What exactly is urticaria

Urticaria is a heterogeneous disease characterized by the sudden appearance of wheals or hives, angioedema or both.

That is to say, red lesions, with volume of different sizes that usually itch and that change shape and size, appearing and disappearing in less than 24 hours. On some occasions, angioedema may be added to this condition, or appear alone, i.e. a sudden inflammation, usually of the same color as the skin, which may itch and even cause pain, mainly in the face (eyes, lips) and uvula.

It is the most frequent dermatological disease seen in the emergency department.

Why do they appear? What causes them?

In urticaria it is produced by the release of molecules such as histamine, produced by a type of cells called mast cellsā€¦ Histamine is the cause of edema, swelling and itching characteristic of urticaria. The induction of urticaria (by mast cell degranulation) may be due to various agents.

Urticaria can be classified according to duration, trigger and cause.

According to the duration it can be acute (if its symptoms are less than or equal to six weeks) or chronic (if its symptoms last more than six weeks).

According to the trigger, we will have spontaneous urticaria (which will be the majority, and will be those in which there is no external trigger) or inducible urticaria (where the symptoms have a specific trigger, such as temperature, pressureā€¦).

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Depending on the cause, we differentiate between urticaria with known cause (autoimmune, infection, others) or urticaria of unknown cause.

Spontaneous chronic urticaria is the most frequent at present.

In addition, we should know that not all urticaria or angioedema implies allergy.

Can it affect anyone and is there a profile more prone to suffer from it?

The prevalence in women is twice as high as in men. And the most frequent age of onset is between 20 and 40 years of age, although it can appear at any age, both pediatric and geriatric.

Moreover, we should know that chronic urticaria (i.e. urticaria lasting more than 6 weeks) affects 0.6% of the general population.

What are its symptoms?

Its guiding symptoms are hives or wheals and angioedema if it occurs:


It is characterized by:

  • Central swelling surrounded by reflex erythema in the middle and upper layers of the dermis.
  • Associated itching (pruritus) or, sometimes, stinging sensation.
  • Evanescent (disappearing in


Characterized by:

  • Pronounced swelling, edematous and with slight erythema.
    in the deeper layers of the dermis, lower dermis and subcutis or
    and subcutis or mucous membranes and subcutaneous or submucosal tissue.
  • It sometimes causes more pain than itching.
  • It has a slower resolution than wheals
    (it can last up to 72 hours).

How long does it last?

In most cases hives are less than six weeks in which the lesions appear and disappear during this period.

But in the case of urticaria longer than six weeks, i.e. chronic urticaria, the average duration is one to five years.

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How can it be treated and what options are available?

It is essential for a dermatologist to take an anamnesis (medical history) of the patient.

If we know the cause (for example, a drug) we should avoid the substances that provoke urticaria.

In acute urticaria there are no standardized treatments, but it is recommended not to ingest foods or drugs that can worsen the urticaria such as aspirin and its derivatives, codeine and morphine, dyes, preservatives, nuts, fermented beverages (beer and wine), fermented cheeses (cured cheeses), deli products, seafood, canned foods, tomatoes, strawberries, bananas, pineapple and apples, frozen fish, convenience foods.

The main treatment for urticaria is antihistamines (nowadays we use second generation antihistamines which do not cause drowsiness in most cases). We should keep a strict control of the dosage and duration and inform our dermatologist of how we feel. In severe, extensive cases that do not respond to antihistamines, nowadays we have biological treatments such as Omalizumab (Xolair) with great success and efficacy in our patients.

In cases of airway compromise, patients should carry subcutaneous adrenaline for immediate administration in case of shortness of breath due to laryngeal inflammation.

For more information on urticaria, please consult a specialist in Dermatology.