BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuHivesUrticaria - hives; WhealsHives are raised, usually itchy, red bumps (welts) on the surface of the skin. They can be an allergic reaction to food or medicine. They can also appear without cause.Related video goes here for no-HTML5 browsers Causes When you have an allergic reaction to a substance, your body releases histamine and other chemicals into the blood. This causes itching, swelling, and other symptoms. Hives are a common reaction. People with other allergies, such as hay fever, often get hives.Angioedema is swelling of the deeper tissue that sometimes occurs with hives. Like hives, angioedema can occur on any part of the body. When it occurs around the mouth or throat, the symptoms can be severe, including airway blockage.AngioedemaAngioedema is swelling that is similar to hives, but the swelling is under the skin instead of on the surface. Hives are often called welts. They a...ImageRead Article Now Book Mark Article Many substances can trigger hives, including:Animal dander (especially cats) Insect bites Medicines Pollen Shellfish, fish, nuts, eggs, milk, and other foods Hives may also develop as a result of:Emotional stress Extreme cold or sun exposure Excessive perspiration Illness, including lupus, other autoimmune diseases, and leukemia LupusSystemic lupus erythematosus (SLE) is an autoimmune disease. In this disease, the immune system of the body mistakenly attacks healthy tissue. It c...ImageRead Article Now Book Mark Article Autoimmune diseasesAn autoimmune disorder occurs when the body's immune system attacks and destroys healthy body tissue by mistake. There are more than 80 autoimmune d...ImageRead Article Now Book Mark Article LeukemiaLeukemia is a type of blood cancer that begins in the bone marrow. Bone marrow is the soft tissue in the center of the bones, where blood cells are ...ImageRead Article Now Book Mark Article Infections such as mononucleosis MononucleosisMononucleosis, or mono, is a viral infection that causes fever, sore throat, and swollen lymph glands, most often in the neck.ImageRead Article Now Book Mark Article Exercise Exposure to water Often, the cause of hives is not known. Symptoms Symptoms of hives may include any of the following:Itching. Swelling of the surface of the skin into red- or skin-colored welts (called wheals) with clearly defined edges. Wheals may get bigger, spread, and join together to form larger areas of flat, raised skin. Wheals often change shape, disappear, and reappear within minutes or hours. It is unusual for a wheal to last more than 48 hours. Dermatographism, or skin writing, is a type of hives. It is caused by pressure on the skin and results in immediate hives in the area that has been pressed on or scratched. Previous imagePlay SlideshowStop SlideshowNext image / Exams and Tests Your health care provider can tell if you have hives by looking at your skin.Previous imagePlay SlideshowStop SlideshowNext image / If you have a history of an allergy causing hives, for example, to strawberries, the diagnosis is even clearer.Sometimes, a skin biopsy or blood tests are done to confirm that you had an allergic reaction, and to test for the substance that caused the allergic response. However, specific allergy testing is not useful in most cases of hives.Skin biopsyA skin lesion biopsy is when a small amount of skin is removed so it can be examined under a microscope. The skin is tested to look for skin conditi...ImageRead Article Now Book Mark Article Treatment Treatment may not be needed if the hives are mild. They may disappear on their own. To reduce itching and swelling:Do not take hot baths or showers. Do not wear tight-fitting clothing, which can irritate the area. Your provider may suggest that you take an antihistamine such as diphenhydramine (Benadryl) or cetirizine (Zyrtec Allergy). Follow your provider's instructions or the package instructions about how to take the medicine. Other oral prescription medicines may be needed, especially if the hives are chronic (long-lasting). If your reaction is severe, especially if the swelling involves your throat, you may need an emergency shot of epinephrine (adrenaline) or steroids. Hives in the throat can block your airway, making it difficult to breathe. Outlook (Prognosis) Hives may be uncomfortable, but they are usually harmless and disappear on their own.When the condition lasts longer than 6 weeks, it is called chronic hives. Usually no cause can be found. Most chronic hives resolve on their own in less than 1 year. Possible Complications Complications of hives may include:Anaphylaxis (a life-threatening, whole-body allergic reaction that causes breathing difficulty) AnaphylaxisAnaphylaxis is a life-threatening type of allergic reaction.ImageRead Article Now Book Mark Article Swelling in the throat can lead to life-threatening airway blockage When to Contact a Medical Professional Call 911 or the local emergency number if you have:Fainting Shortness of breath Tightness in your throat Tongue or face swelling WheezingContact your provider if the hives are severe, uncomfortable, and do not respond to self-care measures. Prevention To help prevent hives, avoid exposure to substances that give you allergic reactions.Open ReferencesReferencesDinulos JGH. Urticaria, angioedema, and pruritus. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 6.James WD. Erythema and urticaria. In: James WD, ed. Andrews' Diseases of the Skin: Clinical Dermatology. 14th ed. Philadelphia, PA: Elsevier; 2026:chap 7.Saini SS. Urticaria and angioedema. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 232.AllVideoImagesTogHives (urticaria) - close-up - illustration Hives develop when histamine is released into the small blood vessels (capillaries). The capillaries dilate which causes a welt, and fluid oozes into the surrounding tissue, causing swelling. Histamine also causes intense itching.Hives (urticaria) - close-upillustrationFood allergies - illustration The body's immune system normally reacts to the presence of toxins, bacteria or viruses by producing a chemical reaction to fight these invaders. However, sometimes the immune system reacts to ordinarily benign substances such as food or pollen, to which it has become sensitive. This overreaction can cause symptoms from the mild (hives) to the severe (anaphylactic shock) upon subsequent exposure to the substance. An actual food allergy, as opposed to simple intolerance due to the lack of digesting enzymes, is indicated by the production of antibodies to the food allergen, and by the release of histamines and other chemicals into the blood.Food allergiesillustrationHives (urticaria) on the chest - illustration Hives (urticaria) are raised, red, itchy welts, seen here on the chest. The majority of urticaria develop as a result of allergic reactions. Occasionally they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.Hives (urticaria) on the chestillustrationHives (urticaria) on the trunk - illustration This person has raised, red, itchy welts (urticaria) on the chest and abdomen. The majority of urticaria develop as a result of allergic reactions. Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.Hives (urticaria) on the trunkillustrationHives (urticaria) on the chest - illustration The hives (urticaria) on this person's chest have the typical slightly-raised red appearance and are accompanied by itching. Hives can be generalized over the entire body or may be localized.Hives (urticaria) on the chestillustrationHives (urticaria) on the back and buttocks - illustration These are hives (urticaria) with the typical slightly-raised red appearance, and are accompanied by itching. These are located on the buttocks. Hives can be generalized over the entire body or may be localized, and usually result from an allergic reaction.Hives (urticaria) on the back and buttocksillustrationHives (urticaria) on the back - illustration The hives (urticaria) on this person's back have the typical slightly-raised red appearance and are accompanied by itching. Hives can generalized over the entire body, or may be localized.Hives (urticaria) on the backillustrationHives - illustration Hives are raised red welts of various size on the surface of the skin, often itchy, which come and go. Also called uticaria, hives is usually part of an allergic reaction to drugs or food. The term dermatitis describes an inflammatory response of the skin, caused by contact with allergens or irritants, exposure to sunlight, or by poor circulation, even stress. AVOID SCRATCHING. Scratching the rash may spread the inflammation, lead to infection and even leave scars.HivesillustrationHives treatment - illustration When there is an allergic reaction in the body, a chemical called histamine, from specialized cells in the body tissues is released. Histamine causes allergy symptoms such as sneezing, itching, watery eyes, and runny nose. Antihistamines may reduce inflammation, itching, and swelling by blocking the effects of histamine, reducing the allergy symptoms.Hives treatmentillustrationHives (urticaria) - close-up - illustration Hives develop when histamine is released into the small blood vessels (capillaries). The capillaries dilate which causes a welt, and fluid oozes into the surrounding tissue, causing swelling. Histamine also causes intense itching.Hives (urticaria) - close-upillustrationFood allergies - illustration The body's immune system normally reacts to the presence of toxins, bacteria or viruses by producing a chemical reaction to fight these invaders. However, sometimes the immune system reacts to ordinarily benign substances such as food or pollen, to which it has become sensitive. This overreaction can cause symptoms from the mild (hives) to the severe (anaphylactic shock) upon subsequent exposure to the substance. An actual food allergy, as opposed to simple intolerance due to the lack of digesting enzymes, is indicated by the production of antibodies to the food allergen, and by the release of histamines and other chemicals into the blood.Food allergiesillustrationHives (urticaria) on the chest - illustration Hives (urticaria) are raised, red, itchy welts, seen here on the chest. The majority of urticaria develop as a result of allergic reactions. Occasionally they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.Hives (urticaria) on the chestillustrationHives (urticaria) on the trunk - illustration This person has raised, red, itchy welts (urticaria) on the chest and abdomen. The majority of urticaria develop as a result of allergic reactions. Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.Hives (urticaria) on the trunkillustrationHives (urticaria) on the chest - illustration The hives (urticaria) on this person's chest have the typical slightly-raised red appearance and are accompanied by itching. Hives can be generalized over the entire body or may be localized.Hives (urticaria) on the chestillustrationHives (urticaria) on the back and buttocks - illustration These are hives (urticaria) with the typical slightly-raised red appearance, and are accompanied by itching. These are located on the buttocks. Hives can be generalized over the entire body or may be localized, and usually result from an allergic reaction.Hives (urticaria) on the back and buttocksillustrationHives (urticaria) on the back - illustration The hives (urticaria) on this person's back have the typical slightly-raised red appearance and are accompanied by itching. Hives can generalized over the entire body, or may be localized.Hives (urticaria) on the backillustrationHives - illustration Hives are raised red welts of various size on the surface of the skin, often itchy, which come and go. Also called uticaria, hives is usually part of an allergic reaction to drugs or food. The term dermatitis describes an inflammatory response of the skin, caused by contact with allergens or irritants, exposure to sunlight, or by poor circulation, even stress. AVOID SCRATCHING. Scratching the rash may spread the inflammation, lead to infection and even leave scars.HivesillustrationHives treatment - illustration When there is an allergic reaction in the body, a chemical called histamine, from specialized cells in the body tissues is released. Histamine causes allergy symptoms such as sneezing, itching, watery eyes, and runny nose. Antihistamines may reduce inflammation, itching, and swelling by blocking the effects of histamine, reducing the allergy symptoms.Hives treatmentillustrationRelated Information Angioedema(Condition)Mononucleosis(Condition)Autoimmune disorders(Condition)Anaphylaxis(Condition) Review Date: 4/1/2025 Reviewed By: Elika Hoss, MD, Assistant Professor of Dermatology, Mayo Clinic, Scottsdale, AZ. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. © 1997- All rights reserved. A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.Content is best viewed in IE9 or above, Firefox and Google Chrome browser.
HivesUrticaria - hives; WhealsHives are raised, usually itchy, red bumps (welts) on the surface of the skin. They can be an allergic reaction to food or medicine. They can also appear without cause.Related video goes here for no-HTML5 browsers Causes When you have an allergic reaction to a substance, your body releases histamine and other chemicals into the blood. This causes itching, swelling, and other symptoms. Hives are a common reaction. People with other allergies, such as hay fever, often get hives.Angioedema is swelling of the deeper tissue that sometimes occurs with hives. Like hives, angioedema can occur on any part of the body. When it occurs around the mouth or throat, the symptoms can be severe, including airway blockage.AngioedemaAngioedema is swelling that is similar to hives, but the swelling is under the skin instead of on the surface. Hives are often called welts. They a...ImageRead Article Now Book Mark Article Many substances can trigger hives, including:Animal dander (especially cats) Insect bites Medicines Pollen Shellfish, fish, nuts, eggs, milk, and other foods Hives may also develop as a result of:Emotional stress Extreme cold or sun exposure Excessive perspiration Illness, including lupus, other autoimmune diseases, and leukemia LupusSystemic lupus erythematosus (SLE) is an autoimmune disease. In this disease, the immune system of the body mistakenly attacks healthy tissue. It c...ImageRead Article Now Book Mark Article Autoimmune diseasesAn autoimmune disorder occurs when the body's immune system attacks and destroys healthy body tissue by mistake. There are more than 80 autoimmune d...ImageRead Article Now Book Mark Article LeukemiaLeukemia is a type of blood cancer that begins in the bone marrow. Bone marrow is the soft tissue in the center of the bones, where blood cells are ...ImageRead Article Now Book Mark Article Infections such as mononucleosis MononucleosisMononucleosis, or mono, is a viral infection that causes fever, sore throat, and swollen lymph glands, most often in the neck.ImageRead Article Now Book Mark Article Exercise Exposure to water Often, the cause of hives is not known. Symptoms Symptoms of hives may include any of the following:Itching. Swelling of the surface of the skin into red- or skin-colored welts (called wheals) with clearly defined edges. Wheals may get bigger, spread, and join together to form larger areas of flat, raised skin. Wheals often change shape, disappear, and reappear within minutes or hours. It is unusual for a wheal to last more than 48 hours. Dermatographism, or skin writing, is a type of hives. It is caused by pressure on the skin and results in immediate hives in the area that has been pressed on or scratched. Previous imagePlay SlideshowStop SlideshowNext image / Exams and Tests Your health care provider can tell if you have hives by looking at your skin.Previous imagePlay SlideshowStop SlideshowNext image / If you have a history of an allergy causing hives, for example, to strawberries, the diagnosis is even clearer.Sometimes, a skin biopsy or blood tests are done to confirm that you had an allergic reaction, and to test for the substance that caused the allergic response. However, specific allergy testing is not useful in most cases of hives.Skin biopsyA skin lesion biopsy is when a small amount of skin is removed so it can be examined under a microscope. The skin is tested to look for skin conditi...ImageRead Article Now Book Mark Article Treatment Treatment may not be needed if the hives are mild. They may disappear on their own. To reduce itching and swelling:Do not take hot baths or showers. Do not wear tight-fitting clothing, which can irritate the area. Your provider may suggest that you take an antihistamine such as diphenhydramine (Benadryl) or cetirizine (Zyrtec Allergy). Follow your provider's instructions or the package instructions about how to take the medicine. Other oral prescription medicines may be needed, especially if the hives are chronic (long-lasting). If your reaction is severe, especially if the swelling involves your throat, you may need an emergency shot of epinephrine (adrenaline) or steroids. Hives in the throat can block your airway, making it difficult to breathe. Outlook (Prognosis) Hives may be uncomfortable, but they are usually harmless and disappear on their own.When the condition lasts longer than 6 weeks, it is called chronic hives. Usually no cause can be found. Most chronic hives resolve on their own in less than 1 year. Possible Complications Complications of hives may include:Anaphylaxis (a life-threatening, whole-body allergic reaction that causes breathing difficulty) AnaphylaxisAnaphylaxis is a life-threatening type of allergic reaction.ImageRead Article Now Book Mark Article Swelling in the throat can lead to life-threatening airway blockage When to Contact a Medical Professional Call 911 or the local emergency number if you have:Fainting Shortness of breath Tightness in your throat Tongue or face swelling WheezingContact your provider if the hives are severe, uncomfortable, and do not respond to self-care measures. Prevention To help prevent hives, avoid exposure to substances that give you allergic reactions.Open ReferencesReferencesDinulos JGH. Urticaria, angioedema, and pruritus. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 6.James WD. Erythema and urticaria. In: James WD, ed. Andrews' Diseases of the Skin: Clinical Dermatology. 14th ed. Philadelphia, PA: Elsevier; 2026:chap 7.Saini SS. Urticaria and angioedema. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 232.
