Autoimmune urticaria

Urticaria

Autoimmune Urticaria is a chronic skin condition characterized by the development of hives (urticaria) that appear without an apparent external cause and are thought to be the result of the body's immune system attacking its own tissues. This condition falls under the broader category of chronic spontaneous urticaria (CSU), where hives appear for more than six weeks with no identifiable trigger. Autoimmune urticaria specifically implicates the immune system's role in the persistence and severity of symptoms.

Causes and Pathophysiology

Autoimmune urticaria is believed to be caused by autoantibodies, primarily IgE (Immunoglobulin E) and IgG (Immunoglobulin G), targeting the high-affinity IgE receptor (FcεRI) or IgE itself on the surface of mast cells and basophils. This interaction leads to the release of histamine and other inflammatory mediators, causing the symptoms associated with urticaria, such as redness, swelling, and intense itching.

Symptoms

The primary symptom of autoimmune urticaria is the appearance of red, raised, and itchy welts on the skin. These welts can vary in size and can appear anywhere on the body. Angioedema, which is swelling in the deeper layers of the skin, often accompanies urticaria and can be particularly severe around the eyes, lips, and sometimes the throat.

Diagnosis

Diagnosis of autoimmune urticaria involves a thorough medical history and physical examination, along with laboratory tests to rule out other causes of chronic urticaria. The autologous serum skin test (ASST) is one method used to identify autoimmune urticaria, where the patient's own serum is injected into the skin to see if it causes a wheal and flare reaction, indicative of an autoimmune component. Additional tests may include measuring levels of autoantibodies against IgE or its receptor.

Treatment

Treatment of autoimmune urticaria aims to control symptoms and improve quality of life. First-line treatments include non-sedating antihistamines, which are often used at higher than standard doses. For patients who do not respond to antihistamines, other options include omalizumab (an anti-IgE monoclonal antibody), leukotriene receptor antagonists, and immunosuppressants like cyclosporine. Lifestyle modifications and avoidance of known triggers, if any, are also recommended.

Prognosis

The prognosis for autoimmune urticaria varies. While some individuals may experience remission, others may have persistent symptoms that require long-term management. The condition can significantly impact quality of life, leading to sleep disturbances, anxiety, and depression.

Epidemiology

Autoimmune urticaria is a relatively common form of chronic spontaneous urticaria, with a significant proportion of CSU patients having an autoimmune basis for their condition. It can affect individuals of any age but is most commonly seen in adults, with a higher prevalence in females.