What Are Hives?
Hives, also known as
urticaria, are itchy, raised welts that are found on the skin. They are usually
red, pink, or flesh-colored, and sometimes sting or hurt. In most cases, hives
are caused by an allergic reaction to a medication or food or a reaction to an
In many cases, hives are
an acute (temporary) problem that may be alleviated with allergy medications. Most
rashes go away on their own. However, chronic (ongoing) cases, as well as hives
accompanied by a severe allergic reaction, are bigger medical concerns.
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What Causes Hives?
Hives are usually caused
by an allergic reaction to something that you have encountered or swallowed.
When you are having an allergic reaction, your body begins to release
histamines into your blood. Histamines are chemicals your body produces in an
attempt to defend itself against infection and other outside intruders.
Unfortunately, in some people, the histamines can cause swelling, itching, and
many of the symptoms that are experienced with hives. In terms of allergens,
hives can be caused by factors such as pollen, medications, food, animal
dander, and insect bites.
It should be noted that
hives might also be caused by circumstances besides allergies. It is not
uncommon for people to experience hives as the result of stress, tight clothes,
exercise, illnesses, or infections. It is also possible to develop hives as the
result of excessive exposure to hot or cold temperatures or from irritation due
to excessive sweating. As there are many potential causes, many times the
actual cause of hives cannot be determined.
Who Is at Risk?
People who are known to
have allergies are more likely to get hives. You may also be at risk to develop
hives if you are on medication or if you are unknowingly exposed to things you
may be allergic to, such as food or pollen. If you are already ill with an
infection or a health condition, you may be more vulnerable to developing
What Do Hives Look Like?
The most noticeable
symptom associated with hives is the welts that appear on the skin. Welts may
be red but can also be the same color as your skin. They can be small and
round, ring-shaped, or large and of random shape. Hives are usually itchy, and
tend to appear in batches on the affected part of the body. They can grow larger,
change shape, and spread.
Hives may disappear or
reappear over the course of the outbreak. Individual hives can last anywhere
from half an hour to a day and a half. The hives may turn white when pressed.
Sometimes the hives may change shape or form together and create a larger,
raised area. Hives can occur in a variety of places on the body. Call 911 or
seek medical attention immediately if you develop a hive outbreak around your
throat or on your tongue or have trouble breathing along with hives.
Types of Hives
The most common causes of
hives are allergic reactions. These can be caused by any allergen you might be
sensitive to, including:
- foods (such as
nuts, milk, and eggs)
- pet dander
- dust mites
- insect bites
(primarily antibiotics, cancer drugs, and ibuprofen)
Mild cases of hives caused
by allergies are typically treated with long-term or short-term allergy
medications and avoidance of the trigger.
Anaphylaxis is a severe,
life-threatening allergic reaction. In this condition, hives are often
accompanied with breathing difficulties, nausea or vomiting, severe swelling,
and dizziness. Call 911 immediately if you suspect anaphylaxis.
Chronic hives are ongoing
cases that don’t necessarily have an identifiable cause. Also called chronic
urticaria, this condition is marked by recurring hives that can interfere with
your lifestyle. According to the Mayo Clinic, these can last between six weeks and several months or years.
You may suspect chronic
hives if you have welts that don’t go away within six weeks. While not
life-threatening, this form of hives can be uncomfortable and difficult to
treat. They may also be a symptom of an underlying health problem, such as:
- celiac disease
- type 1
This form of acute hives
is considered mild. Excessive scratching or continuous pressure on the skin
causes it. Dermatographism usually clears up on its own in a short period of
time without treatment.
Sometimes changes in
temperature can induce hives in people who are sensitive to such changes. Cold-induced
hives may occur from cold water or air exposure, while body heat from physical
activity may cause exercise-induced hives. Exposure to sunlight or tanning beds
may also bring about solar hives in some people.
Both viral and bacterial infections can cause hives. Common bacterial infections
causing hives include urinary tract infections and strep throat. Viruses that
cause infectious mononucleosis, hepatitis, and colds often cause hives.
Finding Relief: Treatment Options
The first step in getting
treatment is to figure out if you actually have hives. In most cases, your
doctor will be able to determine if you have hives from a physical exam. Your
skin will show signs of the welts that are associated with hives. Your doctor
may also perform blood tests or skin tests to determine what may have caused
your hives — especially if they were the result of an allergic reaction.
You may not need prescription
treatment if you are experiencing a mild case of hives not related to allergies
or other health conditions. In these circumstances, your doctor might suggest
that you seek temporary relief by:
antihistamines, such as diphenhydramine or cetirizine
irritating the area
- avoiding hot
water, which may aggravate the hives
- taking a cool
or lukewarm bath with colloidal oatmeal or baking soda
With anaphylaxis, your
doctor will usually use a shot of steroids or epinephrine to relieve the
symptoms more quickly.
Can Hives Be Prevented?
changes to your lifestyle may be able to help you prevent hives from
reoccurring in the future. If you have allergies and you know which substances
are likely to cause an allergic reaction, your doctor will suggest that you
avoid any possible exposure to these factors. Allergy shots are another option
that may help you reduce the risk of experiencing hives again.
being in high-humidity areas or wearing tight clothing if you have recently had
a hives outbreak.
What to Expect
hives can be itchy and uncomfortable, usually they are not severe and will
disappear after a period of time. However, be aware that as some hives go away,
new ones may pop up.
cases of hives are considered harmless. Hives can be dangerous if you are having
a serious allergic reaction and your throat is swelling. Prompt treatment for a
severe case of hives is important for a good outlook.