Difference Between Angioedema and Urticaria

Difference Between Angioedema and Urticaria

What is Angioedema?

Angioedema is swelling that is similar to hives, but the swelling is under the skin instead of on the surface.

Hives are often called welts. They are a surface swelling. It is possible to have angioedema without hives.

Causes of Angioedema

Hives and angioedema can be caused by:

  • Foods. Many foods can trigger reactions in people with sensitivities. Shellfish, fish, peanuts, tree nuts, eggs and milk are frequent offenders.
  • Medications. Almost any medication may cause hives or angioedema. Common culprits include penicillin, aspirin, ibuprofen (Advil, Motrin IB, others), naproxen (Aleve) and blood pressure medications.
  • Common allergens. Other substances that can cause hives and angioedema include pollen, animal dander, latex and insect stings.
  • Environmental factors. Examples include heat, cold, sunlight, water, pressure on the skin, emotional stress and exercise.
  • Underlying medical conditions. Hives and angioedema also occasionally occur in response to blood transfusions, immune system disorders such as lupus, some types of cancer such as lymphoma, certain thyroid conditions, and infections with bacteria or viruses such as hepatitis, HIV, cytomegalovirus, and Epstein-Barr virus.
  • Genetics. Hereditary angioedema is a rare inherited (genetic) form of the condition. It’s related to low levels or abnormal functioning of certain blood proteins that play a role in regulating how your immune system functions.

Symptoms of Angioedema

The main symptom of angioedema is swelling that develops below the skin’s surface.

Swollen skin

Swelling caused by angioedema can develop suddenly or come on gradually over a few hours. It normally lasts a few days.

The swelling most often affects the:

  • hands
  • feet
  • area around the eyes
  • lips and tongue
  • genitals

In severe cases, the inside of the throat or bowel can be affected.

Rash

Often, the swelling occurs with a raised, itchy rash called urticaria (hives).

The rash will usually settle in a few days.

Otherwise, the skin over the swelling may feel tight and painful but look normal.

Other symptoms

Less common symptoms of angioedema include:

  • difficulty breathing
  • red, irritated eyes (conjunctivitis)
  • tummy (abdominal) pain
  • feeling sick
  • diarrhoea
  • dizziness
  • fainting

Treatments for Angioedema

The treatment for angioedema depends on the cause, but the most important action is to ensure a free airway. This means that in an emergency, a breathing tube might be placed for safety.

An allergic reaction may be treated with epinephrine, which is the drug in an EpiPen. Other medications include antihistamines and corticosteroids.

If the cause is hereditary, the patient may receive a concentrate of the the C1 inhibitor, the protein they are missing, and fresh frozen plasma.

Where appropriate, identifying and avoiding the allergen that leads to angioedema is key to preventing the occurrence of this condition.

What is Urticaria?

Urticaria is characterised by weals (hives) or angioedema (swellings, in 10%) or both (in 40%). There are several types of urticaria. The name urticaria is derived from the common European stinging nettle ‘Urtica dioica’.

A weal (or wheal) is a superficial skin-coloured or pale skin swelling, usually surrounded by erythema (redness) that lasts anything from a few minutes to 24 hours. Usually very itchy, it may have a burning sensation.

Angioedema is deeper swelling within the skin or mucous membranes, and can be skin-coloured or red. It resolves within 72 hours. Angioedema may be itchy or painful but is often asymptomatic.

Causes of Urticaria

The welts that come with hives arise when certain cells release histamine and other chemicals into your bloodstream.

Doctors often can’t identify the reason for this skin reaction, or why it sometimes turns into a long-term problem (chronic hives). But the skin reaction may be triggered by:

  • Pain medications
  • Insects or parasites
  • Infection
  • Scratching
  • Heat or cold
  • Stress
  • Sunlight
  • Exercise
  • Alcohol, food or food additives
  • Pressure on the skin, as from a tight waistband

Symptoms of Urticaria

  • The appearance of the rash and the itch can cause distress.
  • A related condition called angio-oedema occurs from time to time in some people with persistent hives (chronic urticaria). In this condition some fluid also leaks into deeper tissues under the skin, which causes the tissues to swell:
    • The swelling of angio-oedema can occur anywhere in the body but most commonly affects the eyelids, lips and genitals.
    • Sometimes the tongue and throat are affected and become swollen. The swelling sometimes becomes bad enough to cause difficulty breathing.
    • Symptoms of angio-oedema tend to last longer than urticarial weals. It may take up to three days for the swollen areas to subside and go.
  • A variation called vasculitic hives occurs in a small number of cases. In this condition the weals last for more than 24 hours, they are often painful, may become dark red and may leave a red mark on the skin when the weal goes. Technically, this type of rash is not urticaria.

Treatments for Urticaria

The main treatment of all forms of urticaria in adults and in children is with an oral second-generation antihistamine chosen from the list below. If the standard dose (eg 10 mg for cetirizine) is not effective, the dose can be increased up to fourfold (eg 40 mg cetirizine daily). They are stopped when the acute urticaria has settled down. There is not thought to be any benefit from adding a second antihistamine.

  • Cetirizine
  • Loratidine
  • Fexofenadine
  • Desloratadine
  • Levocetirizine
  • Rupatadine
  • Bilastine

Terfenadine and astemizole should not be used, as they are cardiotoxic in combination with ketoconazole or erythromycin. They are no longer available in New Zealand.

Although systemic treatment is best avoided during pregnancy and breastfeeding, there have been no reports that second-generation antihistamines cause birth defects. If treatment is required, loratidine and cetirizine are currently preferred.

Conventional first-generation antihistamines such as promethazine or chlorpheniramine are no longer recommended for urticaria:

  • They are short-lasting.
  • They have sedative and anticholinergic side effects.
  • They impair sleep, learning and performance.
  • They cause drowsiness in nursing infants if taken by the mother.
  • They interact with alcohol and other medications.
  • Lethal overdoses are reported.

What is the Difference Between Angioedema and Urticaria?

Urticaria is characterised by weals (hives) or angioedema (swellings, in 10%) or both (in 40%).

A weal (or wheal) is a superficial skin-coloured or pale skin swelling, usually surrounded by erythema (redness) that lasts anything from a few minutes to 24 hours. Usually very itchy, it may have a burning sensation.

Meanwhile the Angioedema is deeper swelling within the skin or mucous membranes, and can be skin-coloured or red. It resolves within 72 hours. Angioedema may be itchy or painful but is often asymptomatic.

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