Could a Hives Rash Be a Sign of Thyroid Disease?

Thyroid disease can sometimes cause repeated bouts of an itchy skin rash known as hives. In fact, up to 30% of people with chronic hives (also known as chronic urticaria) have an underlying autoimmune disease that affects the thyroid gland in the neck.

Chronic hives are especially common in people with Hashimoto's thyroiditis, an autoimmune disease that causes hypothyroidism (an underactive thyroid gland).

This article looks at the connection between chronic hives and thyroid disease. It also discusses the various tests and treatments used to diagnose and manage this recurrent skin condition.

Symptoms of Rash Due to Thyroid Disease

Hives associated with thyroid disease are similar to hives from other causes. The rash tends to develop rapidly and resolve in a relatively short period of time.

With that said, some forms of urticaria are chronic, meaning that they last for more than six weeks and recur frequently over the course of months or years.

Symptoms of chronic urticaria include:

• Patches of raised red or skin-colored welts (known as wheals)
• Wheals that can change shape and size, sometimes fading and later reappearing
• Itching, sometimes severe, and/or a stinging or burning sensation

This itchy rash can occur on the neck, chest, back, face, and buttocks.

Hives associated with autoimmune thyroid disease are most often chronic.

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Why Does Thyroid Disease Cause a Rash?

Autoimmune diseases are those in which the body's immune system mistakenly attacks its own cells and tissues. It does so with immune proteins called autoantibodies that cause chronic or recurrent attacks known as flares.

In the case of autoimmune thyroid disease, the thyroid gland is the target of the assault.

Autoantibodies that target a specific receptor found in tissues under the skin are produced during a flare. These "turn on" these receptors, triggering the production of a protein known as immunoglobulin E (IgE) and the chain of events that lead to allergies.

Autoimmunity is thought to be one of the most common causes of chronic hives. Not all autoimmune diseases trigger an IgE response, however.

Hashimoto's Thyroiditis

Hashimoto's thyroiditis is the most common kind of autoimmune thyroid disease.

Chronic hives may occur in tandem with an autoimmune flare or when the disease is subclinical (meaning active but without overt symptoms). During subclinical episodes, even low levels of autoantibodies can trigger an IgE response.

While Hashimoto's thyroiditis may increase the risk of chronic hives, not everyone who has Hashimoto's will get hives. This suggests that other environmental or genetic factors may contribute to the risk.

Related Conditions

There are other skin symptoms that can present with thyroid disease.

Pretibial myxedema is a skin condition that can occur with autoimmune thyroid diseases like Hashimoto's thyroiditis and Graves' disease. It causes deposits of a natural lubricating fluid called hyaluronic acid under the skin, causing pink or purplish nodules on the lower legs or feet.

Other skin symptoms that can appear with hypothyroidism include:

• Mottling or discoloration
• Cold hands and feet
• Dry, coarse texture
• Cracking of the skin
  

Additionally, hyperthyroidism can lead to symptoms such as:

• Flushing of the face
• Redness on the palms of your hands
• Excessive sweating on the palms of your hands and/or the soles of your feet
• Thin, soft, and sometimes shiny skin
  

How to Treat a Thyroid Rash

Hives are often one-off events that will clear on their own without treatment, never to be seen again. Rashes that recur should generally be treated, particularly if they are severe or persistent.

Regardless of the cause of hives, the goals of treatment are the same: to relieve symptoms and prevent a recurrence. 

The first and arguably most important goal is to avoid any triggers that instigate hives. These vary from one person to the next. They may include:

• Food allergies
• Strenuous exercise
• Sudden changes in temperature
• Stress

Other treatment options include topical anti-itch creams, oral antihistamines, and thyroid hormone replacement.

Topical Anti-Itch Creams

Topical creams and sprays used to reduce itch and inflammation may be useful in managing the symptoms of hives, particularly if the hives are not widespread.

Over-the-counter options include:

• Topical 1% hydrocortisone cream
• Antihistamine creams, like Benadryl Itch Stopping Cream
• Lidocaine cream or spray
  

Antihistamines and Other Allergy Drugs

If hives are widespread, oral antihistamines may be a better option. These drugs block a chemical called histamine that is involved in allergic reactions.

Antihistamines are the first line of treatment for moderate to severe hives. Second-generation antihistamines are usually recommended, as they do not cause drowsiness.

Over-the-counter antihistamines used to treat hives include:

• Allegra (fexofenadine)
• Claritin (loratadine)
• Zyrtec (cetirizine)

If the itchiness or burning are interfering with your sleep, first-generation antihistamines like Benadryl (diphenhydramine) are mildly sedating and may help.

Other drugs may be prescribed if oral antihistamines fail to provide relief, including:

• Histamine H2 antagonists like Tagamet (cimetidine) and Pepcid (famotidine), available over the counter or by prescription
• Leukotriene receptor antagonists like Singulair (montelukast), available by prescription
• Corticosteroids like prednisone, available by prescription

Levothyroxine

Levothyroxine, sold under the name Synthroid, Levoxyl, and others, is a synthetic thyroid hormone used to treat hypothyroidism. It does not treat the underlying autoimmunity that causes Hashimoto's thyroiditis, but it can normalize hormone levels so that you are less likely to experience hypothyroid symptoms.

Levothyroxine has been shown to work better than antihistamines in relieving hives related to autoimmune thyroid disease. It also tends to work for a longer period of time.

Are There Tests to Diagnose the Cause of Chronic Hives?

Hives can usually be diagnosed by their appearance. Identifying the underlying cause is a different issue and often involves a process of elimination to narrow the possible causes.

This may involve blood tests and skin biopsies to rule out infectious or inflammatory conditions (like vasculitis). Skin-prick tests and food challenges may be used to rule out specific types of allergies or food intolerances.

If autoimmune thyroid disease is suspected, your healthcare provider may order tests to help confirm the diagnosis, including:

• Autologous skin serum test (ASST), a procedure used to measure your autoimmune reactivity to histamine injected beneath the skin
• Thyroid hormone tests, a blood test used to measure the level of the thyroid hormones TSH, T3, and T4
• Autoimmune thyroid tests, a blood test used to detect thyroid autoantibodies such as anti-TSH, anti-TPO, and anti-Tg

Differential Diagnoses

Chronic hives can occur as a result of autoimmunity. But, it can also occur independently of thyroid disease for any number of reasons, including:

• Food allergies and intolerance
• Exposure to cold (cold urticaria)
• Stress (stress-induced urticaria)
• Sunlight (solar urticaria)
• Exercise (exercise-induced urticaria)
• Pressure on the skin, such as from a tight waistband (pressure urticaria)
• Scratching (dermatographism)

In some cases, there may be no apparent reason for a recurrent outbreak. This is referred to as chronic idiopathic urticaria (CIU).

There may be times when hives are an indication of a severe, whole-body allergy known as anaphylaxis. Anaphylaxis is a medical emergency that can lead to shock, coma, heart, or respiratory failure, and death if left untreated.

When to See a Healthcare Provider

Hives are often short-lasting and non-severe. If you think your rash is associated with a thyroid condition, let your healthcare provider know right away. They may refer you to an endocrinologist, a physician who specializes in the diagnosis and treatment of hormonal disorders like thyroid disease.

If diagnosed, thyroid disease requires lifelong management with appropriate therapy.

Generally speaking, any time an outbreak of hives is sudden, rapid, and severe, you should seek immediate medical attention.

Call 911 or go to your nearest emergency room if you experience the signs of anaphylaxis, including:

• A sudden outbreak of hives or rash
• Difficulty breathing, including shortness of breath and wheezing
• Abnormally rapid heartbeat
• Lightheadedness or fainting
• Swelling of the lips, face, or throat
• Sudden clammy skin
• A feeling of impending doom
  

Summary

Hives (urticaria) are skin reactions that cause raised, itchy welts. Those that are chronic— lasting for more than six weeks or recurring over months or years—may be the result of an autoimmune disease like Hashimoto's thyroiditis.

Hives can be treated with topical anti-itch creams or oral antihistamines. If autoimmune thyroid disease is involved, a synthetic thyroid hormone called levothyroxine may help prevent or treat a hives outbreak.