Chronic Autoimmune Urticaria (CAU)

Understanding CAU

Urticaria is the medical name for hives. These are welts, or pink swellings, which come up on any part of the skin. In some cases, urticaria is due to an allergic reaction to a variety of things (for example, foods, insect stings, medications, and exposure to sunlight, cold, pressure, vibration or exercise). Hives lasting longer than 6 weeks are called chronic urticaria. When there is no known cause, as is true for the majority of these cases, it is known as chronic idiopathic urticaria. In about half of patients with chronic idiopathic urticaria, the cause is autoimmune, which is when the immune system malfunctions and attacks and causes damage to a part of the body (in this case, skin tissue). When due to an autoimmune problem, the urticaria is known as chronic autoimmune urticaria (CAU).

Symptoms of CAU

Hives itch and each individual hive lasts a few hours before fading away, leaving no trace. New hives appear as old areas fade. They can be pea sized or join to cover broad areas of the body. While the itch can be intense, the skin is usually not scabbed or broken. In some people the hives burn or sting. Hives can sometimes occur in deeper tissues of the eyes, mouth, hands or genitals. These areas may develop a swelling and is called angioedema.

Diagnosing CAU

The health care provider may first rule out allergies, perform allergy testing, and review medical history for other autoimmune conditions. Chronic Urticaria Index, a blood test for certain autoantibodies, may be helps diagnose CAU.

Treatment of CAU

Patients with proven chronic autoimmune urticaria (CAU) are initially treated in exactly the same way as patients with chronic idiopathic urticaria. Antihistamines remain the initial treatment of choice. Patients with CAU often have severe disease and respond poorly to antihistamines. For these patients, treatments include oral immunosuppressive medications (for example, cyclosporine, tacrolimus, methotrexate, and hydroxychloroquine), biologic medication injected under the skin subcutaneously (for example, omalizumab/Xolair^®), plasmapheresis, and immune globulin therapy administered into the blood stream intravenously (IVIG). Plasmapheresis (also known as apheresis, plasma exchange, or “plex”) is a medical procedure where a device separates whole blood into the cellular components and plasma. The plasma is then discarded and replaced with a colloid fluid, combined back with the cellular components, and returned to the same patient.

References:

• Urticaria | American Osteopathic College of Dermatology
• Goh CL, Tan KT. Chronic autoimmune urticaria: where we stand?. Indian J Dermatol. 2009;54(3):269-274. doi:10.4103/0019-5154.55640