Hashimoto’s thyroiditis and chronic urticaria

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If you’ve had hives, you know the experience can be both alarming (itchiness, red spots, or bumps can appear out of nowhere) and disrupt your life, preventing you from enjoying your usual activities. while you wait for them to disappear. . In some cases, hives are an isolated incident that occurs as a result of an allergy to a food or drug or an insect bite. But in other cases, they can appear again and again for weeks or even months without any obvious cause.

Doctors call the latter scenario “chronic hives,” and it can be associated with a number of chronic health conditions, including autoimmune disorders. Among them is Hashimoto’s thyroiditis (or Hashimoto’s disease), a condition in which the body attacks the thyroid gland.

If you or someone close to you has Hashimoto and is dealing with hives, read on for more information on chronic hives, the Hashimoto-urticaria link, and how the problem can be treated.

What are chronic hives?

Hives that occur repeatedly for at least six weeks are considered chronic hives or, in medical terminology, chronic hives. Some medical professionals prefer to use the term chronic spontaneous urticaria or chronic idiopathic urticaria, referring to the fact that they cannot seem to tell what is precipitating the outbreak. The marks can appear anywhere (or everywhere) on the body – legs, arms, trunk, hands, feet, armpits, even your face.

Causes of Chronic Urticaria

The exact cause of chronic urticaria is not known, but it is estimated that approximately 30-45% of chronic urticaria cases occur in people with an autoimmune disease or a disorder in which your immune system—which normally defends your body against bacteria, viruses, and other causes of illness—instead attacks your own bodily tissues.

Rheumatoid arthritis, type 1 diabetes, celiac disease, and autoimmune thyroid disorders are some of the autoimmune conditions associated with chronic urticaria.

Hashimoto’s thyroiditis is a common autoimmune thyroid disease and the leading cause of hypothyroidism (underactive thyroid). Another autoimmune thyroid condition is Graves’ disease, which is the most common cause of the opposite problem, hyperthyroidism or hyperthyroidism. Among people with chronic urticaria, Hashimoto’s disease is more common than Graves’ disease.

Autoimmune disease and chronic urticaria: what explains the link?

“The relationship between Hashimoto and chronic urticaria has been studied and observed almost since the 1980s,” says Betul Hatipoglu, MD, professor of medicine at Case Western Reserve University School of Medicine in Ohio. But it’s still unclear exactly how or why they are connected.

Sometimes chronic hives develop years after a person has been diagnosed with Hashimoto’s disease, notes Dr. Hatipoglu; other times a person first develops chronic urticaria and later (sometimes years later) is diagnosed with Hashimoto.

Scientists have found that chronic urticaria and Hashimoto’s disease have similarities, including high levels of immune chemicals (like interleukin-6) that activate the immune system and lower levels of cells that suppress immune responses (called regulatory T cells), compared to a person with a healthy immune system.

Additionally, blood tests show that people with chronic hives and those with Hashimoto’s disease have “autoantibodies” against the thyroid gland, also called antithyroid antibodies. A common antibody to Hives and Hashimoto is thyroid peroxidase antibody, or TPO.

Several theories have been proposed to explain the biological link between urticaria and thyroid autoimmunity. The first is that the immune system’s assault on the thyroid gland produces an increased immune response in the thyroid which leads to chronic inflammation in the rest of the body. This chronic inflammatory response causes immune cells in the skin, called mast cells, to overreact, releasing a chemical called histamine that causes the symptoms of hives.

Another theory is that Hashimoto’s hives stem from increased levels of a key hormone involved in normal thyroid activity, TSH (thyroid-stimulating hormone), which has some molecular similarities to pro-inflammatory cytokines. , a type of immune chemical.

TSH levels are elevated in Hashimoto’s disease due to the thyroid gland producing too little thyroid hormone. (When there is too little thyroid hormone in the blood, the pituitary gland in the brain secretes more TSH to try to stimulate the gland to produce more.) Sustained high levels of TSH can trigger the same inflammatory response chronic mentioned above, resulting in the release of histamine and hence hives.

Who is at risk for chronic urticaria?

Gender is a risk factor for chronic urticaria and thyroid disorders. “Chronic urticaria and Hashimoto’s disease are more common in women,” says Dr. Hatipoglu, “raising the possibility that sex hormones are involved.”

Scientists are also studying whether differences in the microbial composition of the large intestine, known as the gut microbiome, could be involved in autoimmune disorders, chronic urticaria or both. There is evidence that people with chronic hives have lower amounts of several types of bacteria normally found in our gut, including Lactobacillus and Bacteroides, compared to people who do not have chronic urticaria. But more studies are needed to definitively establish this connection.

How are chronic hives diagnosed?

Chronic urticaria is diagnosed on clinical observation of the characteristic red, itchy, or swollen skin along with a medical history of the recurring problem for at least six weeks. Your doctor will ask you how often hives occur, when they started, and how long they usually last. They’ll also likely ask you a bunch of additional questions that can help rule out the more direct causes of your hives, such as:

  • Have you recently been bitten or stung by an insect?

  • Have you had hives after a hot shower or after swimming in cold water? (Extremes of temperature can trigger histamine release.)

  • Did you sweat a lot or wear tight clothes before the hives flared up? (Also a potential trigger.)

  • Have you recently started taking a new medication or dietary supplement?

  • Do you notice that hives occur when you eat a particular food?

Your doctor can do blood or skin tests to determine if you have an allergy that is triggering hives, as well as tests to measure your thyroid hormone levels and check for thyroid antibodies.

You may also have a skin test where some of your own blood is injected into your skin to see if you have a skin reaction. A positive result in this test, called ASST (autologous serum skin test), indicates that your hives may be related to an autoimmune disease.

How are Hashimoto-related hives handled?

There are several medications that can help, but it may take some trial and error to find the perfect combination. In addition to seeing your endocrinologist, it’s a good idea to see an allergist or dermatologist to help control your hives, suggests Dr. Hatipoglu.

If you have Hashimoto’s disease, treating your underactive thyroid with levothyroxine (a synthetic form of thyroid hormone, sold under brand names such as Synthroid and Tirosint) may also relieve hives. Interestingly, there is also evidence that levothyroxine can relieve chronic hives in people who have not been diagnosed with Hashimoto’s disease.

Other medications your doctor may try include non-sedating oral antihistamines, such as fexofenadine (Allegra) or cetirizine (Zyrtec), available without a prescription; or omalizumab (Xolair), a monoclonal antibody that decreases the immune response responsible for hives. Omalizumab requires a prescription and is given by injection under the skin.

To reduce the unpleasant symptoms of hives like itching and swelling, you can try cold compresses or a topical anti-itch product like calamine lotion, hydrocortisone, or the antihistamine diphenhydramine (brand name Benadryl ). All are available in pharmacies. If certain situations seem to trigger your hives or make them worse (for example, very hot showers), try to avoid them.

Are hives in Hashimoto’s thyroiditis dangerous?

In and of themselves, no, although they can be disruptive and anxiety-provoking. An exception is if you scratch so much that it breaks the skin, which can lead to infection. All the more reason to work with your endocrinologist and allergist or dermatologist to get hives under control.

For more information and advice on living with chronic hives see this Complete Guide to Chronic Spontaneous Urticaria (CSU) from HealthCentralalso a member of the Remedy Health Media Network.

Remarks: This article was originally published November 30, 2021 and most recently updated December 1, 2021.