Fast Facts

Understanding Chronic Spontaneous Urticaria (CSU) and its impact is crucial to optimise treatment outcomes. Here are some key points to help your understanding of this debilitating skin condition.

Fact 1

The following symptoms of CSU can also be caused by allergies:

  • Itching
  • Hives
  • Swelling
  • Interrupted sleep

CSU has no identifiable external trigger, and when the symptoms look the same it’s easy to see why it can be mistaken for an allergic reaction. However, unlike CSU, allergic reactions have a known trigger. When the trigger of symptoms is known this is called chronic inducible urticaria (CIndU). The symptoms of CSU and CIndU are caused by the same underlying process – histamine released from activated mast cells.

Fact 2

Symptoms (itchy hives and/or angioedema) of a single CSU flare typically last more than 6 weeks.

CSU is an unpredictable disease and each individual flare of the symptoms can last between a few hours and a few days (O'Donnell et al., 1997). Symptoms may not be present all of the time, but when a patient has been affected by recurring flares over a period of six weeks or more, for which there is no known trigger, they can be diagnosed with CSU (Zuberbier et al., 2018; O'Donnell et al., 1997).

Fact 3

CSU can affect a patient for up to 50 years.

CSU varies from person to person, and it is not possible to predict the duration of time for which symptoms will be present. For some it can last for weeks, for others it can be months or years, and in rare cases it can last for up to 50 years.

See the epidemiology section for more information.

Fact 4

According to the updated 2017 EAACI/GA2LEN/EDF/WAO guidelines, key components of the CSU diagnosis process are:

  • Patient history
  • Physical examination
  • Diagnostic blood tests
  • Allergy tests

The recently updated EAACI/GA2LEN/EDF/WAO guidelines indicate that after a thorough patient history has been collected, only three tests are needed to confirm a CSU diagnosis: a physical examination, diagnostic blood tests and allergy testing. Exactly which tests are used will depend on the individual patient’s history and condition.

For more information, visit the diagnosis section.

Fact 5

In your patient history assessment, the following should be discussed:

  • Time of onset of disease
  • Family history of wheals and angioedema
  • Allergy history
  • Shape, size and distribution of hives
  • Associated angioedema
  • Associated objective symptoms of pain (e.g., itch, pain)
  • Impact on quality of life
  • Diet
  • Association with physical agents
  • Occurrence in relation to provoking factors such as drug use, menstrual cycle, travel
  • Previous therapy and diagnostics

During diagnosis, the patient evaluation should be thorough and comprehensive. Updated EAACI/GA2LEN/EDF/WAO guidelines suggest a list of questions that cover the appropriate depth and breadth of information to enable you to obtain the best possible patient history record.

For more information, visit the diagnosis section.

Fact 6

Differential blood count and red blood cell sedimentation rate are the first choices for CSU diagnostic tests.

The routine diagnostic tests for CSU assess differential blood count, erythrocyte sedimentation rate (ERS) and C-reactive protein (CRP). These are the only tests that are required to diagnose CSU. However, depending on individual patient history, a range of further extended diagnostic tests are available that may aid identification of underlying causes and rule out possible alternative diagnoses.

For more information, visit the diagnosis section.

Fact 7

The following comorbidities can be associated with CSU:

  • Anxiety
  • Pain
  • Depression

CSU can have a big impact on a patient’s life. The itchy hives, the pain or burning sensation they can cause, the unpredictability of the flares and the aesthetic impact can all lead to patients feeling anxious, depressed and on their own. Sixty three percent of CSU patients report anxiety at some point during their flares (O'Donnell et al., 1997), while 17% are diagnosed with depressive or somatoform disorders (Staubach et al., 2011).

For more information visit the epidemiology section.

Fact 8

More than 80% of CSU patients experience sleep disruption because of their condition. 92% of patients report sleep disruption as a direct result of their CSU symptoms and 22% claim that tiredness is the worst aspect of their condition (O'Donnell et al., 1997).

Fact 9

Personal relationships are affected by CSU symptoms. 73% of CSU patients report that their sexual relationships are directly affected by their condition (O'Donnell et al., 1997).

For more information visit the epidemiology section.

Fact 10

Chronic urticaria (CU) affects approximately 1% of the population. At least 2/3 of patients with CSU. One third of CU sufferers have a known trigger for their condition (e.g. cold, heat, physical exercise, or UV light) (Maurer et al., 2011), and two thirds will not know the exact cause (Maurer et al., 2013). This is why it is called chronic spontaneous urticaria (or sometimes chronic idiopathic urticaria).

Fact 11

There is currently no known cure for CSU, however there are treatment options that can provide symptomatic relief. The first-choice medications are H1-antihistamines, however less than 50% of patients show adequate symptomatic relief on these drugs (Baiardini et al., 2011; Staubach et al., 2011).

Fact 12

There are currently no validated useful biomarkers for CSU. The severity of CSU should be evaluated based on the intensity of its clinical symptoms. Several substances have shown distinctive patterns in CSU patients, but those molecules have still not been validated as useful biomarkers (Weller et al., 2013).