Urticaria is a medical term for a skin rash that appears as bumps that are red and itchy. They often look like large
mosquito bites. Other common terms are hives, welts, welps or wheals. Hives occur in 15-20% of the general
population at some time in their lives, so it is a very common condition. It is generally uncomfortable because of
intense itching of the lesions. Very rarely, the lesions can involve the upper airway (mouth, lips, tongue or uvula)
causing difficulty in breathing.
Appearance: The skin rash appears as bumps on the skin that vary in size from pinhead sized to large areas of a few
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 that
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 inhalant (ie pets, dust, pollen)
- Viral infections, especially in young children
- Other infections: parasites, viral disease, sinusitis, hepatitis, dental disease, candidiasis, and others.
- Travel (parasites, malaria and other infections)
- Pregnancy (usually in first trimester)
- Liver or kidney disease
- Thyroid disorder
- Stomach ulcers or gastritis associated wiht 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.
Types of urticaria:
Acute: Less than 6 weeks. Often in children and young adults, sometimes found to have allergic trigger.
Chronic: more than 6 weeks. In any age group. Usually no allergic trigger found.
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, and genitalia and 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 hives. In these cases, it may be due to a hereditary disorder called hereditary
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
- 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, 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 Twinject) 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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