitive.

A wide variety of substances may cause hives in sensitive people, including foods, drugs, and insect bites or stings. Common culprits include:

• nuts, especially peanuts, walnuts, and Brazil nuts
• fish, mollusks, and shellfish
• eggs
• wheat
• milk
• strawberries
• food additives and preservatives
• penicillin or other antibiotics
• flu vaccines
• tetanus toxoid vaccine
• gamma globulin
• bee, wasp, and hornet stings
• bites of mosquitoes, fleas, and scabies

Symptoms

Urticaria is characterized by redness, swelling, and itching of small areas of the skin. These patches usually grow and recede in less than a day, but may be replaced by hives in other locations. Angioedema is characterized by more diffuse swelling. Swelling of the airways may cause wheezing and respiratory distress. In severe cases, airway obstruction may occur.

Diagnosis

Hives are easily diagnosed by visual inspection. The cause of hives is usually apparent, but may require a careful medical history in some cases.

Treatment

Mild cases of hives are treated with antihistamines, such as diphenhydramine (Benadryl) or desloratadine (Clarinex). Clarinex is non-sedating, meaning it will not make patients drowsy. More severe cases may require oral corticosteroids, such as prednisone. Topical corticosteroids are not effective. Airway swelling may require emergency injection of epinephrine (adrenaline).

Alternative treatment

An alternative practitioner will try to determine what allergic substance is causing the reaction and help the patient eliminate or minimize its effects. To deal with the symptoms of hives, an oatmeal bath may help to relieve itching. Chickweed (Stellaria media ), applied as a poultice (crushed or chopped herbs applied directly to the skin) or added to bath water, may also help relieve itching. Several homeopathic remedies, including Urtica urens and Apis (Apis mellifica), may help relieve the itch, redness, or swelling associated with hives.

Prognosis

Most cases of hives clear up within one to seven days without treatment, providing the cause (allergen) is found and avoided.

Prevention

Preventing hives depends on avoiding the allergen causing them. Analysis of new items in the diet or new drugs taken may reveal the likely source of the reaction. Chronic hives may be aggravated by stress, caffeine, alcohol, or tobacco; avoiding these may reduce the frequency of reactions.

KEY TERMS

Allergen— A substance capable of producing an immediate type of hypersensitivity, or allergy.

Wheal— A smooth, slightly elevated area on the body surface, which is redder or paler than the surrounding skin.

Resources

PERIODICALS

Kirn, F. Timothy. "Desloratadine Improves Urticaria in Clinical Setting." Skin & Allergy News September 2004: 41.