Severe allergic reactions anaphylaxis and asthma attacks need urgent emergency first aid. In an emergency, always call triple zero Allergy occurs when the body overreacts to a 'trigger' that is harmless to most people.
Allergies to insect stings and bites range from milder allergic reactions to life-threatening, severe allergic reactions anaphylaxis. All medication has the potential to cause allergies but some people can have allergic reactions to specific prescription or over-the-counter medications. Allergy testing is used to find which substances provoke an allergic reaction. Content on this website is provided for information purposes only.
Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances.
The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website. Skip to main content. Home Allergies. Actions for this page Listen Print.
Summary Read the full fact sheet. On this page. Mast cells and histamines Symptoms of hives Causes of hives Treatment for hives Where to get help. Mast cells and histamines Underneath the lining of the skin, gut, lungs, nose and eyes are mast cells. Occasionally, hives produce swelling without an itch. Symptoms of hives Symptoms of hives include: raised circular weals that look like mosquito bites — these are red on the outer rim and white in the centre, and each weal lasts for around two to four hours rarely up to 24 hours.
Weals appear in batches or clusters, and as one batch fades away as a new batch appears localised itching with acute urticaria, the rash may last for days or weeks with chronic hives, the rash may persist for months to years, occasionally decades.
Hives Hives, also known as urticaria, affects about 20 percent of people at some time during their lives. On this page. Whether your allergist suggests a treatment available only by prescription or an over the counter treatment will depend on several factors, including how uncomfortable the hives are making you.
Find expert care. Find an Allergist. Symptoms Symptoms can last anywhere from minutes to months — or even years. While they resemble bug bites, hives also known as urticaria are different in several ways: Hives can appear on any area of the body; they may change shape, move around, disappear and reappear over short periods of time. Allergist Stanley Fineman, MD. Is It Hives or Angioedema? The following symptoms may indicate angioedema: Swelling in the eyes or mouth Swelling of the hands, feet or throat Difficulty breathing, stomach cramps or swelling of the lining of the eyes The best way to identify your symptoms is to talk to an allergist who can diagnose and treat both hives and angioedema.
Diagnosis In some cases, the trigger is obvious — a person eats peanuts or shrimp , and then breaks out within a short time. Management and Treatment Researchers have identified many — but not all — of the factors that can cause hives. Here are a few of the most common causes: Some food especially peanuts, eggs, nuts and shellfish Medications, such as antibiotics especially penicillin and sulfa , aspirin and ibuprofen Insect stings or bites Physical stimuli such as pressure, cold, heat, exercise or sun exposure Latex Blood transfusions Bacterial infections, including urinary tract infections and strep throat Viral infections, including the common cold, infectious mononucleosis and hepatitis Pet dander Pollen Some plants Antihistamines — available either over the counter or by prescription — are a frequently recommended treatment for hives.
Rubbing or scratching: Avoid harsh soaps. Frequent baths may reduce itching and scratching — beneficial because itching and scratching can make the hives feel worse. Constant pressure: Avoid tight clothing.
Pressure hives can be relieved by wearing loose-fitting clothes. Temperature: If you develop hives when exposed to cold, do not swim alone in cold water and always carry an epinephrine auto-injector.
Avoid exposure to cold air and use a scarf around your nose and mouth in cold weather. If you must be out in the cold, wear warm clothing.
Sun exposure: Wear protective clothing; apply sunblock. Medications: Notify your physician or pharmacist immediately if you suspect that a specific medication is causing your hives. Chronic hives Some cases of hives last for more than six weeks and can last months or years. Physical urticaria In physical urticaria, the hives have a physical cause, such as exposure to heat, cold or pressure.
Common triggers include: Rubbing or scratching. This is the most frequent cause of physical urticaria. Symptoms appear within a few minutes in the place that was rubbed or scratched and typically last less than an hour.
Pressure or constriction. Delayed pressure urticaria can appear as red swelling six to eight hours after pressure belts or constrictive clothing, for example has been applied.
Symptoms can also occur in parts of the body under constant pressure, such as the soles of the feet. Change in temperature. Cold urticaria is caused by exposure to low temperatures followed by re-warming. This can be severe and life-threatening if there is a general body cooling — for example, after a plunge into a swimming pool. Higher body temperature. Sun exposure. Solar urticaria may occur within a few minutes after exposure to the sun.
Submit site search Need An Allergist? Most individual hives last no more than 24 hours. Acute episodes of urticaria last for six weeks or less. Acute urticaria can be due to infections foods, medications, insect stings, blood transfusions and infections.
The most common cause of hives is infections. Foods such as eggs, nuts and shellfish are common causes of urticaria. Medications such as aspirin and antibiotics especially penicillin and sulfa also are common causes of hives.
Infections causing hives include the common cold, and other viral infections. In most of these cases, when the reason for hives is removed or avoided, the hives resolve. Chronic episodes of urticaria last more than six weeks. In most cases, the cause of chronic hives will not be identified despite testing.
Half of the patients have antibodies proteins that attack the mast cell allergy cell. This triggers chemicals such as histamine to be released which causes the hives and itching. Rarely, chronic urticaria has been associated with cancer. In most cases of chronic urticaria, the hives will gradually disappear over time. Physical urticaria is due to one or more "physical" causes. The most common reason for long-lasting hives is dermographism. These hives appear within a few minutes of scratching along an area of skin.
0コメント