**Abstract**

Chronic urticaria can be subclassified into chronic spontaneous urticaria and chronic inducible urticaria. Up to 30% of cases are associated with functional immunoglobulin G antibodies to the high affinity immunoglobulin E receptor FcεRIα or to immunoglobulin A. Pathogenic activation of mast cells and basophils gives rise to release of pro-inflammatory mediators that lead to development of hives. CSU is a debilitating disease with a relapsing course. It affects 0.5–1% of the population at any given time. The duration of CSU is generally 1–5 years but can be longer in cases associated with angioedema and autoreactivity. CSU has detrimental effects on life quality with sleep-deprivation and psychiatric disorders being the most frequent. In a great number of patients an underlying cause or eliciting factor cannot be identified. Among the patients in which an aetiology is suspected, infections, medication, food and psychological factors are most commonly associated. A potential autoimmune cause has been reported in up to 50% of patients. Chronic inducible urticaria is characterised by its ability to be triggered consistently and reproducibly in response to a specific stimulus (pressure, temperature, vibration, water, heat, light). Antihistamines form the mainstay of therapy. In recalcitrant chronic urticaria, a variety of other drugs have been tried.

**Keywords:** Wheals, Angioedema, Chronic Spontaneous Urticaria, Chronic Inducible Urticaria, Classification, Prevalence, Histamine-mediated, Pathophysiology, anti-IgE, anti-FcεRI, Autoallergy, anti-TPO, Autoimmune urticaria, Vitamin D, Pseudoallergens, Stress, associated conditions, Predictors of severity, Diagnosis, Medical History, Histopathology, Check List, Clinical signs, Differential Diagnosis, Guidelines, Patient reported outcomes, UAS7, DLQI, Socio-economic burden, Patient characteristics, real-world study, Refractory chronic urticaria, Treatment, Antihistamines, Omalizumab, Leukotriene receptor antagonist, oral corticosteroids
