Urticaria is a medical term for a rash that looks like red itchy bumps. They often look like big mosquito bites. Other
common terms are hives, welts, or wheals. Urticaria is a common condition and will affect at least 15-20% of the
general population at some time in their lives. It can be a very frustrating condition because they can be very itchy and
the cause can be difficult to determine.
Appearance: The skin rash appears as bumps on the skin which can vary in size from pinhead sized to large areas
several inches across. The individual lesions usually start as well demarcated, well circumscribed bumps but can grow
and coalesce into larger areas involving most or all of an extremity or torso. The lesions usually have a reddish color,
and they blanch (become white) on direct pressure. Hives may last for a few minutes, up to hours, and occasionally
up to 24 hours. The individual lesions usually come and go in less than 24 hours to be replaced by other newer lesions
which in turn last less than 24 hours. Urticaria can occur for only a brief time of a few days, but they can also occur
daily for many months or even years. Once the individual lesions disappear, there are no residual marks or scars. If
dark, discolored marks remain on skin after the hives have resolved this may suggest underlying medical illness.
Causes of urticaria:
Hives can be due to many things. At least 50% of the time, no cause is found. Common causes include:
- Allergy: food, drugs, herbal medicines, supplements, food dyes, and rarely inhalants (ie pets, dust, pollen)
- Viral infections
- Other infections: parasites, viral disease, sinusitis, hepatitis, dental disease (such as a dental abscess), fungal
infections, and others.
- Travel (parasites, malaria and other infections)
- Pregnancy (usually in first trimester)
- Liver or kidney disease
- Thyroid disorders
- Stomach ulcers or gastritis associated with infection by H. Pylori (a common cause for stomach ulcers)
- Cancer (rarely)
- Contact allergy to cosmetics, creams, lotions, chemicals, jewelry.
- Insect stings
- Physical triggers: exercise, heat, pressure, cold, water, sweating, vibration, sun light and others.
- Stress/anxiety (common)
Angioedema occurs when the swelling develops in the deeper tissues of the skin or mucosal surfaces of the body.
This differs from hives (urticaria) where the swelling develops in the superficial areas of the skin. Angioedema often
involves the face, tongue, lips, throat, feet, the lining of the intestines, and genitalia. The swelling may be painful or
burning in character rather than itchy. Occasionally the tongue or throat swelling may be so bad enough that it causes
breathing difficulties – which can be life threatening. Most of the time, angioedema occurs at the same time as the
hives develop. Rarely, angioedema may appear alone – without any hives at all, and in these cases, it may be due to
a hereditary disorder called hereditary angioedema.
What to expect in an appointment with your allergist for the evaluation of urticaria and angioedema:
- The doctor will take a thorough history to find out the pattern of hives and to look for a possible trigger.
- The doctor will do a physical exam looking at the skin and looking for any other signs of disease.
- There may be allergy testing done if indicated. This can only be done if the patient is not taking antihistamine
medicines and not having significant hives at the time of the appointment (as this can cause false skin test
- Some blood work may be ordered
- The doctor will discuss possible causes, triggers and exacerbating factors and make recommendations on
medications and life style changes.
- Avoidance of triggering or exacerbating factor if identified
- Avoid factors that may make hives worse: this includes aspirin and other non-steroidal anti-inflammatory drugs
(ie ibuprofen or motrin, Aleve,…), alcohol, stress, temperature extremes, exercise.
- Most urticaria can be controlled with a once daily antihistamine medicine. Sometimes more than one
medication is required for control. Your allergist will help you determine which types of medications may be
most effective for your condition.
- Epinephrine (in form of an Epi-Pen or Auvi-Q) may be prescribed for severe urticaria if upper airway
symptoms or swelling are suspected.
What is urticaria (hives)
Picture of pressure urticaria, also
known as dermatographism.
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