2
4
5
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Hives (urticaria) on the back and buttocks
Hives (urticaria) on the back and buttocks
Hives (urticaria) on the back
Hives (urticaria) on the back
Hives (urticaria) on the chest
Hives (urticaria) on the chest

Hives
Definition:
Hives are raised red welts of various size on the surface of the skin, often itchy, which come and go.

Alternative Names:
Urticaria

Causes, incidence, and risk factors:
Hives are very common, especially in people who have experienced other allergic reactions, including hay fever and angioedema. The welts occur on the surface of the skin, usually in batches. Release of histamine and other chemicals into the bloodstream, associated with the allergic response, causes the itching, localized swelling, and other symptoms.

Many substances, called allergens, can trigger an allergic response resulting in hives. Common allergens include:
  • Medications
  • Foods (such as berries, shellfish, fish, nuts, eggs, milk, and others)
  • Pollen
  • Animal dander (especially cats)
  • Insect bites
Hives may also develop after infections or illness (including autoimmune diseases, leukemia, and others). There seems to be a hereditary tendency toward the development of hives.

Some less common causes of hives include:
Symptoms:
  • Itching (pruritus)
  • Swelling of the surface of the skin into red or skin colored welts (wheals) with clearly defined edges
    • Sudden onset
    • Rapid resolution
    • Welts blanch to touch
  • Welts enlarge, spread, or join together to form large flat raised areas
  • Welts change shape, disappear and reappear within minutes or hours
Signs and tests:
The diagnosis is primarily based on the appearance of the skin, and is confirmed by a history of exposure to an allergen. Occasionally, skin or blood tests may be performed.
Treatment:

Hives in the throat may obstruct the airway, so any swelling in the throat or difficulty breathing with hives are emergency symptoms. Call your local emergency medical services or visit the emergency room immediately.

Treatment may not be needed if hives are mild, and they may disappear spontaneously.

Antihistamines, adrenaline (epinephrine), corticosteroids (prednisone), sedatives, or tranquilizers may reduce the inflammation, itching, and swelling.

Self care:
Cool compresses or soaks to the area may reduce swelling and pain. Avoid irritation of the area, and don't wear tight clothing (which may trigger a new outbreak). Avoid known allergens to prevent recurrence of hives.
Expectations (prognosis):
Hives may be uncomfortable, but they generally are harmless and disappear on their own. In most cases, the exact cause of hives can not be identified.
Complications:
Calling your health care provider:
Call your health care provider if urticaria is severe and does not respond to treatment.

Call your health care provider or go to the emergency room if there is difficulty breathing, severe wheezing, or if fainting occurs.
Prevention:
  • Avoid exposure to substances that are a known allergen for you.
  • Take only prescribed medications.
  • Avoid hot baths or showers after an episode of urticaria to prevent recurrence.
Review Date: 10/28/2001
Reviewed By: Michael Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2003 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
adam.com