hives

What is Hives?


Urticaria is thought to be activated by a trigger that causes a release of histamine and other chemicals from under the skin's surface. This causes inflammation and fluid to gather under the skin, causing wheals and the blood vessels to dilate. The trigger is unknown in approximately half of the cases of acute urticaria.

Read more on www.nhs.uk
Also known as Urticaria, Urticarias
Search for any health
topic on HealthMash:

Explore and Discover

Drugs and Substances
» zyrtec
» pepcid
Alternative Medicine

Hives information from trusted sources:

Urticaria

Hives are red and sometimes itchy bumps on your skin. An allergic reaction to a drug or food usually causes them. Allergic reactions cause your body to release chemicals that can make your skin swell up in hives. People who have other allergies are more likely to get hives than other people. Other causes include infections and stress. Hives are very common. They usually go away on their own, but if you have a serious case, you might need medicine or a shot. In rare cases, allergic reactions can cause a dangerous swelling in your airways, making it hard to breathe - which is a medical emergency.

Read more on www.nlm.nih.gov

Hives

Hives are raised, often itchy, red welts on the surface of the skin. They are usually an allergic reaction to food or medicine.

Read more on www.nlm.nih.gov

Urticaria

Nettle rash (also known as urticaria, hives or welts) is a raised, red, itchy rash that appears on the skin. Urticaria happens when a trigger, normally an allergen (something that produces an allergic reaction) causes the body to release histamine, a protein in our body. Histamine causes tiny blood vessels, known as capillaries, to leak fluid. The fluid then gathers in our skin and causes a rash.

Read more on www.nhs.uk

Urticaria

Hives (urticaria), also known as welts, is a common skin condition with an itchy rash of pink to red bumps that appear and disappear anywhere on the body. An individual lesion of hives typically lasts a few hours before fading away, and new hives can appear as older areas disappear.

Read more on www.visualdxhealth.com

Chronic hives

Chronic hives, also known as urticaria, are batches of raised, red or white itchy welts (wheals) of various sizes that appear and disappear. While most cases of hives go away within a few weeks or less, for some people they are a long-term problem. Chronic hives are defined as hives that last more than six weeks or hives that go away, but recur frequently.

Read more on www.mayoclinic.com

Hives and Angioedema

Hives is an allergic skin reaction that comes on suddenly. The hives themselves are slightly raised, smooth, flat-topped bumps called wheals (look like mosquito bites) and welts that are usually more red in color than the surrounding skin and cause severe itching. Angioedema is like hives, only the welts are larger and form at a deeper layer in the skin. This causes severe swelling, usually in the face, near the eyes and mouth. The swelling can also occur in the inside of the throat, which is a dangerous situation because it can close off the passage of air into the lungs.

Contents

Complications
Around 25% of people with acute urticaria will also develop acute angioedema at the same time. Acute angioedema will normally resolve within 3 days. However, you should dial 999 if you start having difficulties breathing.

Read more on www.nhs.uk
Diagnosis
Acute urticaria can usually be successfully diagnosed by examining the rash on your skin. Your GP will also want to find out what triggered the urticaria, so you can avoid it in future.

Read more on www.nhs.uk
Exams and Tests
Your doctor can tell if you have hives by looking at your skin.

Read more on www.nlm.nih.gov
Medical advice
Call 911 or your local emergency number if you have:Fainting; Shortness of breath; Tightness in your throat; Tongue or face swelling; Wheezing

Read more on www.nlm.nih.gov
Outlook (Prognosis)
Hives may be uncomfortable, but they generally are harmless and disappear on their own. In most cases, the exact cause of hives cannot be identified.

Read more on www.nlm.nih.gov
Possible Complications
Anaphylaxis (a life-threatening, whole-body allergic reaction that causes breathing difficulty); Swelling in the throat can lead to life-threatening airway blockage

Read more on www.nlm.nih.gov
Prevention
Avoid exposure to substances that give you allergic reactions.; Don't wear tight-fitting clothing and avoid hot baths or showers just after an episode of hives. These can both cause the hives to return.

Read more on www.nlm.nih.gov
Symptoms
The welts may get bigger, spread, and join together to form larger areas of flat, raised skin.

Read more on www.nlm.nih.gov
Treatment
Treatment may not be needed if the hives are mild. They may disappear on their own. To reduce itching and swelling: Avoid hot baths or showers, Avoid irritating the area with tight-fitting clothing, Take antihistamines. Diphenhydramine is considered the most effective. If your reaction is severe, especially if the swelling involves your throat, you may require an emergency shot of epinephrine (adrenaline) or steroids. Hives in the throat can block your airway, making it difficult to breathe.

Read more on www.nlm.nih.gov