Chronic Spontaneous Urticaria (CSU): looks like an allergy, but it isn’t

CSU is the medical term for chronic hives that last for six weeks or longer, where the underlying cause is internal rather than exposure to any allergen or external trigger.1-3 CSU is an immune-related condition but may be mistaken for an allergic reaction, making it difficult to diagnose and manage.4-6

Living with CSU

Approximately 1.7 million people in the US live with the unpredictable onset of symptoms associated with CSU, which can include long-lasting hives, itching, and deep tissue swelling (angioedema).3,7 People may experience burning, stinging, and sometimes pain on the skin where hives occur. Also, in those that experience angioedema, it may affect body areas such as lips, eyes, cheeks and extremities and is associated with numbness/tingling.  These symptoms can have a severe impact on daily life.  

People living with CSU often search tirelessly for an external trigger for their symptoms

The symptoms associated with CSU, such as hives, itching and swelling mimic an allergic reaction, which is why significant time is often spent searching for an external “trigger,” such as an allergy to food, animals, or washing detergents. The exhaustive search for this elusive trigger often results in people making lifestyle changes, such as cutting things out of their diet, but still not finding relief. This constant hunt for an external reason for hives or angioedema may be frustrating and tiring and can last for months or years. 

While a doctor may run tests to eliminate other conditions, there is no one biological marker for diagnosing CSU and diagnosis relies on physical examinations and tracking symptoms. Even with a formal diagnosis of CSU, people may still relentlessly search for an external trigger, hoping to find an outside answer to their CSU symptoms when the underlying cause is internal.

The reality of uncontrolled symptoms

Currently, some antihistamines are the first-line treatment in CSU. However, approximately 50% of people do not achieve complete control of their symptoms, which means that they continue to live with the distressing symptoms of the condition.3,8 As a result, people tend to resign themselves to a life of coping and continue to take antihistamines even if they do not fully relieve their symptoms.

Novartis is committed to raising awareness of CSU and working to address the unmet needs that exist for the community.


  1. Maurer M, Costa C, Gimenez Arnau A, et al. Clin Exp Allergy. 2020;50:1166-1175
  2. Powell RJ, Leech SC, Till S, et al.  Clin Exp Allergy. 2015;45:547-565
  3. Maurer M, Weller K, Bindslev-Jensen C, et al. Allergy. 2011;66:317-330.
  4. Goldstein S, Eftekhari S, Mitchell L, et al.  Annals of Allergy, Asthma & Immunology. 2018;121(5):S35. 
  5. Maurer M, Abuzakouk M, Bérard F. Allergy. 2017;72(12):2005-2006.
  6. Everyday Health. Available from: [Last accessed: August 2023].
  7. The World Bank. Available at: [Last accessed: August 2023].
  8. Guillen-Aguinaga S, Jauregui Presa I, Aguinaga-Ontoso E, et al.  Br J Dermatol. 2016;175:1153­–1165.