Thyroid Disorder and Hair Loss
The thyroid is a butterfly-shaped gland that is located at the front of your neck. It's an important part of your endocrine system; and while it's small in size it's vital to the functioning of the body and has an effect on every cell. When the hormone TSH is produced by your pituitary gland, it signals to the thyroid to create two hormones – thyroxine and triiodothyronine.
These thyroid hormones control your metabolism and how energy is used by different parts of the body. The pituitary gland constantly monitors the levels of these thyroid hormones in your blood stream and tell the thyroid when it needs to increase or decrease its supply of hormones.
Types of thyroid disorders
There are two key ways your thyroid can malfunction but there are a number of underlying conditions and causes that leads to both.
1. Hypothyroidism (An underactive thyroid)
Hypothyroidism refers to a condition where the thyroid does not produce enough hormones and your metabolism slows down as a result. The NHS estimates that 15 in 1,000 women and 1 in 1,000 men in the UK are affected by the condition. There are also between 1 in 3,500 and 1 in 4,000 babies born each year in the UK with congenital hypothyroidism.
Hypothyroidism can occur as a result of some of the following:
- Hashimoto's thyroiditis is an autoimmune disorder which causes the body to attack the tissue of the thyroid and can eventually cause it to stop producing hormones.
- Thyroid gland surgery or exposure to high levels of iodine.
- Treatments with Lithium or treatments with hyperthyroid drugs that can lower the hormone production too much.
- Failure of the pituitary gland or a genetic predisposition to the condition.
2. Hyperthyroidism (An overactive thyroid)
Hyperthyroidism refers to a condition where the thyroid produces and releases too much hormones, which then speeds up your metabolism too much. A woman is 10 times more likely to develop this condition and the NHS estimate that as many as 1 in 50 women in the UK have the condition.
Hyperthyroidism can occur as a result of some of the following:
- Graves' disease is the most common and is responsible for 80% of hypothyroid conditions. It's an autoimmune disease where high levels of hormones are secreted as a result of stimulation from antibodies.
- Plummer's disease, which is also known as toxic multinodular goitre, occurs when the whole thyroid gland becomes enlarged and lumps develop. These lumps start over-producing hormones.
- Treatments with hypothyroid drugs that stimulate overproduction.
- Thyroiditis, which causes an infection in the thyroid or causes it to become inflamed. This can lead to a temporary surge in hormones produced.
Symptoms of thyroid disease
Because the thyroid impacts on every cell in the body, the symptoms can be wide ranging. Some of the most common symptoms of hypothyroidism include:
- Tiredness and fatigue
- Unexplained weight gain
- Depression and low mood
- Being sensitive to the cold
- Dry skin and hair
- Experiencing muscle aches
These symptoms can gradually develop over time, so they can go unnoticed for many years. To diagnose an under-active thyroid, you will need to get a blood test called a thyroid function test.
Hyperthyroidism can cause a range of symptoms that are associated with the speed up of your metabolism. These can include:
- Nervousness and anxiety
- Hyperactivity where you're unable to stay still and you're full of nervous energy
- Unexplained weight loss
- The formation of a goitre; a noticeable lump as a result of the thyroid gland swelling
How do thyroid problems cause hair loss?
Hair loss can be caused by severe and prolonged hypothyroidism and hyperthyroidism when the hormone imbalances caused as a result, affect the growth of hair. Human hair goes through a growth phase, a rest phase (telogen phase) where hair is shed, and a new hair growth phase. It's thought that thyroid problems can disrupt the new hair growth phase. Because this is part of a longer cycle, it can take several months before the hair loss is noticed. This type of hair loss tends not be limited to specific areas and the loss of hair tends to be diffuse, affecting the whole scalp.
Some anti-thyroid treatment drugs are also thought to contribute to hair loss, as a rare side effect. Although it can be difficult to ascertain whether this is specifically related to the treatment or whether it is as a result of the underlying hyperthyroid condition. These medications include carbimazole and propylthiouracil.
Autoimmune disorders and diseases such as Hashimoto's thyroiditis and Grave's disease are the most common cause of thyroid disorders. These autoimmune disorders can also place you at an increase likelihood of developing other autoimmune conditions that can cause hair loss, such as alopecia areata. This can cause circular, patchy, discrete areas of hair loss.
Treating thyroid disorders and hair loss
Taking daily hormone tablets called levothyroxine, which helps increase your levels of thyroxine produced, can treat an underactive thyroid. For those with hypothyroidism, treatment will normally be required for the rest of your life.
An overactive thyroid can be treated by taking medications that will lower the production of thyroid hormones – such as carbimazole and methimazole. Some people can also benefit from radioiodine treatment, which shrinks the thyroid gland and as a result reduces the level of hormones it produces. In a small number of cases, surgery may be carried out to remove some or all of the thyroid gland.
If you have hair loss as a result of a thyroid disorders, once this under control and hormone levels are balanced, hair growth should resume and within a few months the hair loss should start reversing itself. This hair growth can be unpredictable and some find that their hair regrows with a different colour or texture.