Facts About Chronic Spontaneous Hives

what is chronic spontaneous urticaria csu infographic

Chronic spontaneous urticaria (CSU) is the medical term for hives that include:

  • No known cause
  • May it last a long time

Chronic = Lasts more than 6 weeks

Spontaneity = no obvious cause or trigger

Hives = red, itchy, raised welts or spots on the skin (hives).

What Causes CSU?

When the immune system detects a threat, it releases histamine and other inflammatory chemicals.

Histamine dilates blood vessels, which can cause skin swelling, itching, and redness.

What causes hives?

Common triggers for hives usually include:

  • allergy
  • Bacterial infections, including UTIs and strep
  • Viral infections, including colds and mono
  • Certain medicines, including antibiotics and ibuprofen
  • extremely hot or cold temperatures

Unlike other types of hives, CSU typically has no identifiable trigger and its cause is unknown. However, it is often associated with type 2 inflammation.

Type 2 inflammation = an excessive immune response that can lead to an inflammatory condition.

CSU treatment

  • Antihistamines are used first
  • Biologics (monoclonal antibodies that target the immune system) if symptoms remain uncontrolled

Help with CSU

If hives last longer than 6 weeks or keep coming back, contact your doctor, dermatologist, or allergist.

This training material was created with support from Regeneron and Sanofi.