When It's Not Just a Rash. Hives, urticaria, Angiodema, Symptoms and Treatments.
What are Hives? Hives, also known as Urticaria, is a type of skin rash characterized by an outbreak of pale or dark red, swollen, raised bumps or plaques (wheals) which usually itch but can also produce a burning or stinging sensation. These often appear suddenly, either as an allergic reaction or for no apparent cause. Hives can vary in size from about a few millimeters to the approximate size of a dinner plate. Hives can be round, ring-shaped or form giant patches. When they join together, they are known as plaques or wheals.
The length of time hives will last can depend greatly upon what triggered the initial outbreak. Most outbreaks of hives which last less than six weeks (acute urticaria) are the result of an allergic trigger. Hives lasting longer than six weeks (chronic urticaria) are rarely due to an allergy. Single hives often only last from a few hours to a day before fading.
Approximately 5% of all people will develop some form of hives in their lives and at least some studies indicate that women are more prone than men for getting this condition. Most patients with chronic urticaria have an idiopathic (unknown) cause, with some studies placing that figure as high as 80%. Other studies estimate that approximately 30%-40% of those with chronic urticaria may actually have an autoimmune disorder. A common symptom of hives is that the size, shape and location of the hives can change rapidly.
Different Types of Hives:
- Acute Urticaria - This type of hives generally only lasts for up to six weeks and is most often due to a severe allergic reaction, often from food allergies such as shellfish or nuts. It often appears only a few minutes after being exposed to the allergen.
- Chronic Urticaria - This type of hives tends to last longer than six weeks with some cases having lasted 20 years or more. This is also the type of hives that is usually considered to be triggered by an unknown problem, though more recent studies are indicating that there may be other, autoimmune indicators. Within the last decade, it has been shown that approximately 1/3 of those with chronic urticaria spontaneously develop auto-antibodies to a receptor located on skin mast cells. More than 50% of those with chronic urticaria have it last a year or more. It lasts 20 years or more in about 20% of sufferers.
- Drug-induced Urticaria - As the name would suggest, this is the result of hives which occur after a reaction to a drug and is often life threatening, having been known to result in severe cardiorespiratory failure. Shock, difficulty breathing and anaphylaxis are not uncommon due to drug-induced Urticaria, though these have also been known to affect those with acute urticaria if the trigger is an instinct sting or severe food allergy.
- Physical Urticaria - Hives which occur due to physical stimuli. These can include but are not limited to: Reactions to water; Reactions to heat (including body heat); Reactions to cold; Reactions to adrenaline; and most frequently, reactions to scratches (dermatographic urticaria).
Diagnosis of Hives: As one of the hallmarks of hives is their tendency to appear rapidly, disappear and reappear just as rapidly, change size, shape and even location, a doctor can usually make a diagnosis of hives as few other skin disorders have such characteristics. Even if the hives should disappear, it is often a good idea to seek medical treatment as these can and usually do reappear, as certain treatments may lessen the severity and shorten the outbreak. If possible, take a photograph of the hives at its worst so the doctor can be better assisted in the diagnosis.
It is important to remember that other rashes, especially other rashes brought about by allergic reactions (such as due to poison ivy and poison oak) or often mistaken for hives. If you have spent time outdoors or think you might have come into something unusual, including foods, insects plants or medications, it is important to inform your doctor.
Treatment of Hives: As acute urticaria is usually the result of an allergic reaction, treatment often involves taking an antihistamine. Short-term treatment may also involve taking a corticosteroid (such as Prednisone), though this may cause side effects and is often not recommended for long-term use.
Chronic urticaria can be much more difficult to treat, with an emphasis often placed on avoiding the triggers. It can be difficult to determine which medications to use as many are known to spontaneously lose their effectiveness while others may take a few days before they can properly work. Some research is being done looking into the effectiveness of tricyclic antidepressants while at least one company is researching the use of certain types of hormones.
What is Angiodema? Angiodema is similar to hives except that the rapid swelling occurs under the skin. This is often characterized by swelling around the eyes or mouth, less frequently around the hands and feet. Occasionally, swelling can occur within the mouth, tongue or even the throat. This can be life-threatening as it can severely restrict the airways, causing difficulty in breathing. For this reason, when Angiodema is suspected, it is imperative to immediately get to a doctor or hospital.
Symptoms of Angiodema: The skin of the face, usually around the eyes and mouth, swells up between a period of a few minutes to a few hours. Often this can result in the patient's inability to open the eyes. Swelling on the hands and feet or also common. Other swelling can occur on the genitals, trunk, limbs and within the body, such as the digestive tract. It can become life-threatening when the swelling occurs in the mouth and throat as this can hamper or even prevent the flow of oxygen.
The swelling can be extremely itchy or painful, sometimes being described as a feeling of being stung. In addition, hives can often accompany angiodema. Though it tends to last longer than hives, the swelling will usually subside within 24 hours. he diagnosis of Angiodema is usually clinical, with routine blood tests being performed. Skin tests may also be performed when this is suspected. Most occupancies of Angiodema are due to allergic reaction though many forms are chronic and often hereditary. In hereditary angiodema, often there is no direct cause for the onset, though it has been noted that traumas (even including dental work) may create a trigger.
Treatment of Angiodema: With allergic Angiodema, treatment is again focused on the avoidance of the allergen or with antihistamines. A commonly prescribed antihistamine for this is Cetrizine, with many patients expressing positive results taking a low dosage of this at night along with stronger doses during a flare. Zyrtec is now an over-the-counter form of Cetrizine in both the United States and Canada.
Angiodema can be drug induced, with ACE inhibitors being a primary culprit. This is often treated with the usage of ARBs, though it is not always successful.
When angiodema is hereditary, the aim is to halt the progression of the diseases as soon as possible, especially in the elderly. Hereditary angiodema does not respond to epinephrine, corticosteroids or antihistamines. Often, this is treated with donor blood which contains C1-INH, or fresh frozen plasma can be used. Patients who have these flares more than once a month may also be treated with long-term prophylaxis, such as Danazol. Those whose hereditary angiodema is triggered by a trauma may use short-term prophylaxis, which is normally administered before dental work or surgery.
On a final note: Though many sources will tell you to seek immediate medical treatment if hives or angiodema occurs suddenly, there have been cases of more serious symptoms occurring after the initial onset. If these are suspected, get to the doctor immediately. If you feel the symptoms may become life threatening, get to the hospital immediately. When possible, take pictures or keep a journal describing events leading up to and during the outbreak, as these may help with the diagnosis and treatment.
For more information about rashes and other skin disorders, please read: When it's Not Just a Rash (Part 1): Herpes Zoster / VZV and Chicken Pox
All sources are credited in the above article. Photograph courtesy of ICUS http://urticaria.thunderworksinc.com/pages/photos.htm