Hormonal imbalance is one of the many causes of hair loss. Changes in hormonal level like in pregnancy, after child birth, thyroid hormone imbalance are some of the situations which also cause hair loss.
To understand the role of thyroid hormone in hair loss, let us first see what is thyroid gland and how does it works in our body?
Thyroid gland is situated in neck wrapped around the trachea (windpipe) below the voice box, it has two lobes and an isthmus in the centre. The main function of this gland is to secrete thyroid hormones which are Thyroxine (T4) and Triiodothyronine (T3). The secretion of these hormones is controlled via a well regulated mechanism.
The brain sends signal to the pituitary gland, which is the master gland. This in turn will produce TSH and this TSH will then regulate the production of thyroid hormones from gland. Based on the amount of thyroid hormones in blood, the thyroid gland will send the report to pituitary to either increase or decrease the production of hormones.
Let's have a quick look upon the functions of thyroid hormones.
It regulates the metabolism of protein, carbohydrate and fat. These hormones are responsible for proper growth of children and development of brain in foetus. These are responsible for proper functioning of cardiovascular system, nervous system, reproductive system.
Lets see what hair problem does a patient have in abnormal thyroid functions
In both hypo and hyperthyroidism, person observe diffuse thinning of hair on scalp and in hypothyroidism this can also be seen in outer part of eyebrow. One may notice that due to decrease in density scalp is becoming visible and also clumps of hair going down the drain while taking shower. There may be changes in hair texture .The hair becomes dry and brittle. In hypothyroid this is due to the failure to resume anagen hair because of reduction in the metabolic rate causing the loss of hair without getting it replaced.
Many patients with hyperthyroidism and hypothyroidism have auto-immune thyroiditis. Alopecia areata which is common cause of hair loss is an autoimmune disorder and has frequent association with other autoimmune diseases including autoimmune thyroiditis. Studies have shown that hypothyroidism is the commonest thyroid abnormality associated with alopecia areata. These autoimmune responses are mainly due to T cell mediated immunity. There are some clues that there is T cell mediated autoimmune response against some antigen in hair follicle. Studies have shown T cell lymphocytic infiltration in epithelial cells of hair follicles, keratinocytes and cells of thyroid, which not only points to the involvement of these T cells in alopecia and thyroiditis but also to their association with one another.
How to suspect that one has some thyroid abnormality?
In hypothyroid state there are low levels of thyroid hormones and one of the important cause for this is iodine deficiency. One may have intolerence to cold, goitre, fatigue, constipation, weight gain, depression, dry and itchy skin in this under production state.
In hyperthyroidism due to over production of thyroid hormones one may have intolerence to heat, weight loss, increase in sweating with typically warm and moist hands, palpitation, protruding eyes.