Histamines are chemicals your body produces in an attempt to defend itself against infection and other outside intruders. Unfortunately, in some people, the histamines can cause swelling, itching, and many of the symptoms that are experienced with hives. In terms of allergens, hives can be caused by factors such as pollen, medications, food, animal dander, and insect bites.
Hives might also be caused by circumstances besides allergies. As there are several potential triggers, many times the actual cause of hives cannot be determined. People who are known to have allergies are more likely to get hives. You may also be at risk to develop hives if you are on medication or if you are unknowingly exposed to things you may be allergic to, such as food or pollen.
If you are already ill with an infection or a health condition, you may be more vulnerable to developing hives. The most noticeable symptom associated with hives is the welts that appear on the skin. Welts may be red, but can also be the same color as your skin. They can be small and round, ring-shaped, or large and of random shape.
Hives are itchy, and they tend to appear in batches on the affected part of the body. They can grow larger, change shape, and spread. Hives may disappear or reappear over the course of the outbreak. Individual hives can last anywhere from half an hour to a day.
Hives may turn white when pressed. Sometimes the hives may change shape or form together and create a larger, raised area. Hives can occur in a variety of places on the body. Call or seek medical attention immediately if you develop a hive outbreak around your throat or on your tongue or have trouble breathing along with hives.
The most common causes of hives are allergic reactions. These can be caused by any allergen you might be sensitive to, including:. Mild cases of hives caused by allergies are typically treated with long- or short-term allergy medications and avoidance of the trigger.
Anaphylaxis is a severe, life-threatening allergic reaction. This content does not have an English version. This content does not have an Arabic version. Overview Hives on white skin Open pop-up dialog box Close.
Hives on white skin Hives may be accompanied by angioedema, which can cause swollen welts that appear reddish on white skin. Hives on brown skin Open pop-up dialog box Close. Hives on brown skin Hives, also known as urticaria, causes itchy welts that may be triggered by exposure to certain foods, medications or other substances. Angioedema Open pop-up dialog box Close.
Angioedema Angioedema may cause large welts below the surface of the skin, particularly around the eyes and lips. Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references Hives. American Academy of Dermatology. Accessed April 25, Nails may also thicken, ridge or become pitted. Affected skin areas may also affect the joints, causing swelling and stiffness. A person may be more prone to hives if they have existing food allergies, are under a fair amount of stress or have sensitive skin.
Those who experience flare-ups of psoriasis generally have a family history of the condition, experience chronic levels of intense stress, smoke, are overweight or who generally have a weak or compromised immune system.
April Sydney Children's Hospital Network. October Centers for Disease Control and Prevention. June What is Psoriasis? What do hives look and feel like? Choudhury says.
He says one way to tell the difference is by how quickly the welts clear up. Other skin issues that are often mistaken for hives tend to last for more than one day in the same location, he explains. Also, check out the welts up close. As mentioned, acute hives will usually disappear within 24 hours. It might seem like longer, though, because new hives may appear when old ones go away.
In total, you could be dealing with hives for six weeks. If you have chronic hives , however, the hives will last for longer than six weeks. Acute hives the ones that clear up within six weeks or less can be straightforward and may not require medical attention.
But sometimes hives do warrant a visit to the doctor — or the emergency room in severe cases. He or she will likely run a skin-prick test to identify possible triggers that are causing the breakout. Be on the lookout for more threatening symptoms, too.
0コメント