Chronic spontaneous urticaria is defined by recurrent episodes occurring at least twice a week for ≥ 6 weeks without inducible causes. Females are more commonly affected than males. The etiology of CU is heterogeneous. CU has a significant impact on quality of life. CU is a common skin condition that affects up to 5% of the general population.
IgE plays an essential role in type I hypersensitivity, which manifests various allergic diseases such as allergic asthma, allergic rhinitis, food allergy, some types of chronic urticaria and atopic dermatitis. IgE-mediated autoimmunity or autoallergy against several autoallergens, including thyroid peroxidase, double stranded DNA, IL-24, thyroglobulin and tissue factor, is thought to play a major role in the pathogenesis of CSU.
Interleukin (IL)-18 is a pleotropic cytokine that provides an important link between innate and adaptive immune responses and it can enhance both.It can activate T cells and induce either T-helper (Th) 1 or Th2 responses, depending on the cytokine environment. It has been suggested that IL-18 may play an important role either in autoimmune disorders, characterized by a predominant Th1 response, or in allergic diseases, characterized by a Th2 response.