Understanding Autoimmune Hives: When the Body Attacks Itselfby Rachel Zohn Health Writer
Many people who suffer from chronic hives hope to identify what is causing the itchy, circular welts that can spread all over a person’s body. But the majority of chronic hives cases are considered idiopathic, meaning there is no identifiable trigger. This condition can be extremely frustrating for patients and their doctors who are trying to find an effective treatment. Some research shows that many of these cases are actually autoimmune in nature, which could lead to a better understanding and possible more targeted treatment.
Chronic Hives May Be the Result of an Underlying Disease
Chronic hives, or hives that last for six weeks or longer, may be the result of an allergic reaction to a food, medication, insect, chemical, or something else in the environment. About one in every 1,000 people are estimated to experience chronic hives, or urticaria. Studies show that 30-40 percent of cases of chronic hives may be the result of an underlying disease, such as an autoimmune disease. But experts also believe that some cases of chronic hives develop from the body’s own immune defenses.
Chronic Idiopathic Hives May Stem From One's Own Immune System
When the body reacts to allergens, it releases histamine and other chemicals that cause inflammation and fluid to accumulate under the skin. According to the American Osteopathic College of Dermatology, about half of the cases of chronic idiopathic hives stem from a person’s own immune system, which has become overactive and begins attacking normal tissues, causing hives. In these cases, patients make an autoantibody that activates their mast cells on the surface of their skin.
A Person's Own Immune System Causes Autoimmune Hives
Mast cells are cells in the skin and mucous membranes that contain histamine. Release of histamine can cause a person to experience allergic symptoms, such as hives or swelling. When this reaction is caused by a patient’s own immune system and not an allergen, it’s known as autoimmune hives.
Autoimmune Hives Start With a Glitch in the Mast Cells
Patients with autoimmune hives have a certain glitch in which autoantibodies have bonded onto a receptor on the mast cell. The autoantibodies trick the mast cell into believing that it has encountered an allergen. The results are hives and tissue swelling, known as angioedema. It also explains why it’s impossible to determine a cause in so many hives cases and why finding an effective treatment can be so difficult for so many. The body is attacking itself and causing the symptoms.
Finding an Effective Treatment Can Be Difficult
It may take trial and error to figure out the right combination of medications to control or reduce outbreaks. Often times the first line of medications for chronic hives are non-sedating antihistamines, such as loratadine or fexofenadine, histamine blockers like cimetidine, or anti-inflammation medication such as oral corticosteroids such as prednisone.
Medications for Difficult-to-treat Chronic Hives
When those treatments aren’t effective, doctors may try man-made antibodies like omalizumab, which are given by injection once a month or immune-suppressing drugs like cyclosporine.
Stress and Hormonal Changes Can Worsen Symptoms
Many people with autoimmune hives feel that their hives are more likely to occur when they are stressed. Some women feel like hormonal changes they experience around their around menopause and during their menstrual cycle may trigger their hives.
Hives Linked to Underlying Autoimmune Disease
Hives are also associated with having an underlying autoimmune disease. Hives have been linked to thyroid disease, rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s syndrome, celiac disease, Raynaud’s syndrome, vitiligo, and type 1 diabetes. However, hives have most commonly been linked to having an autoimmune thyroid disease such as Hashimoto’s disease, which is a form of hypothyroidism, or underactive thyroid.
Hashimoto's Disease and Hashimoto's Thyroiditis
Hashimoto’s disease is when your immune system begins to attack your thyroid. The body makes antibodies that damage the thyroid gland, located at the base of your neck, causing it to become inflamed – this is called Hashimoto’s thyroiditis. Hashimoto’s disease is the most common cause of hypothyroidism. Symptoms include fatigue, brain fog, sensitivity to cold, constipation, dry skin, hair loss, unexplained weight gain, muscle and joint pain.
The Link Between Chronic Hives and Thyroid Antibodies
Studies have found a high prevalence of thyroid autoimmune disorders in patients with chronic hives. This population has a significantly higher amount of thyroid antibodies. Hashimoto’s thyroiditis, specifically, was found to be more frequent in patients with chronic hives than those without.
Doctors Are Still Trying to Understand the Connection
While the link between chronic hives and autoimmune thyroid disease has been documented through various studies, doctors are still trying to understand the degree of connection between the two. Some doctors hypothesize that if your immune system begins making antibodies that attack a part of your own body (such that would cause hives), it’s possible that your immune system may also begin attacking other parts, such that would cause Hashimoto’s.
Ask to Be Tested If You're Concerned
Some doctors recommend that if you are battling chronic hives and have already been tested for allergies in hopes of finding a cause, it would also make sense to test to have your thyroid checked. Ask for a thyroid panel that includes thyroid antibodies, which would show if there is a possible autoimmune issue that could be addressed.