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What is Hashitoxicosis?

Learn if you are susceptible to developing hashitoxicosis because of your Hashmoto’s thyroiditis disease.
What is Hashitoxicosis?
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First, your doctor told you that you were hyperthyroid. But your nervousness, insomnia, and weight loss quickly turned into exhaustion, depression, and weight gain. What’s going on? The back and forth between hypothyroidism and hyperthyroidism could be Hashitoxicosis. In this article, we look at this sometimes confusing autoimmune condition. 

What is Hashitoxicosis?

Hashitoxicosis is an autoimmune condition first discovered by Hakaru Hashimoto in 1912. It is defined as a temporary hyperthyroid state in a patient with underlying Hashimoto’s disease. In Hashitoxicosis, the immune system overstimulates the thyroid gland and creates antibodies that attack the thyroid gland. These antibodies trigger the thyroid to overproduce thyroid hormone temporarily. Initially, this causes hyperthyroidism symptoms, but over time, it usually shifts back to either normal thyroid function or hypothyroidism

What are the causes of Hashitoxicosis?

Hashitoxicosis occurs as a result of an inflammatory autoimmune process where thyroid follicles and cells are destroyed, and excess thyroid hormones flood the bloodstream. The duration of Hashitoxicosis can vary but typically runs from two to six months. Eventually,  as the surge of thyroid hormones slows and the thyroid’s function is damaged by antibodies, Hashitoxicosis develops into – or returns to – Hashimoto’s thyroiditis and hypothyroidism. 

The cause of Hashitoxicosis is patient-specific and brings us back to the common triggers of autoimmune thyroid disease, including genetics, environmental exposures such as pollutants and tobacco smoke, nutritional deficiencies, infectious agents, dietary habits such as an intake of gluten, and others.

Stress can also be a trigger for the onset of autoimmune thyroid disease. In one case study, a 28-year-old patient with a history of Hashimoto’s and stable thyroid levels experienced a psychologically stressful event that triggered the onset of Hashitoxicosis. Hashitoxicosis can also occur during postpartum thyroiditis (after pregnancy), “silent thyroiditis,” thyroiditis de Quervain (usually caused by a viral infection and causes thyroid and neck pain). In some cases, Hashitoxicosis is the first stage of Hashimoto’s in a new patient. 

What are the symptoms of Hashitoxicosis?

The symptoms of Hashitoxicosis are consistent with the signs and symptoms of a mild to moderate case of hyperthyroidism. These symptoms of hyperthyroidism include:

  • goiter (an enlarged thyroid)
  • excessive sweating
  • hand tremor
  • an increased appetite
  • difficulty sleeping
  • unintentional weight loss
  • intolerance to heat
  • an irregular heartbeat
  • irritability and anxiety
  • panic attacks
  • changes in bowel habits and loose stools
  • migraines
  • muscle weakness
  • memory loss
  • infertility
  • hair loss

How is Hashitoxicosis diagnosed?

Diagnosing Hashitoxicosis starts with a comprehensive thyroid blood test panel. This panel should include TSH (thyroid stimulating hormone), free thyroxine (Free T4), and free triiodothyronine (Free T3), which can identify excess thyroid hormone production. Typically, TSH will be low, and Free T4 and Free T3 will be elevated in patients experiencing Hashitoxicosis. Testing for Thyroid Peroxidase Antibodies (TPOAb) is also essential if a diagnosis of Hashimoto’s needs to be confirmed.

Doctors often add an ultrasound to rule out whether the patient may have Graves’ disease. The ultrasound looks at the thyroid gland’s vascularization, defined as the process of growing blood vessels into a tissue to improve oxygen and nutrient supply. Graves’ disease is characterized by highly increased vascularization. In Hashimoto’s, normal or only slightly increased vascularization is evident. The ultrasound can also detect any toxic or hormone-producing thyroid nodules, which can sometimes cause temporary periods of hyperthyroidism in some patients. 

How is Hashitoxicosis treated?

The majority of Hashitoxicosis cases tend to resolve on their own. However, if symptoms persist or become more serious, doctors may treat patients with an antithyroid drug, such as methimazole, to lower thyroid hormone production. Careful monitoring is necessary, as eventually, the thyroid will shift into hypothyroidism. The antithyroid drug is typically discontinued at that point, and thyroid hormone replacement therapy is started to treat hypothyroidism. 

A note from Paloma

Monitoring thyroid levels is particularly important in patients with Hashitoxicosis. To make the process convenient and affordable, you can use the Paloma Complete Thyroid Test kit to test at home. This easy-to-use test kit evaluates TSH, Free T4, Free T3, and Thyroid Peroxidase Antibody (TPOAb) levels. 

Paloma’s team of thyroid-savvy doctors are ready to provide comprehensive thyroid care, including diagnosis, management, and optimal treatment of your underactive thyroid. Paloma’s doctors will work with you to develop an effective and responsive treatment program, including thyroid medications, to help safely and effectively normalize your thyroid function and resolve your symptoms.

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Hashitoxicosis: Symptoms, Causes, Diagnosis, and Treatment. Verywell Health.

Hashitoxicosis – Three Cases and a Review of the Literature. European Endocrinology. Published online November 17, 2011.

Postpartum Thyroiditis. Published August 8, 2021.

Tabassom A, Edens MA. De Quervain Thyroiditis. PubMed. Published 2020.

Morris B. Hashitoxicosis: An Uncommon Presentation of Autoimmune Thyroid Disease. 2013;17. Accessed February 13, 2023.

Vascularization - an overview | ScienceDirect Topics.

Shahbaz A, Aziz K, Umair M, Sachmechi I. Prolonged Duration of Hashitoxicosis in a Patient with Hashimoto’s Thyroiditis: A Case Report and Review of Literature. Cureus. Published online June 14, 2018. doi:

Vita R, Cernaro V, Benvenga S, Vita R, Cernaro V, Benvenga S. Stress-induced hashitoxicosis: case report and relative HLA serotype and genotype. Revista da Associação Médica Brasileira. 2019;65(6):830-833. doi:

Hashimoto thyroiditis: an evidence-based guide to etiology, diagnosis and treatment. Accessed February 13, 2023.

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Neeyaz Zolfaghari

Holistic Nutritionist and Nourishment Coach

Neeyaz Zolfaghari is the founder of Unspoken Nutrition, a nutrition and lifestyle brand dedicated to helping others find and create harmony with their daily habits to support their wellbeing and ‘health’. Her journey began over a decade ago, when she was diagnosed with two autoimmune diseases. Knowing what she learned from her upbringing, Neeyaz turned to nutrition as the first pillar of her healing. As her body began to heal on a physical level, she began to learn how our minds, bodies and souls are all innately connected.  

Now as an Integrative Nutritionist and Patient Advocate, Neeyaz offers the people she works with the support, guidance, and tools they need in order to live a fulfilled life. While Neeyaz initially endeavored to make a difference at the individual level, her vision grew to embrace broader community impacts. She is currently pursuing her Masters in Public Health, serving as a testament to her unwavering commitment to instigate change on a grander scale.

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