Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR
Hives are swollen, red or pink bumps, patches, or welts on the skin that usually appear suddenly. Itching is the most common symptom associated with hives, although some people report that hives cause a stinging or burning sensation. Hives are a very common reaction to all kinds of stimuli. While an allergic reaction can be a cause of hives, in the majority of outbreaks, the exact cause of hives is not known. Hives are also known as urticaria.
Hives form when a chemical called histamineis released by specialized cells known as mast cells. It is true that allergic reactionsultimately lead to the release of histamine, but other circumstances can result in the release of histamine, causing an outbreak of hives. Histamine acts by causing blood vessels to leak fluid into the nearby tissues. In the skin, small areas of swelling develop as a result of capillary (the smallest blood vessels) leakage.
In addition to allergic reactions to medications, foods, or other substances, hives may be triggered by direct physical stimulation such as temperature extremes, water, sun, and physical exercise. Having a viral infection can also cause an outbreak of hives, and even stressand nervousness have been associated with hives outbreaks. In the form of hives known as dermographia, or "skin writing," raised, itchy red welts with adjacent flares appear wherever the skin is scratched or where belts and other articles of clothing rub against the skin.
Hives (medically known as urticaria) are red, itchy, raised areas of skin that appear in varying shapes and sizes.
Hives are very common and most often their cause is elusive.
Hives can change size rapidly and to move around, disappearing in one place and reappearing in other places, often in a matter of hours.
Ordinary hives flare up suddenly.
Physical hives are hives produced by direct physical stimulation of the skin.
Treatment of hives is directed at symptom relief while the condition goes away on its own.
Antihistamines are the most common treatment for hives.
Hives typically are not associated with long-term or serious complications.
What are hives (urticaria) and angioedema?
Hives (medically known as urticaria) appear on the skin as wheals that are red, very itchy, smoothly elevated areas of skin often with a blanched center. They appear in varying shapes and sizes, from a few millimeters to several inches in diameter anywhere on the body.
It is estimated that 20% of all people will develop urticaria at some point in their lives. Hives are more common in women than in men. One hallmark of hives is their tendency to change size rapidly and to move around, disappearing in one place and reappearing in other places, often in a matter of hours. Individual hives usually last no longer than 24 hours. An outbreak that looks impressive, even alarming, first thing in the morning can be completely gone by noon, only to be back in full force later in the day. Very few, if any other skin diseases occur and then resolve so rapidly. Therefore, even if you have no evidence of hives to show the doctor when you get to the office for examination, the diagnosis can be established based upon the accurate accounting of your symptoms and signs. Because hives fluctuate so much and so fast, it is helpful to bring along a photograph of what the outbreak looked like at its worst.
Swelling deeper in the skin that may accompany hives is called angioedema.
This swelling of the hands and feet, as well as the lips or eyelids, can be as dramatic as it is brief.
What causes hives and angioedema?
Hives are produced when histamine and other compounds are released from cells called mast cells, which are normally found in the skin. Histamine causes fluid to leak from the local blood vessels, leading to swelling in the skin.
Hives are very common. Although they can be annoying, they usually resolve on their own over a period of weeks and are rarely medically serious. Some hives are caused by allergies to such things as foods, medications, and insect stings, but in the majority of cases, no specific cause for them is ever found. Although patients may find it frustrating not to know what has caused their hives, maneuvers like changing diet, soap, detergent, and makeup are rarely helpful in preventing hives unless there is an excellent temporal relationship.
Having hives may cause stress, but stress by itself does not cause hives.
When to visit the doctor
In rare cases (some hereditary, others caused by bee
stings or drug allergy),
urticaria and angioedema are accompanied by a striking decrease in blood pressure (shock) and difficulty
breathing. This is called anaphylaxis and may rapidly become a medical emergency. In this case, a visit to the emergency room or your doctor is necessary. Ordinary hives may be widespread and disturbing to look at, but the vast majority of cases of hives do not lead to life-threatening complications.
The word "rash" means an outbreak of red bumps on the body. The way people use this term, "a rash" can refer to many different skin conditions. The most common of these are scaly patches of skin and red, itchy bumps or patches all over the place.
Eczema, also known as dermatitis, is a general term for many types of skin inflammation. The most common form of eczema is atopic dermatitis. The other forms of eczema include: contact eczema, seborrheic eczema, Nummular eczema, Neurodermatitis, stasis dermatitis, and dyshidrotic eczema. Symptoms, diagnosis, and treatment of eczema may vary from person to person and may depend on the type of eczema.
Itching can be a common problem. Itches can be localized or generalized. There are many causes of itching to include: infection (jock itch, vaginal itch), disease (hyperthyroidism, liver or kidney), reactions to drugs, and skin infestations (pubic or body lice). Treatment for itching varies depending on the cause of the itch.
An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. When these allergens come in contact with the body, it causes the immune system to develop an allergic reaction in people who are allergic to it. It is estimated that 50 million North Americans are affected by allergic conditions. The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Common allergic disorders include hay fever, asthma, allergic eyes, allergic eczema, hives, and allergic shock.
Eczema is a general term for many types dermatitis (skin inflammation). Atopic dermatitis is the most common of the many types of eczema. Other types of eczema include: contact eczema, allergic contact eczema, seborrheic eczema, nummular eczema, stasis dermatitis, and. dyshidrotic eczema.
The most common food allergies are to eggs, nuts, milk, peanuts, fish, shellfish, strawberries and tomatoes. Symptoms and signs include nausea, vomiting, diarrhea, abdominal pain, itching, hives, eczema, asthma, lightheadedness, and anaphylaxis. Allergy skin tests, RAST, and ELISA tests may be used to diagnose a food allergy. Though dietary avoidance may be sufficient treatment for mild allergies, the use of an Epipen may be necessary for severe food allergies.
Anaphylaxis is a serious allergic reaction that affects a number of different areas of the body at one time, and can be fatal. Causes of anaphylaxis can be food allergy, latex allergy, allergy to insect or but stings/bites, asthma, or other materials or conditions. Symptoms include flushing, itching, hives, anxiety, rapid or irregular pulse. Severe symptoms may be throat and tongue swelling, swallowing, and difficulty breathing. Some disorders appear similar to anaphylaxis such as fainting, panic attacks, blood clots in the lungs, heart attacks, and septic shock. If you think that you may be having an anaphylactic reaction, seek emergency care or call 911 immedately.
Bug bites and stings have been known to transmit insect-borne illnesses such as West Nile virus, Rocky Mountain spotted fever, and Lyme disease. Though most reactions to insect bites and stings are mild, some reactions may be life-threatening. Preventing bug bites and stings with insect repellant, wearing the proper protective attire, and not wearing heavily scented perfumes when in grassy, wooded, and brushy areas is key.
The most common cause of a black eye is due to an injury to the face or head. Most black eye injuries are minor and heal on their own, however, some may lead to significant injury. In addition to trauma to the face, cosmetic surgery can cause a black eye(s) as a side effect. People should be aware of the situations in which medical care should be sought immediately for a black eye.
Drug allergies are cause when the immune system mistakenly creates an immune response to a medication. Symptoms of a drug allergic reaction include hives, rash, itchy skin or eyes, dizziness, nausea, diarrhea, fainting and anxiety. The most common drug allergy is penicillin. Treatment may involve antihistamines or corticosteroids. An Epipen may be used for life-threatening anaphylactic symptoms.
Infections, bites and stings, infestations, chronic diseases, sun exposure, and dry skin are among the numerous causes of itching.
Anti-itch creams and lotions containing camphor, menthol, phenol,
pramoxine (Caladryl, Tronolane), diphenhydramine (Benadryl), or benzocaine can bring relief.
Some cases of itching will respond to corticosteroid medications.
It is best to avoid scratching and itch when possible to avoid worsening of the condition and disruption of the skin that could lead to bacterial infection.
If itching persists with time or worsens, or is associated with skin lesions, consulting a health-care practitioner is advisable.
What is an itch?
Itch is an irritation in the skin that elicits an urge to scratch. Itches are a common problem and can be localized (limited to one area of the bo...
