Hives are small, itchy, red swellings on the skin. The swelling occurs singularly or in clusters. Hives tend to fade after a few hours, but new ones can appear. Most cases go away within a few days. But, some last a few weeks or longer.
Hives are often caused when the body releases a chemical called histamine. Histamine is released during an allergic reaction. Many people, though, get hives without being exposed to something they are allergic to.
While the cause is unknown in some cases, these factors may cause hives:
, most commonly:
- Fresh berries
- Reaction to ]]>allergy shots]]> (desensitization shots)
- ]]>Insect bites or stings]]>
- Cold or heat
- Thyroid disease ( ]]>hypothyroidism]]> , ]]>hyperthyroidism]]> )
- Vasculitis (inflammation of the blood vessels)
A risk factor is something that increases your chance of getting hives. Tell your doctor if you have any of these:
- Exposure to an allergen (something that causes an allergic reaction)
- Exposure to an allergen that triggered hives in the past
Symptoms of hives can vary from mild to severe:
- Excessive swelling of the eyelids, lips, or genitals
- Difficulty breathing or swallowing—Call 911 if you are having these symptoms
The doctor will ask about your symptoms and medical history, and perform a physical exam. You may need to see a doctor who specializes in skin disorders (dermatologist) or allergies (allergist). The following tests will be done:
- Skin prick test]]> —a tiny bit of an allergen is placed in your skin with a needle to see if the area becomes raised or irritated
- ]]>Skin biopsy]]> —a small portion of abnormal skin is removed
- ]]>X-ray]]> —a test that uses radiation to take a picture of structures inside the body, especially bones
- Blood tests
The best way to treat hives is to find and then avoid the cause.
If the cause can't be found, there are medications to treat hives:
- Diphenhydramine]]> (eg, Aler-Cap, Benadryl Allergy)
- ]]>Hydroxyzine]]> (Vistaril)
- ]]>Cyproheptadine]]> (no brand name)
- ]]>Fexofenadine]]> (Allegra)
- ]]>Loratadine]]> (Claritin)
- ]]>Acrivastine]]> (Semprex)
- ]]>Cetirizine]]> (Zyrtec)
- ]]>Doxepin]]> (Prudoxin, Sinequan, Zonalon)
- ]]>Levocetirizine]]> (Xyzal)
- H2 blocking medications such as:
- Anti-inflammatory medications
- Steroid skin creams
- Oral steroid medications ( ]]>prednisone]]> ) for hives resistant to other treatments
- Ultraviolet light therapy
- Prescription ]]>epinephrine]]> (adrenalin) injections for cases when swelling affects the airways
American Academy of Allergy, Asthma, and Immunology
American Academy of Dermatology
Canadian Dermatology Association
Dibbern DA Jr. Urticaria: selected highlights and recent advances. Med Clin North Am. 2006;90:187-209. Review.
Gambichler T, Breuckmann F, Boms S, Altmeyer P, Kreuter A. Narrowband UVB phototherapy in skin conditions beyond psoriasis. J Am Acad Dermatol. 2005;52:660-670. Review.
Guldbakke KK, Khachemoune A. Etiology, classification, and treatment of urticaria. Cutis. 2007;79:41-49. Review.
National Institute of Arthritis and Musculoskeletal and Skin Diseases website. Available at: http://www.niams.nih.gov/ .
Skin biopsy. EBSCO Health Library website. Available at: http://www.ebscohost.com/thisTopic.php?marketID=15topicID=81 . Updated October 2007. Accessed June 17, 2008.
Tips to remember: allergic skin conditions. American Academy of Allergy, Asthma, and Immunology website. Available at: http://www.aaaai.org/patients/publicedmat/tips/allergicskinconditions.stm . Accessed July 7, 2008.
Urticaria/angioedema. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated June 2008. Accessed July 7, 2008.
Urticaria – hives. American Academy of Dermatology website. Available at: http://www.aad.org/public/publications/pamphlets/skin_urticaria.html . Updated June 2008. Accessed July 7, 2008.
Last reviewed November 2008 by ]]>Ross Zeltser, MD, FAAD]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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