Symptoms of hypothyroidism may resemble seasonal allergies, so some people may mistake the two. Additionally, some studies suggest a link between hypothyroidism and allergies.

However, evidence suggesting that hypothyroidism, also called underactive thyroid, causes seasonal allergies is limited.

Possible symptoms of both hypothyroidism and seasonal allergies include congestion and runny nose. If a person has other symptoms of hypothyroidism, like cold intolerance, hair loss, and fatigue, they should contact a doctor.

Keep reading to learn about hypothyroidism and seasonal allergies.

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Changes in nasal symptoms, such as runny nose, may occur in people with hypothyroidism. However, hypothyroidism is not known to cause allergies.

Like seasonal allergies, certain forms of hypothyroidism result from an overactive immune system. For example, in Hashimoto’s thyroiditis and Graves’ disease, the immune system produces antibodies that attack the thyroid.

A 2022 study with 434 participants investigated the relationship between hypothyroidism and allergies.

Researchers explored whether the participants with anti-thyroid antibodies had a higher rate of allergies. Researchers concluded there was a significant association between anti-thyroid antibodies and allergic diseases.

To explain this association, researchers suggest the immune system produces complexes of proteins and antibodies that attach to certain immune cells. This phenomenon can activate the immune system and cause certain allergic reactions.

However, this study did not focus on seasonal allergies and only included a small number of Chinese participants. To understand whether hypothyroidism causes seasonal allergies, more research is necessary.

Symptoms of hypothyroidism and seasonal allergies may sometimes be similar.

Common symptoms of seasonal allergies include:

  • runny nose
  • nasal congestion
  • sneezing
  • throat clearing
  • dark circles under the eyes
  • watery eyes
  • itchy palate

Runny nose is a symptom of both seasonal allergies and hypothyroidism.

In a 2021 study, researchers recruited people recently diagnosed with hypothyroidism. Participants had runny noses that improved with levothyroxine (Synthroid) treatment, a drug used to treat hypothyroidism.

However, not all people with low thyroid hormone have a runny nose. Common symptoms of hypothyroidism include:

  • intolerance to cold temperatures
  • puffiness
  • reduced sweating
  • changes in the skin, such as dryness
  • changes in voice
  • changes in the menstrual cycle
  • hair loss
  • constipation
  • fatigue
  • muscle cramps
  • sleep problems
  • weight gain

To diagnose hypothyroidism, doctors measure thyroid stimulating hormone levels in the blood. They may also measure serum levels of the thyroid hormones called T3 and T4. If these test results are abnormal, they may order a panel of thyroid antibody tests.

Doctors will also verify other factors in the blood to check for other possible reasons for a person’s symptoms. These include diseases of the immune system.

Since symptoms of hypothyroidism are not always present or specific, doctors may need to consider other conditions causing the person’s symptoms. Other possible diagnoses may include:

  • anemia
  • iodine deficiency
  • Addison disease
  • chronic fatigue syndrome
  • depression

Diagnosing seasonal allergies does not require a blood test. Instead, doctors use a thorough medical history focusing on the person’s description of their symptoms.

Questions doctors ask include when symptoms started, how long they lasted, and how often they occur.

A discussion about suspected allergens that caused the symptoms is also necessary.

The following are treatment options for hypothyroidism and seasonal allergies.


Treatment for hypothyroidism may include taking a thyroid supplement. Levothyroxine (Synthroid) is an oral tablet doctors prescribe for adults and children with hypothyroidism.

Doctors prescribe the most appropriate dose by checking a person’s thyroid stimulating hormone levels in their blood.

If a person still has symptoms after treatment with levothyroxine, another condition may be causing their symptoms.

Managing hypothyroidism depends on the symptoms a person experiences. While some symptoms may resolve with the appropriate levothyroxine dosage, people may still need to manage weight and skin changes.

Learn more about treatment for hypothyroidism.

Seasonal allergies

Treating allergy symptoms may be easier than treating hypothyroidism symptoms since people can purchase over-the-counter (OTC) allergy medications.

OTC antihistamines, such as diphenhydramine (Benadryl) and cetirizine (Zyrtec), help improve allergy symptoms quickly.

Doctors may prescribe intranasal steroids, such as triamcinolone acetonide (Nasacort), and leukotriene receptor antagonists, like montelukast (Singulair).

If these treatments do not work, people may require immunotherapy.

Learn more about treatment for seasonal allergies.

People experiencing a runny nose or sneezing can speak with a doctor or pharmacist. A pharmacist can help people living with seasonal allergies find ways to improve their symptoms, and they can recommend OTC medications.

A runny nose is a symptom of many health conditions. It can be hard to know its exact cause.

People with a runny nose and symptoms suggesting hypothyroidism can talk with a doctor. The doctor can recommend specific tests to check for hypothyroidism.

Some symptoms of hypothyroidism, like runny nose, are the same as seasonal allergies. However, having a runny nose does not mean a person has hypothyroidism.

Hypothyroidism is unlikely to cause seasonal allergies.

However, some researchers suggest a link between certain autoimmune diseases that attack the thyroid and some allergic disorders. More clinical research is necessary to confirm this hypothesis.