Chronic urticaria is classified as spontaneous if symptoms appear without a known specific trigger, and can occur as a single episode or repeated episodes.
Chronic spontaneous urticaria affects approximately one percent of the global population, most commonly females age 30 to 50 years.
Symptoms of chronic spontaneous urticaria last for at least three years in approximately 66% of patients.
Most patients with chronic spontaneous urticaria develop only wheals(57%) , 37% have wheals and angioedema, and 6% have only angioedema.
In some patients with chronic spontaneous to carry the disease can be exacerbated by stress, nonsteroidal, anti-inflammatory drugs and infections.
Because spontaneous attacks occur without identifiable triggers prevention is not possible.
Chronic spontaneous urticaria has skin mast cells as its primary driver.
In most patients with spontaneous chronic urticaria IgG and IgE immunity can occur and contribute to the activation and degranulation of skin mast cells.
Less than 35% of patients with chronic spontaneous urticaria have no autoantibodies.
The linking of IgG and IgE autoantibodies on skin mast cells activate cytoplasmic signaling proteins, resulting in the release of vasoactive substances, including histamine, the major contributor to urticaria symptoms, and cytokines, leading to activation of sensory nerves, vasodilation, and increased vascular permeability and migration of immune cells, such as eosinophils, T lymphocytes, and basophils into the skin.
The susceptibility to chronic urticaria may be determined by genetic factors, gut microbiome alterations and levels of short chain fatty acid producing bacteria.
With chronic spontaneous a carrier patients develop individual wheals, ranging from a few millimeters to several centimeters in diameter and typically appear and disappear within a single day, usually within a few hours, whereas angioedema typically lasts one to three days.
The wheals blanche, and can have irregular borders, change shape, and appear anywhere on the body.
Wheals chronic spontaneous urticaria most commonly occur on the arms, legs, and trunks, while associated angioedema commonly involves the face, especially the lips and eyelids, but can also affect other body parts in severe disease.
Among patients with chronic spontaneous urticaria and angioedema affects children less frequently than adults and female predominance may be less common in children compared with adults.